Synthesis and study of structural and magnetic properties of superparamagnetic Fe3O4@SiO2 core/shell nanocomposite for biomedical applications. Article 2, Volume 1, Issue 2, Winter 2014, Page 71-78
Objective(s):
This paper describes coating of magnetite nanoparticles (MNPs) with amorphous silica shells.
Materials and Methods:
First, magnetite (Fe3O4) NPs were synthesized by co-precipitation method and then treated with stabilizer molecule of trisodium citrate to enhance their dispersibility. Afterwards, coating with silica was carried out via a sol-gel approach in which the electrostatically stabilized MNPs were used as seeds. The samples were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM).
Results:
The results of XRD analysis implied that the prepared nanocomposite consists of two compounds of crystalline magnetite and amorphous silica that formation of their core/shell structure with the shell thickness of about 5 nm was confirmed by TEM images. The magnetic studies also indicated that produced Fe3O4@SiO2 core/shell nanocomposite exhibits superparamagnetic properties at room temperature.
Conclusion:
These core/shell structure due to having superparamagnetic property of Fe3O4 and unique properties of SiO2, offers a high potential for many biomedical applications.
Keywords
Magnetite; Silica; Core-shell structure; Superparamagnetism; Biomedical applications
chitosan nanoparticles synthesis and application in various fields i.e. biocompatible fruit preservatives, water treatment with non toxic substrate, cotton functionalization, etc.
Synthesis and Structural Characterization of Cu Substituted Ni-Zn Nano-Ferrit...IJERA Editor
The ferrite nano particles having chemical formula Ni0.2CuxZn0.8-xFe2O4 (where x=0.0 to 0.8 with step of 0.2) were synthesized by Citrate-Gel Auto Combustion method at low temperature. The synthesized powders were sintered at 500oC for 4 hours in air and characterised by XRD, SEM with EDS. XRD analysis of prepared samples were confirmed the single phase cubic spinel Structure. The crystallite size (D) of prepared ferrites were in the range of 24-73nm. The values of lattice parameter (a) decreased and X-ray density (dx) were increased with the increasing of Cu substitution. The surface morphology of the prepared samples was investigated by Scanning Electron Microscope(SEM). An elemental composition of the samples was studied by Energy Dispersive Spectroscopy(EDS). The observed results can be explained on the basis of composition and crystal size.
Background- Chitosan is a natural, biocompatible, biodegradable, nontoxic and easily available polymer that can be used to prepare nanoparticles. Chitosan nanoparticles can be widely used in pharmaceutical industries as an antimicrobial agent or as drug delivery vehicle. Objectives- Aim of the study was to prepare chitosan nanoparticles and characterize them. Methods: Chitosan nanoparticles were prepared by ionic gelation method and characterized by UV-Vis spectroscopy, FTIR (Fourier transform infrared spectroscopy), DLS (Dynamic Light Scattering) and Scanning electron microscopy (SEM). Results- The present study showed that chitosan nanoparticles were successfully prepared by ionic gelation method. The obtained chitosan nanoparticles were characterized and study revealed that they are stable spherical in shape. The size of chitosan nanoparticles (CSNPs) at selected concentration was 216 nm and zeta potential 50mV was done by zeta sizer Nano S (Malvern, UK). Conclusion- Chitosan nanoparticles were successfully prepared by ionic gelation method.
Key-words- Chitosan, Chitosan nanoparticles, DLS, FTIR, SEM, UV-Vis spectroscopy
chitosan nanoparticles synthesis and application in various fields i.e. biocompatible fruit preservatives, water treatment with non toxic substrate, cotton functionalization, etc.
Synthesis and Structural Characterization of Cu Substituted Ni-Zn Nano-Ferrit...IJERA Editor
The ferrite nano particles having chemical formula Ni0.2CuxZn0.8-xFe2O4 (where x=0.0 to 0.8 with step of 0.2) were synthesized by Citrate-Gel Auto Combustion method at low temperature. The synthesized powders were sintered at 500oC for 4 hours in air and characterised by XRD, SEM with EDS. XRD analysis of prepared samples were confirmed the single phase cubic spinel Structure. The crystallite size (D) of prepared ferrites were in the range of 24-73nm. The values of lattice parameter (a) decreased and X-ray density (dx) were increased with the increasing of Cu substitution. The surface morphology of the prepared samples was investigated by Scanning Electron Microscope(SEM). An elemental composition of the samples was studied by Energy Dispersive Spectroscopy(EDS). The observed results can be explained on the basis of composition and crystal size.
Background- Chitosan is a natural, biocompatible, biodegradable, nontoxic and easily available polymer that can be used to prepare nanoparticles. Chitosan nanoparticles can be widely used in pharmaceutical industries as an antimicrobial agent or as drug delivery vehicle. Objectives- Aim of the study was to prepare chitosan nanoparticles and characterize them. Methods: Chitosan nanoparticles were prepared by ionic gelation method and characterized by UV-Vis spectroscopy, FTIR (Fourier transform infrared spectroscopy), DLS (Dynamic Light Scattering) and Scanning electron microscopy (SEM). Results- The present study showed that chitosan nanoparticles were successfully prepared by ionic gelation method. The obtained chitosan nanoparticles were characterized and study revealed that they are stable spherical in shape. The size of chitosan nanoparticles (CSNPs) at selected concentration was 216 nm and zeta potential 50mV was done by zeta sizer Nano S (Malvern, UK). Conclusion- Chitosan nanoparticles were successfully prepared by ionic gelation method.
Key-words- Chitosan, Chitosan nanoparticles, DLS, FTIR, SEM, UV-Vis spectroscopy
Synthesis and Evaluation of the Cytotoxic and Anti-Proliferative Properties o...IJEAB
Doxorubicin (Dox) is a potent chemotherapeutic agent used in the treatment of cancer. In the present study, pH responsive chitosan polymer coated Dox nanoparticle (Composite) was developed to investigate targeted drug delivery against breast cancer. The anticancer drug DOX-ZnO QDs was loaded to the chitosan nanoparticles. The synthesized free and drug loaded nanoparticle were analyzed using Fourier transmission electron microscopy (FTIR) and UV-Visible spectroscopy(UV-Vis). The particle size was measured using Transmission Electron Microscopy (TEM). Further, the composite was evaluated for its anticancer effects. Drug release analysis showed significantly larger amount of drug released in acidic pH of 5.0 compared to pH 7.4. The composite was significantly more cytotoxic to the breast cancer cells MCF-7 and SKBR-3. The composite was however, less toxic to HEK-293 human embryonic kidney cells confirming minimum side effects on normal cells andcytotoxic to tumor cells. DAPI staining showed nuclear degradation in composite treated breast cancer cells. The cellular uptake of the composite was analyzed by confocal microscopy. The composite induced a G0/G1 phase arrest in breast cancer cells and the number of colonies formed by the composite treated breast cancer cells formed less number of colonies compared to free NP. Our results showed that our composite could serve as a promising therapeutic approach to improve clinical outcomes against various malignancies.
Synthesis of graphene oxide-TiO2 nanocomposite as an adsorbent for the enrich...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
In our study, graphene oxide-TiO2 nanocomposite (GO/TiO2) was prepared and used for the enrichment of rutin from real samples for the first time.
Materials and Methods:
The synthesized GO/TiO2 was characterized by X-ray diffraction, scanning electron microscopy, and FT-IR spectra. The enrichment process is fast and highly efficient. The factors including contact time, pH, and amount of GO/TiO2 affecting the adsorption process were studied.
Results:
The maximum adsorption capacity for ciprofloxacin was calculated to be 59.5 mg/g according to the Langmuir adsorption isotherm. The method yielded a linear calibration curve in the concentration ranges from 15 to 200 μg/L for the rutin with regression coefficients (r2) of 0.9990. The limits of detection (LODs, S/N=3) and limits of quantification (LOQs, S/N=10) were found to be 8 μg/Land 28 μg/L, respectively. Both the intra-day and inter-day precisions (RSDs) were < 10% .
Conclusion:
The developed approach offered wide linear range, and good reproducibility. Owing to the diverse structures and unique characteristic, GO/TiO2 possesses great potential in the enrichment and analysis of trace rutin in real aqueous samples.
PPT on "Functionalization of Nanoparticles and Nanoplatelets" by Deepak rawalDeepak Rawal
Presentation on Functionalization of nanoparticles, magnetic nanoparticles, chemical funtionalization, funtionalization of carbon nanotubes and their applications. Introduction about graphite nanoplatelets.
characteristics exploration of n ii cuzn nano-composite coated permanent magnetsIJEAB
This paper presents the synthesis of compound using Citrate Precursor Sol- Gel Method and Ball millingfor grinding the compound. X-ray diffraction measurements (XRD) confirmed the formation of single-phase cubic spinel structure. The average crystallite size was calculated using XRD pattern and confirmed by Scanning Electron Microscope (SEM). The electromagnetic properties were investigated using Vector Network Analyzer (VNA) and molar magnetic susceptibility measurements. The magnetic measurements have proved that the entire preparation method has considerable effect in enhancing the magnetic properties of the system. And an application of PMBLDC machine design with ferrite coated permanent magnets having competitive power density and efficiency. The influence of temperature variation on the magnets on the electric machine performance is also observed.
Synthesis, Characterization, Antibacterial and DNA Binding Studies of Mn (II)...IOSRJAC
Mn (II) complex of the Schiff base (L), 3-(2-(2-hydroxy-3-methoxybenzylidene) hydrazinyl) quinoxalin-2(1H)-one (VHQO) was prepared and characterized by IR, UV-VIS, Mass, Elemental analysis, TGDTA, magnetic susceptibility and conductivity measurements. VHQO behaved as monobasic, tridentate ligand and formed 1:2 complex (ML2) with the metal ion (M) coordinating through ring nitrogen, azomethine nitrogen and phenolic oxygen. Thermal analysis of the complex indicated the absence of lattice and coordinated water. Based on the spectral and analytical data, octahedral geometry was assigned to the complex. Antibacterial activity of the complex against gram positive bacteria, Bacillus subtillis, Staphylococcus aureus, and gram negative bacteria, Escherichia coli, Proteus vulgaris, Pseudomonas aeroginosa , and Klebsiella pneumonia was studied. The interaction of the complex with Calf Thymus DNA (CT-DNA) was studied by absorption spectroscopy and the intrinsic binding constant was calculated.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Study of magnetic and structural and optical properties of Zn doped Fe3O4 nan...Nanomedicine Journal (NMJ)
Objective(s):
This paper describes synthesizing of magnetic nanocomposite with co-precipitation
method.
Materials and Methods:
Magnetic ZnxFe3-xO4 nanoparticles with 0-14% zinc doping (x=0, 0.025, 0.05, 0.075, 0.1 and 0.125) were successfully synthesized by co-precipitation method. The prepared zinc-doped Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and UV-Vis spectroscopy.
Results:
results obtained from X-ray diffraction pattern have revealed the formation of single phase nanoparticles with cubic inverse spinal structures which size varies from 11.13 to 12.81 nm. The prepared nanoparticles have also possessed superparamagnetic properties at room temperature and high level of saturation magnetization with the maximum level of 74.60 emu/g for x=0.075. Ms changing in pure magnetite nanoparticles after impurities addition were explained based on two factors of “particles size” and “exchange interactions”. Optical studies results revealed that band gaps in all Zn-doped NPs are higher than pure Fe3O4. As doping percent increases, band gap value decreases from 1.26 eV to 0.43 eV.
Conclusion:
These magnetic nanocomposite structures since having superparamagnetic property
offer a high potential for biosensing and biomedical application.
Spinel Ferrite Nanoparticles Synthesis, Characterization and Applicationsijtsrd
Spinel ferrite nanoparticle have attracted a great attention due to its widely used in several areas such as in electronics devices, biomedical, catalyst and wastewater treatment. The synthesis, characterisation and application of spinel ferrite nanoparticles in various fields is focuses in this review paper. The most commonly used synthesis methods along with their advantages and limitations were discussed. The most common characterisation techniques and their applications such as power applications, biomedical applications, inductors, high frequency and Electromagnetic Interference EMI Suppression are briefly reviewed. D. L. Chaudhari | D. S. Choudhary | K. G. Rewatkar "Spinel Ferrite Nanoparticles: Synthesis, Characterization and Applications" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-3 , April 2020, URL: https://www.ijtsrd.com/papers/ijtsrd30684.pdf Paper Url :https://www.ijtsrd.com/physics/nanotechnology/30684/spinel-ferrite-nanoparticles-synthesis-characterization-and-applications/d-l-chaudhari
Synthesis and Evaluation of the Cytotoxic and Anti-Proliferative Properties o...IJEAB
Doxorubicin (Dox) is a potent chemotherapeutic agent used in the treatment of cancer. In the present study, pH responsive chitosan polymer coated Dox nanoparticle (Composite) was developed to investigate targeted drug delivery against breast cancer. The anticancer drug DOX-ZnO QDs was loaded to the chitosan nanoparticles. The synthesized free and drug loaded nanoparticle were analyzed using Fourier transmission electron microscopy (FTIR) and UV-Visible spectroscopy(UV-Vis). The particle size was measured using Transmission Electron Microscopy (TEM). Further, the composite was evaluated for its anticancer effects. Drug release analysis showed significantly larger amount of drug released in acidic pH of 5.0 compared to pH 7.4. The composite was significantly more cytotoxic to the breast cancer cells MCF-7 and SKBR-3. The composite was however, less toxic to HEK-293 human embryonic kidney cells confirming minimum side effects on normal cells andcytotoxic to tumor cells. DAPI staining showed nuclear degradation in composite treated breast cancer cells. The cellular uptake of the composite was analyzed by confocal microscopy. The composite induced a G0/G1 phase arrest in breast cancer cells and the number of colonies formed by the composite treated breast cancer cells formed less number of colonies compared to free NP. Our results showed that our composite could serve as a promising therapeutic approach to improve clinical outcomes against various malignancies.
Synthesis of graphene oxide-TiO2 nanocomposite as an adsorbent for the enrich...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
In our study, graphene oxide-TiO2 nanocomposite (GO/TiO2) was prepared and used for the enrichment of rutin from real samples for the first time.
Materials and Methods:
The synthesized GO/TiO2 was characterized by X-ray diffraction, scanning electron microscopy, and FT-IR spectra. The enrichment process is fast and highly efficient. The factors including contact time, pH, and amount of GO/TiO2 affecting the adsorption process were studied.
Results:
The maximum adsorption capacity for ciprofloxacin was calculated to be 59.5 mg/g according to the Langmuir adsorption isotherm. The method yielded a linear calibration curve in the concentration ranges from 15 to 200 μg/L for the rutin with regression coefficients (r2) of 0.9990. The limits of detection (LODs, S/N=3) and limits of quantification (LOQs, S/N=10) were found to be 8 μg/Land 28 μg/L, respectively. Both the intra-day and inter-day precisions (RSDs) were < 10% .
Conclusion:
The developed approach offered wide linear range, and good reproducibility. Owing to the diverse structures and unique characteristic, GO/TiO2 possesses great potential in the enrichment and analysis of trace rutin in real aqueous samples.
PPT on "Functionalization of Nanoparticles and Nanoplatelets" by Deepak rawalDeepak Rawal
Presentation on Functionalization of nanoparticles, magnetic nanoparticles, chemical funtionalization, funtionalization of carbon nanotubes and their applications. Introduction about graphite nanoplatelets.
characteristics exploration of n ii cuzn nano-composite coated permanent magnetsIJEAB
This paper presents the synthesis of compound using Citrate Precursor Sol- Gel Method and Ball millingfor grinding the compound. X-ray diffraction measurements (XRD) confirmed the formation of single-phase cubic spinel structure. The average crystallite size was calculated using XRD pattern and confirmed by Scanning Electron Microscope (SEM). The electromagnetic properties were investigated using Vector Network Analyzer (VNA) and molar magnetic susceptibility measurements. The magnetic measurements have proved that the entire preparation method has considerable effect in enhancing the magnetic properties of the system. And an application of PMBLDC machine design with ferrite coated permanent magnets having competitive power density and efficiency. The influence of temperature variation on the magnets on the electric machine performance is also observed.
Synthesis, Characterization, Antibacterial and DNA Binding Studies of Mn (II)...IOSRJAC
Mn (II) complex of the Schiff base (L), 3-(2-(2-hydroxy-3-methoxybenzylidene) hydrazinyl) quinoxalin-2(1H)-one (VHQO) was prepared and characterized by IR, UV-VIS, Mass, Elemental analysis, TGDTA, magnetic susceptibility and conductivity measurements. VHQO behaved as monobasic, tridentate ligand and formed 1:2 complex (ML2) with the metal ion (M) coordinating through ring nitrogen, azomethine nitrogen and phenolic oxygen. Thermal analysis of the complex indicated the absence of lattice and coordinated water. Based on the spectral and analytical data, octahedral geometry was assigned to the complex. Antibacterial activity of the complex against gram positive bacteria, Bacillus subtillis, Staphylococcus aureus, and gram negative bacteria, Escherichia coli, Proteus vulgaris, Pseudomonas aeroginosa , and Klebsiella pneumonia was studied. The interaction of the complex with Calf Thymus DNA (CT-DNA) was studied by absorption spectroscopy and the intrinsic binding constant was calculated.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IRJET- Plant Latex Mediated Solution Combustion Synthesis of Mg1-XZNXAl2O4 Na...
Similar to Synthesis and study of structural and magnetic properties of superparamagnetic Fe3O4@SiO2 core/shell nanocomposite for biomedical applications. Article 2, Volume 1, Issue 2, Winter 2014, Page 71-78
Study of magnetic and structural and optical properties of Zn doped Fe3O4 nan...Nanomedicine Journal (NMJ)
Objective(s):
This paper describes synthesizing of magnetic nanocomposite with co-precipitation
method.
Materials and Methods:
Magnetic ZnxFe3-xO4 nanoparticles with 0-14% zinc doping (x=0, 0.025, 0.05, 0.075, 0.1 and 0.125) were successfully synthesized by co-precipitation method. The prepared zinc-doped Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and UV-Vis spectroscopy.
Results:
results obtained from X-ray diffraction pattern have revealed the formation of single phase nanoparticles with cubic inverse spinal structures which size varies from 11.13 to 12.81 nm. The prepared nanoparticles have also possessed superparamagnetic properties at room temperature and high level of saturation magnetization with the maximum level of 74.60 emu/g for x=0.075. Ms changing in pure magnetite nanoparticles after impurities addition were explained based on two factors of “particles size” and “exchange interactions”. Optical studies results revealed that band gaps in all Zn-doped NPs are higher than pure Fe3O4. As doping percent increases, band gap value decreases from 1.26 eV to 0.43 eV.
Conclusion:
These magnetic nanocomposite structures since having superparamagnetic property
offer a high potential for biosensing and biomedical application.
Spinel Ferrite Nanoparticles Synthesis, Characterization and Applicationsijtsrd
Spinel ferrite nanoparticle have attracted a great attention due to its widely used in several areas such as in electronics devices, biomedical, catalyst and wastewater treatment. The synthesis, characterisation and application of spinel ferrite nanoparticles in various fields is focuses in this review paper. The most commonly used synthesis methods along with their advantages and limitations were discussed. The most common characterisation techniques and their applications such as power applications, biomedical applications, inductors, high frequency and Electromagnetic Interference EMI Suppression are briefly reviewed. D. L. Chaudhari | D. S. Choudhary | K. G. Rewatkar "Spinel Ferrite Nanoparticles: Synthesis, Characterization and Applications" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-3 , April 2020, URL: https://www.ijtsrd.com/papers/ijtsrd30684.pdf Paper Url :https://www.ijtsrd.com/physics/nanotechnology/30684/spinel-ferrite-nanoparticles-synthesis-characterization-and-applications/d-l-chaudhari
Physical and Magnetic Properties of Manganese Ferrite NanoparticlesIJERA Editor
In this paper, manganese ferrite (MnFe2O4) nanoparticles were synthesized using chemical bath deposition (CBD) method and characterized by XRD and TEM to determine different properties of nanoparticles. The results obtained showed the formation of manganese ferrite nanoparticles with an average particle size are in good agreement with previous reported experimental results and displayed good magnetic properties. Magnetic properties was determined using Vibrating Sample Magnetometer(VSM). Due to simplicity and low cost of this process, it could be used for synthesis of ferrites nanoparticles. These materials may be used in drug delivery systems, electronic devices and water remediation.
Application of mixed colloidal magnetic fluid of single domain Fe3O4 and NiFe...IJERA Editor
Ferrofluids are stable suspensions of colloidal ferrimagnetic particles in suitable non – magnetic carrier liquids. They have attracted a lot of attention from scientists and engineers due to their many interesting properties and applications in various branches of engineering. The present work reports the performance of colloidal fluid of single domain nanoparticles of NiFe2O4 and Fe3O4. The thermal properties and its dynamics on magnetization as well as its effect on thermal conductivity on the colloidal fluid are studied here. Advantages of the increased thermal conductivity and optimization of magnetization of mixed colloidal fluid is used to extract the heat from voice coil. Nanoparticles of 21 nm of Fe3O4 and 12 nm of NiFe2O4 are used for mixed colloidal fluid. The suspension of particles is achieved by coating the nanoparticles with mono-corboxylic group on both the types of particles. The higher size (21 nm of Fe3O4 and 12 nm of NiFe2O4) particles are taken for synthesizing colloidal fluid, to have magnetic property of mixed colloidal liquid at elevated temperature of voice coil of speaker (Higher sized particles gives better magnetization). Oil is used as a carrier. Mixed magnetic colloidal fluid is used as a medium for damping so that noise is reduced at higher temperature of voice coil
Nanotechnology has become one of the most promising technologies applied in
all areas of science. Metal nanoparticles produced by nanotechnology have
received global attention due to their extensive applications in the biomedical
and physiochemical
fields. Recently, synthesizing metal nanoparticles using
microorganisms and plants has been extensively studied and has been recog-
nized as a green and efficient way for further exploiting microorganisms as
convenient nanofactories. Here, we explore and detail the potential uses of
various biological sources for nanoparticle synthesis and the application of
those nanoparticles. Furthermore, we highlight recent milestones achieved for
the biogenic synthesis of nanoparticles by controlling critical parameters,
including the choice of biological source, incubation period, pH, and
temperature.
Evaluation of mechanical and thermal properties of microwave irradiated poly ...Mukarram Zubair
Poly (styrene-co-methyl methacrylate) (P(S-co-MMA)) was blended with pristine graphene (G) by melt mixing technique and treated under microwave irradiation. The nanocomposites were irradiated for 5 and 10 min at frequency 1245 MHz.
Structure changes in the irradiated nanocomposites were observed by Fourier transform infrared spectroscopy and Raman spectroscopy. The irradiated composites showed a significant increase in the storage modulus i.e. 21% for 0.1% and 31% for
1% graphene polymer composites after 5 min irradiation. However at higher irradiation (10 min), degradation of nanocomposites was observed. The concept of improvement of interfacial interaction between graphene and P(S-co-MMA) chains at 5-min microwave exposure and degradation of nanocomposites at higher irradiation duration was assessed and supported by X-ray diffraction and scanning electron
microscopy.
Polyaniline Clay Nanocomposites Synthesis and Characterizationijtsrd
Nanocomposites of polyaniline PANI with Na montmorillonite clay MMT were synthesized by emulsion polymerization method. Dodecylsulphuric acid DSA served the dual purpose of dopant and emulsifier. Analysis of X ray diffraction results demonstrated the intercalation of PANI DSA between the clay layers at the nanoscale level. The interaction between the intercalated PANI DSA and clay layers was observed from FTIR spectra. The results of thermo gravimetric analysis showed the improved thermal stability of the nanocomposite materials. The dc conductivity was observed in the range 0.033 3.214 Scm 1at room temperature which found to be dependent on the loading of clay and dopant concentration. The morphology of the composite was investigated by scanning electron microscope and the morphology changed with the variation of MMT loading. Madhab Upadhyaya "Polyaniline/Clay Nanocomposites-Synthesis and Characterization" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-4 , June 2022, URL: https://www.ijtsrd.com/papers/ijtsrd49979.pdf Paper URL: https://www.ijtsrd.com/chemistry/polymer-chemistry/49979/polyanilineclay-nanocompositessynthesis-and-characterization/madhab-upadhyaya
Synthesis, Characterization of ZnS nanoparticles by Coprecipitation method us...IOSR Journals
ZnS nanoparticles are prepared by coprecipitation method using various capping agents like PVP (polyvinylpyrrolidone), PVA (polyvinylalcohol) and PEG-4000 (polyethyleneglycol). These are characterized by UV-Visible spectra, X-ray diffraction (XRD) studies, Fourier Transform Infra-red spectra (FTIR) and Transmission electron microscopy (TEM). UV-Visible absorption spectra are used to find the optical band gap and the values obtained have been found to be in the range of 3.80-4.00eV. The particle size of nanoparticles calculated from XRD pattern has been in the range of 2-4 nm. It is also observed that the particle size of nanoparticle is affected by the nature of capping agent. Photo catalytic degradation of xylenol orange (XO) by the nanoparticles shows that these act as photo catalysts under sunlight irradiation. The XO dye was degraded more than 87.24, 83.42 and 73.05% in the presence of PEG-4000, PVA and PVP capped ZnS nanoparticles in 120, 150 and 180 min. respectively. The kinetics of catalyzed by synthesized ZnS nanoparticles with XO dye follows pseudo-first order kinetics with reasonable apparent rate constants.
Synthesis of new dental nanocomposite with glass nanoparticles Article 7, Vol...Nanomedicine Journal (NMJ)
Objective(s):
The aim of this study was to synthesis new dental nanocomposites reinforced with fabricated glass nanoparticles and compare two methods for fabrication and investigate the effect of this filler on mechanical properties.
Materials and Methods: The glass nanoparticles were produced by wet milling process. The particle size and shape was achieved using PSA and SEM. Glass nanoparticles surface was modified with MPTMS silane. The composite was prepared by mixing these silane-treated nanoparticles with monomers. The resin composition was UDMA /TEGDMA (70/30 weight ratio). Three composites were developed with 5, 7.5 and 10 wt% glass fillers in each group. Two preparation methods were used, in dispersion in solvent method (group D) glass nanoparticles were sonically dispersed in acetone and the solution was added to resin, then acetone was evaporated. In non-dispersion in solvent method (group N) the glass nanoparticles were directly added to resin. Mechanical properties were investigated included flexural strength, flexural modulus and Vickers hardness.
Results:
Higher volume of glass nanoparticles improves mechanical properties of composite. Group D has batter mechanical properties than group N. Flexural strength of composite with 10%w filler of group D was 75Mpa against 59 Mpa of the composite with the same filler content of group N. The flexural modulus and hardness of group D is more than group N.
Conclusion:
It can be concluded that dispersion in solvent method is the best way to fabricate nanocomposites and glass nanoparticles is a significant filler to improve mechanical properties of dental nanocomposite.
Plant Mediated Synthesis of ZnO and Mn Doped ZnO Nanoparticles Using Carica P...IIJSRJournal
In this work, Zinc Oxide (ZnO) and Mn-doped ZnO nanoparticles were green synthesized using Carica papaya extract by the Co-precipitation method. X-ray diffraction (XRD) results revealed the formation of ZnO and Mn-doped ZnO nanoparticles with the wurtzite crystal structure (hexagonal). Due to the presence of dopant Manganese (Mn) the optical spectra showed a redshift in the absorbance spectrum. Structural and optical properties of the end product showed that the manganese ions (Mn2+) substituted the Zinc ions (Zn2+) without altering the Wurtzite structure of ZnO. Fourier Transform Infrared Spectroscopy (FTIR) spectra confirm the presence of metal oxide present in the end product. The antibacterial efficiency of ZnO and Mn-doped ZnO nanoparticles were studied using the agar well diffusion method against Gram-positive and Gram–negative bacteria. It is obvious from the results that Mn doped ZnO nanoparticles exhibit better antibacterial activity than ZnO nanoparticles.
Similar to Synthesis and study of structural and magnetic properties of superparamagnetic Fe3O4@SiO2 core/shell nanocomposite for biomedical applications. Article 2, Volume 1, Issue 2, Winter 2014, Page 71-78 (20)
Evaluation of the effect of crocetin on antitumor activity of doxorubicin enc...Nanomedicine Journal (NMJ)
Objective(s): The current study reports investigation of codelivery by PLGA nanoparticles (NPs) loaded with crocetin (Cro), a natural carotenoid dicarboxylicHYPERLINK “http://en.wikipedia.org/wiki/Carboxylic_acid” acid that is found in the crocus flower, and Doxorubicin (DOX).
Materials and Methods: Double emulsion/solvent evaporation method was used for preparation of PLGA nanoparticles containing Dox and Cro. Characterizations of prepared NPs were investigated by atomic force microscopy (AFM) and dynamic light scattering analysis. In vitro Cytotoxicity of DOX and Cro loaded PLGA NPs (PLGA-DOX-Cro) on MCF-7 cell line was evaluated using MTT test. Flow cytometry experiments were implemented to distinguish cells undergoing apoptosis from those undergoing necrosis. Furthermore the expression of caspase 3 was examined by western blot analysis.
Results: The prepared formulations had size of 150- 300 nm. Furthermore, PLGA-DOX-Cro nanoparticles inhibited MCF-7 tumor cells growth more efficiently than either DOX or Cro alone at the same concentrations, as quantified by MTT assay and flow cytometry. Studies on cellular uptake of DOX-Cro-NPs demonstrated that NPs were effectively taken up by MCF-7 tumor cells.
Conclusion: This study suggested that DOX-Cro-NPs may have promising applications in breast cancer therapy.
Effects of combination of magnesium and zinc oxide nanoparticles and heat on ...Nanomedicine Journal (NMJ)
Objective: The objective of this study was to investigate the antibacterial activities of combination of MgO and ZnO nanoparticles in the presence of heat against Escherichia coli and Staphylococcus aureus.
Materials and Methods:Bacteria were grown on either agar or broth media followed by the addition of ZnO and MgO nanoparticles. Then the combined effect of ZnO and MgO nanoparticles was investigated. Furthermore, the media containing nanoparticles were treated with mild heat and their synergistic antibacterial activity was investigated against E. coli and S. aureus in milk.
Results: The data showed that the nanoparticles used in this study had no effect on the bacteria in the agar medium. However, the results showed that ZnO and MgO nanoparticles resulted in a significant decrease in the number of E. coli (P<0.000) and S. aureus (Pd”0.05) in the broth medium. The combination of nanoparticles and mild heat exhibited a significant decrease in the number of E. coli and S. aureus indicating the synergistic effects of nanoparticles and heat.
Conclusion: Using a combination of mild heat, ZnO and MgO nanoparticles, E. coli and S. aureus can be controlled successfully in the milk. Mild heating plus ZnO and MgO nanoparticles has a synergistic effect which would reduce the need for high temperature and also the concentrations of ZnO and MgO nanoparticles required for pathogen control in minimally processed milk during maintaining.
Preparation and evaluation of electrospun nanofibers containing pectin and ti...Nanomedicine Journal (NMJ)
Objective(s):The aim of this study was to prepare electrospun nanofibers of celecoxib using combination of time-dependent polymers with pectin to achieve a colon-specific drug delivery system for celecoxib.
Materials and Methods:Formulations were produced based on two multilevel 22 full factorial designs. The independent variables were the ratio of drug:time-dependent polymer (X1) and the amount of pectin in formulations (X2). Electrospinning process was used for preparation of nanofibers. The spinning solutions were loaded in 5 mL syringes. The feeding rate was fixed by a syringe pump at 2.0 mL/h and a high voltage supply at range 10-18 kV was applied for electrospinning. Electrospun nanofibers were collected and evaluated by scanning electron microscopy and drug release in the acid and buffer with pH 6.8 with and without pectinase.
Results:Electrospun nanofibers of celecoxib with appropriate morphological properties were produced via electrospinning process. Drug release from electrospun nanofibers was very low in the acidic media; while, drug release in the simulated colonic media was the highest from formulations containing pectin.
Conclusion: Formulation F2 (containing drug:ERS with the ratio of 1:2 and 10% pectin) exhibited acceptable morphological characteristics and protection of drug in the upper GI tract and could be a good candidate as a colonic drug delivery system for celecoxib.
The combined effects of Aloe vera gel and silver nanoparticles on wound heali...Nanomedicine Journal (NMJ)
Objective(s): This study was aimed at investigating the synergy effects of Aloe vera gel and silver nanoparticles on the healing rate of the cutting wounds.
Materials and Methods: In order to determine the concentration of silver nanoparticles in Aloe vera gel, the MBC methods were applied on the most common bacteria infecting wounds, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa. The cutting wounds with Full-thickness skin were dorsally created on rats; then the rats were divided into 4 groups. The treatments groups included: mixture of Aloe vera gel and silver nanoparticles, Aloe vera gel alone and silver nanoparticles alone in addition to control groups. The treatment was carried out for 2 weeks and the size of the wound closures were measured by an image software analysis.
Results:There was no significant difference (p<0.05) in healing rate between the control and mixture group. However, there were significant differences between the silver nanoparticles and Aloe vera groups using Tukey’s analysis on the 6th, 8th and 10th days.
Conclusion:The Aloe vera gel increased the rate of wound healing whereas the silver nanoparticles had a delay effect; and when they were mixed, it was similar to the average effect of both Aloe vera gel and silver nanoparticles.
Simultaneous loading of 5-florouracil and SPIONs in HSA nanoparticles: Optimi...Nanomedicine Journal (NMJ)
Objective(s): Over the past two decades, considerable interest has been focused on utilizing biocompatible magnetic nanoparticles (MNPs) for biomedical applications. In this study, production of human serum albumin (HSA) nanoparticles using desolvation technique that were simultaneous loaded with high amounts of superparamagnetic iron oxide nanoparticles (SPIONs) and 5-flourouracil (5-FU) was investigated.
Materials and Methods: 5-FU loading (%) and SPIONs entrapment efficiency (%) were optimized using response surface methodology (RSM). The design expert software used to analyse the interactive effects of pH, 5-FU and SPIONs concentrations.
Results:The optimum conditions found to be pH of 8.2, drug concentration of 1.5 mg/ml and SPIONs concentration of 2.79 mg/ml. Under the mentioned optimum conditions, particles with the size of 111.8 nm, zeta potential of -37.1 mV, 5-FU loading of 15.8% and SPIONs entrapment efficiency of 41.1% were obtained. In vitro cumulative release of 5-FU from the nanoparticles was evaluated in phosphate buffer saline (pH 7.4, 37 °C). Results indicated that 85% of the 5-FU released during 95 h, which revealed a sustained release profile. In addition, Vibrating Sample Magnetometer (VSM) analyses confirmed the superparamagnetic properties of magnetic albumin nanoparticles manufactured under the optimum conditions.
Conclusion: According to the findings,SPIONs and 5-FU loaded HAS nanoparticles arepromising for use as novel targeted delivery system due to proper magnetic and drug release behaviours.
Antimicrobial and cytotoxicity effect of silver nanoparticle synthesized by C...Nanomedicine Journal (NMJ)
Objective(s): For the development of reliable, ecofriendly, less expensive process for the synthesis of silver nanoparticles and to evaluate the bactericidal, and cytotoxicity properties of silver nanoparticles synthesized from root extract of Croton bonplandianum, Baill.
Materials and Methods: The synthesis of silver nanoparticles by plant part of Croton bonplandianum was carried out. The formation of nanoparticles was confirmed by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), XRD and UV-Vis spectrophotometric analysis. The biochemical properties were assayed by antibacterial study, cytotoxicity assay using cancer cell line.
Results: The formation of silver nanoparticles was confirmed by UV-VIS spectroscopic analysis which showed absorbance peak at 425 nm. X-ray diffraction photograph indicated the face centered cubic structure of the synthesized AgNPs. TEM has displayed the different dimensional images of biogenic silver nanoparticles with particle size distribution ranging from 15-40 nm with an average size of 32 nm. Silver particles are spherical in shape, clustered. The EDX analysis was used to identify the elemental composition of synthesized AgNPs. Antibacterial activity of the synthesized AgNPs against three Gram positive and Gram negative bacteria strains like Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa carried out showed significant zones of inhibition. The cytotoxicity study by AgNPS also showed cytotoxicity on ovarian cancer cell line PA-1 and lung epithelial cancer cell line A549.
Conclusion: The present study confirms that the AgNPs have great promise as antibacterial, and anticancer agent.
Investigation of the effect of different parameters on the phase inversion te...Nanomedicine Journal (NMJ)
Objective(s): Nanoemulsions are a kind of emulsions that can be transparent, translucent (size range 50-200 nm) or “milky” (up to 500 nm). Nanoemulsions are adequatly effective for transfer of active component through skin which facilitate the entrance of the active component . The transparent nature of the system and lack of the thickener and fluidity are among advantages of nanoemulsion.
Materials and Methods: In this study, a nanoemulsion of lemon oil in water was prepared by the phase inversion temperature (PIT) emulsification method in which the tween 40 was used as surfactant. The effect of concentration of NaCl in aqueous phase, pH and weight percent of surfactant and aqueous on the PIT and droplet size were investigated. Results: The results showed that with increasing of concentration of NaCl from 0.05 M to 1 M, PIT decrease from 72 to 50. The average droplet sizes, for 0.1, 0.5 and 1 M of NaCl in 25 ºC are 497.3, 308.1 and 189.9 nm, respectively and the polydispersity indexes are 0.348, 0.334 and 0.307, respectively.
Conclusion: Considering the characteristics of nanoemulsions such as being transparent, endurance of solution and droplet size can provide suitable reaction environment for polymerization process used in making hygienic and medical materials.
Mechanism of oxidative stress involved in the toxicity of ZnO nanoparticles a...Nanomedicine Journal (NMJ)
ZnO NPs (zinc oxide nanoparticles) has generated significant scientific interest as a novel antibacterial and anticancer agent. Since oxidative stress is a critical determinant of ZnO NPs-induced damage, it is necessary to characterize their underlying mode of action. Different structural and physicochemical properties of ZnO NPs such as particle surface, size, shape, crystal structure, chemical position, and presence of metals can lead to changes in biological activities including ROS (reactive oxygen species) production. However, there are some inconsistencies in the literature on the relation between the physicochemical features of ZnO NPs and their plausible oxidative stress mechanism. Herein, the possible oxidative stress mechanism of ZnO NPs was reviewed. This is worthy of further detailed evaluations in order to improve our understanding of vital NPs characteristics governing their toxicity. Therefore, this study focuses on the different reported oxidative stress paradigms induced by ZnO NPs including ROS generated by NPs, oxidative stress due to the NPs-cell interaction, and role of the particle dissolution in the oxidative damage. Also, this study tries to characterize and understand the multiple pathways involved in oxidative stress induced by ZnO NPs. Knowledge about different cellular signaling cascades stimulated by ZnO NPs lead to the better interpretation of the toxic influences induced by the cellular and acellular parameters. Regarding the potential benefits of toxic effects of ZnO NPs, in-depth evaluation of their toxicity mechanism and various effects of these nanoparticles would facilitate their implementation for biomedical applications.
Combined effects of PEGylation and particle size on uptake of PLGA particles ...Nanomedicine Journal (NMJ)
Abstract
Objective:
At the present study, relationship between phagocytosis of PLGA particles and combined effects of particle size and surface PEGylation was investigated.
Materials and Methods:
Microspheres and nanospheres (3500 nm and 700 nm) were prepared from three types of PLGA polymers (non-PEGylated and PEGylation percents of 9% and 15%). These particles were prepared by solvent evaporation method. All particles were labeled with FITC-Albumin. Interaction of particles with J744.A.1 mouse macrophage cells, was evaluated in the absence or presence of 7% of the serum by flowcytometry method.
Results:
The study revealed more phagocytosis of nanospheres. In the presence of the serum, PEGylated particles were phagocytosed less than non-PEGylated particles. For nanospheres, this difference was significant (P<0/05) and their uptake was affected by PEGylation degree. In the case of microsphere formulation, PEGylation did not affect the cell uptake. In the serum-free medium, the bigger particles had more cell uptake rate than smaller ones but the cell uptake rate was not influenced by PEGylation.
Conclusion:
The results indicated that in nanosized particles both size and PEgylation degree could affect the phagocytosis, but in micron sized particles just size, and not the PEGylation degree, could affect this.
Synthesis of silver nanoparticles and its synergistic effects in combination ...Nanomedicine Journal (NMJ)
Abstract
Objectives:
Biofilms are communities of bacteria attached to surfaces through an external polymeric substances matrix. In the meantime, Acinetobacterbaumannii is the predominant species related to nosocomial infections. In the present study, the effect of silver nanoparticles alone and in combination with biocides and imipenem against planktonic and biofilms of A. baumannii was assessed.
Materials and Methods:
Minimum inhibitory concentrations (MICs) of 75 planktonic isolates of A. baumannii were determined by using the microdilution method as described via clinical and laboratory standards institute (CLSI). Among all strains, 10 isolates which formed strong biofilms were selected and exposed to silver nanoparticles alone and in combination with imipenem, bismuth ethandithiol (BisEDT) and bismuth propanedithiol (BisPDT) to determine minimum biofilm inhibitory concentrations (MBIC). Subsequently, minimum biofilm eradication concentrations (MBECs) of silver nanoparticles alone and in combination with imipenem against mature biofilm of the isolates were evaluated.
Results:
Results showed that 29.3% of isolates were susceptible to silver nanoparticles and could inhibit the growth and eradicate biofilms produced by the isolates. For this reason, ∑FIC, ∑FBIC and ∑FBEC ≤ 0.05 were reported which shows synergism between silver nanoparticles and imipenem against not only planktonic cells but also inhibition and eradication of biofilms. The results of ∑FBIC >2 indicated to antagonistic impacts between silver nanoparticles and BisEDT/BisPDT against biofilms.
Conclusion:
It can be concluded that silver nanoparticles alone can inhibit biofilm formation but in combination with imipenem are more effective against A. baumannii in planktonic and biofilm forms.
Abstract
Objective(s):
Zinc oxide nanoparticles (ZNP) are increasingly used in sunscreens, biosensors, food additives and pigments. In this study the effects of ZNP on liver of rats was investigated.
Materials and Methods:
Experimental groups received 5, 50 and 300 mg/kg ZNP respectively for 14 days. Control group received only distilled water. ALT, AST and ALP were considered as biomarkers to indicate hepatotoxicity. Lipid peroxidation (MDA), SOD and GPx were detected for assessment of oxidative stress in liver tissue. Histological studies and TUNEL assay were also done.
Results:
Plasma concentration of zinc (Zn) was significantly increased in 5 mg/kg ZNP-treated rats. Liver concentration of Zn was significantly increased in the 300 mg/kg ZNP-treated animals. Weight of liver was markedly increased in both 5 and 300 mg/kg doses of ZNP. ZNP at the doses of 5 mg/kg induced a significant increase in oxidative stress through the increase in MDA content and a significant decrease in SOD and GPx enzymes activity in the liver tissue. Administration of ZNP at 5 mg/kg induced a significant elevation in plasma AST, ALT and ALP. Histological studies showed that treatment with 5 mg/kg of ZNP caused hepatocytes swelling, which was accompanied by congestion of RBC and accumulation of inflammatory cells. Apoptotic index was also significantly increased in this group. ZNP at the dose of 300 mg/kg had poor hepatotoxicity effect.
Conclusion:
It is concluded that lower doses of ZNP has more hepatotoxic effects on rats, and recommended to use it with caution if there is a hepatological problem.
Preparation and evaluation of vitamin A nanosuspension as a novel ocular drug...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
The aim of this study was to prepare a nanosuspension formulation as a new vehicle for the improvement of the ocular delivery of vitamin A.
Material and Methods:
Formulations were designed based on full factorial design. A high pressure homogenization technique was used to produce nanosuspensions. Fifteen formulations were prepared by the use of different combinations of surfactants Tween 80, benzalkonium chloride and Pluronic and evaluated for pH, particle size, entrapment efficiency, differential scanning calorimetry (DSC), stability and drug release. Also, Draize test was used to evaluate the irritation of rabbit eye by formulations.
Results:
All formulations showed a small mean size that is well suited for ocular application. Also it was observed that the particle size decreased with increase in the amount of surfactant. Drug entrapment increased with increasing amount of surfactant. It was shown that initial and final drug release can be controlled by the ratio and the total amount of surfactants, respectively.
Conclusion:
It was concluded that the use of Tween 80 and Pluronic in the formualtions with a proper ratio does not show eye irritation and could be useful to achieve a suitable nanosuspension of vitamin A as a novel ocular delivery system.
A comparative study about toxicity of CdSe quantum dots on reproductive syste...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Medicinal benefits of quantum dots have been proved in recent years but there is little known about their toxicity especially in vivo toxicity. In order to use quantum dots in medical applications, studies ontheir in vivo toxicity is important.
Materials and Methods:
CdSe:ZnS quantum dots were injected in 10, 20, and 40 mg/kg doses to male mice10 days later, mice were sacrificed and five micron slides were prepared structural and optical properties of quantum dots were evaluated using XRD.
Results:
Histological studies of testis tissue showed high toxic effect of CdSe:ZnS in 40 mg/kg group. Histological studies of epididymis did not show any effect of quantum dots in terms of morphology and tube structure. Mean concentration of LH and testosterone and testis weight showed considerable changes in mice injected with 40 mg/kg dose of CdSe:ZnS compared to control group. However, FSH and body weight did not show any difference with control group.
Conclusion:
Although it has been reported that CdSe is highly protected from the environment by its shell, but this study showed high toxicity for CdSe:ZnS when it is used in vivo which could be suggested that shell could contribute to increased toxicity of quantum dots. Considering lack of any previous study on this subject, our study could potentially be used as an basis for further extensive studies investigating the effects of quantum dots toxicity on development of male sexual system.
Functionalization of carbon nanotubes and its application in nanomedicine: A ...Nanomedicine Journal (NMJ)
Abstract
This review focuses on the latest developments in applications of carbon nanotubes (CNTs) in medicine. A brief history of CNTs and a general introduction to the field are presented.
Then, surface modification of CNTs that makes them ideal for use in medical applications is highlighted. Examples of common applications, including cell penetration, drug delivery, gene delivery and imaging, are given. At the same time, there are concerns about their possible adverse effects on human health, since there is evidence that exposure to CNTs induces toxic effects in experimental models. However, CNTs are not a single substance but a growing family of different materials possibly eliciting different biological responses. As a consequence, the hazards associated with the exposure of humans to the different forms of CNTs may be different. Understanding the structure–toxicity relationships would help towards the assessment of the risk related to these materials. Finally, toxicity of CNTs, are discussed. This review article overviews the most recent applications of CNTs in Nanomedicine, covering the period from 1991 to early 2015.
The role of surface charge of ISCOMATRIX nanoparticles on the type of immune ...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
ISCOMATRIX vaccines have now been shown to induce strong antigen-specific cellular or humoral immune responses to a broad range of antigens of viral, bacterial, parasite or tumor. In the present study, we investigated the role of ISCOMATRIX charge in induction of a Th1 type of immune response and protection against Leishmania major infection in BALB/c mice.
Materials and Methods:
Positively and negatively charged ISCOMATRIX were prepared. BALB/C mice were immunized subcutaneously, three times with 2-week intervals, with different ISCOMATRIX formulations. Soluble Leishmania antigens (SLA) were mixed with ISCOMATRIX right before injection. The extent of protection and type of immune response were studied in different groups of mice.
Results:
The group of mice immunized with negatively charged ISCOMATRIX showed smaller footpad swelling upon challenge with L. major and the highest IgG2a production compared with positively charged one. The mice immunized with positively charged ISCOMATRIX showed the lowest splenic parasite burden compared to the other groups. Cytokine assay results indicated that the highest level of IFN- γ and IL-4 secretion was observed in the splenocytes of mice immunized with negatively charged ISCOMATRIX as compared to other groups.
Conclusion:
The results indicated that ISCOMATRIX formulations generate an immune response with mixed Th1/Th2 response that was not protective against challenge against L. major.
Abstract
In the last decade, developments in nanotechnology have provided a new field in medicine called “Nanomedicine”. Nanomedicine has provided new tools for photodynamic therapy. Quantum dots (QDs) are approximately spherical nanoparticles that have attracted broad attention and have been used in nanomedicine applications. QDs have high molar extinction coefficients and photoluminescence quantum yield, narrow emission spectra, broad absorption, large effective stokes shifts. QDs are more photostable and resistant to metabolic degradation. These photosensitizing properties can be used as photosensitizers for Photodynamic Therapy (PDT). PDT has been recommended for its unique characteristic, such as low side effect and more efficiency. Therefore, nanomedicine leads a promising future for targeted therapy in cancer tumor. Furthermore, QDs have recently been applied in PDT, which will be addressed in this review letter. Also this review letter evaluates key aspects of nano-particulate design and engineering, including the advantage of the nanometer scale size range, biological behavior, and safety profile.
Preparation of protein-loaded PLGA-PVP blend nanoparticles by nanoprecipitati...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
Despite of wide range applications of polymeric nanoparticles in protein delivery, there are some problems for the field of protein entrapment, initial burst and controlled release profile.
Materials and Methods:
In this study, we investigated the influence of some changes in PLGA nanoparticles formulation to improve the initial and controlled release profile. Selected parameters were: pluronic F127, polysorbate 80 as surfactant, pH of inner aqueous phase, L/G ratio of PLGA polymer, volume of inner aqueous phase and addition of polyvinylpyrrolidone as an excipient. FITC-HSA was used as a model hydrophilic drug. The nanoparticles were prepared by nanoprecipitation.
Results:
Initial release of FITC-HSA from PLGA-tween 80 nanoparticles (opt-4, 61%) was faster than control (PLGA-pluronic) after 2.30 h of incubation. Results showed that decrease in pH of inner aqueous phase to pI of protein can decrease IBR but the release profile of protein is the same as control. Release profile with three phases including a) initial burst b) plateau and c) final release phase was observed when we changed volume of inner aqueous phase and L/G ratio in formulation. Co-entrapment of HSA with PVP and pluronic reduced the IBR and controlled release profile in opt-19. Encapsulation efficiency was more than 97% and nanoparticles size and zeta potentials were mono-modal and -18.99 mV, respectively.
Conclusion:
In this research, we optimized a process for preparation of PLGA-PVP-pluronic nanoparticles of diameter less than 300 nm using nanoprecipitation method. This formulation showed a decreased initial burst and long lasting controlled release profile for FITC-HSA as a model drug for proteins.
Abstract
Objective(s):
Abdominal adhesions are one of the most important problems, occurring after intra-abdominal surgery in more than 90% of cases. This condition is the leading cause of bowel obstruction, infertility, and abdominal/pelvic pain. Gold nanoparticles (GNPs) have been shown to be non-toxic and exhibit anti-inflammatory, anti-angiogenic and antioxidant activities. The purpose of this study was to determine the effect of intraperitoneal lavage with GNP solutions on the development of postoperative peritoneal adhesion (PPA).
Materials and Methods:
In the current experimental study, thirty-five male Wistar rats were randomly assigned to seven groups of five rats. After a standardized peritoneal injury, GNP solutions in different concentrations (1, 2.5, 5, 10, 50 and 100 ng/ml) were locally administered through nebulization; normal saline (NS) was administered to the control group. Two weeks later, the rats were sacrificed and cecum and peritoneal samples were harvested for histopathological assessment. Blood samples were obtained to determine serum concentrations of inflammatory biomarkers including tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and vascular endothelial growth factor (VEGF).
Results:
The rats treated with GNPs had significantly lower microscopic and macroscopic peritoneal adhesion scores, compared to the control group (P<0.05). Score 5 of macroscopic adhesions was reported in all the rats of the control group, unlike the GNP groups. Furthermore, microscopic adhesions were reported with all rats in the control group, unlike the GNP groups (reported in 0 out of 5 rats in all GNP groups). In addition, serum levels of IL-1β, TNF-α and VEGF underwent no significant changes.
Conclusion:
Compared to the control group, GNPs decreased the severity of peritoneal adhesions, although they did not alter TNF-α, IL-1β or VEGF serum levels.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
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Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
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Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
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Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Synthesis and study of structural and magnetic properties of superparamagnetic Fe3O4@SiO2 core/shell nanocomposite for biomedical applications. Article 2, Volume 1, Issue 2, Winter 2014, Page 71-78
1. Nanomed J, Vol. 1, No. 2, Winter 2014 71
Online ISSN 2322-5904
http://nmj.mums.ac.ir
Original Research
Received: Sep. 29, 2013; Accepted: Nov. 2, 2013
Vol. 1, No. 2, Winter 2014, page 71-78
Received: Apr. 22, 2014; Accepted: Jul. 12, 2014
Vol. 1, No. 5, Autumn 2014, page 298-301
Synthesis and study of structural and magnetic properties of super
paramagnetic Fe3O4@SiO2 core/shell nanocomposite for biomedical
applications
Mitra Helmi Rashid Farimani1,2*
, Nasser Shahtahmassebi1,2
, Mahmoud Rezaee Roknabadi1,2
,
Narges Ghows3
1
Department of Physics, Ferdowsi University of Mashhad, Mashhad, Iran
2
Nanoscience Center, Ferdowsi University of Mashhad, Mashhad, Iran
3
Department of Chemistry, Ferdowsi University of Mashhad, Mashhad, Iran
Abstract
Objective(s): This paper describes coating of magnetite nanoparticles (MNPs) with
amorphous silica shells.
Materials and Methods: First, magnetite (Fe3O4) NPs were synthesized by co-precipitation
method and then treated with stabilizer molecule of trisodium citrate to enhance their
dispersibility. Afterwards, coating with silica was carried out via a sol-gel approach in which
the electrostatically stabilized MNPs were used as seeds. The samples were characterized by
means of X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier
transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM).
Results: The results of XRD analysis implied that the prepared nanocomposite consists of
two compounds of crystalline magnetite and amorphous silica that formation of their
core/shell structure with the shell thickness of about 5 nm was confirmed by TEM images.
The magnetic studies also indicated that produced Fe3O4@SiO2 core/shell nanocomposite
exhibits superparamagnetic properties at room temperature.
Conclusion: These core/shell structure due to having superparamagnetic property of Fe3O4
and unique properties of SiO2, offers a high potential for many biomedical applications.
Keywords: Biomedical applications, Core-shell structure, Magnetite, Silica, Super
paramagnetism
*Corresponding author: Mitra Helmi Rashid Farimani, Department of Physics, Faculty of Science, Ferdowsi
University of Mashhad, Mashhad, Iran.
Tel: +98 9153236076, Email: mi.farimani@gmail.com
2. Synthesis of superparamagnetic core/shell nanocomposite
72 Nanomed J, Vol. 1, No. 2, Winter 2014
Introduction
In recent decade, the integration of
nanotechnology with molecular biology and
medicine has resulted in active developments
of a new emerging research area, nanobio-
technology, which can significantly advances
the current clinical diagnostic and therapeutic
methods (1). In this field, core/shell
nanostructures (the most common type of
multifunctional nanoparticles) are new gene-
ration of nanostructures in nanomedicine that
have combined components with different
functionalities in one single entity and thus
can achieve different tasks simultaneously.
Magnetite (Fe3O4) nanoparticles (MNPs) are
one of the most used structures as a core to
fabricate core/shell systems due to their
strong superparamagnetic properties (2) in
which nanoparticles would have zero
magnetic remanence with a high magnetic
susceptibility. Based on their unique
properties, superparamagnetic nanoparticles
offer a high potential for several biomedical
applications, such as contrast agents in
magnetic resonance imaging (MRI), carriers
for targeted drug delivery, hyperthermia,
magnetic separation in microbiology and
detoxification of biological fluids (3,4).
In the past few years, many kinds of materials
have been discovered for use as a shell
coating around the MNPs, including noble
metals, metal oxides and inorganic silica (5).
Among these coating materials, silica due to
having several unique advantages is one of
the most ideal coating layers: (a) silica
coating prevents magnetic nanoparticles from
aggregation in wide pH ranges and improves
their chemical stability, (b) silica surface is
often terminated by a silanol group that can
react with silane coupling agents for
conjugation with a variety of biomolecules
and specific ligands and (c) the SiO2 layers
possess a good biocompatibility and
hydrophilicity, which are indispensable for
biomedical applications (6,7). Up to date,
several popular methods including co-
precipitation, microemulsion, thermal decom-
position, solvothermal and sonochemical have
been reported for synthesis of MNPs (8)
among which, chemical co-precipitation is the
preferred rote due to its advantages such as
simple and easy processing operation, high
yield of products with superior crystallinity
and magnetic behaviors, low temperature and
time of reaction and utilization of inorganic
reactant (9).
In spite of named benefits, there is a major
shortcoming in using the prepared Fe3O4 NPs
by co-precipitation method as a core to
fabricate core/shell structures: as a result of
large surface to volume ratio, high surface
energy and magnetic dipole-dipole attractions
between the particles, MNPs are highly prone
to aggregation (10).
Therefore, in order to synthesize well-
dispersed silica-coated MN-Ps, surface
modification and stabilization of magnetite
nanoparticles prior to fabrication of the
core/shell nanostructures is necessary.
For example, Chang et all. (11) reported the
formation of silica on the surface of magnetite
NPs stabilized with a surfactant (oleic acid).
One has to consider that although surfactant
stabilized MNPs could used to prepare of
silica-coated MNPs via Stöber sol-gel app-
roach (the most commonly used method for
generate silica coatings on the surface of
MNPs), the obtained composites are usually
stained by surfactants and the coating process
is difficult to control because surfactant
molecules are easy to desorb from MNPs by
alcohol dissolution (12).
To solve this problem, in this paper, we report
a facile approach which is based on using
electro-statically stabilized MNPs as seeds.
For this purpose, the prepared Fe3O4
nanoparticles by co-precipitation method
were firstly coated with stabilizer molecules
of trisodium citrate to enhance their
dispersion in reaction media during the
coating process and then, magnetite-silica
nanocomposite were synthe-sized by using
these electrostatically stab-ilized NPs as seeds
(12) through the Stöber method.
Figure 1 shows schematic presentation of this
process.
3. Helmi Rashid Farimani M, et al
Nanomed J, Vol. 1, No. 2, Winter 2014 73
Figure 1. Schematic presentation of the synthesis process
of magnetite-silica nanocomposite.
Materials and Methods
Materials
Ferrous chloride tetrahydrate (FeCl2.4H2O),
ferric chloride hexahydrate (FeCl3.6H2O),
hydrochloric acid (HCl), ammonia solution
(NH3, 32%), ethanol, trisodium citrate
dehydrate (C6H5Na3O7.2H2O) and tetraethyl
orthosilicate (TEOS) were purchased from
Merck Co. All the chemicals were analytical
grade and were used without further
purification. Deionized water was also used
throughout the experiment.
Synthesis and stabilization of Fe3O4 nanoparticles
Fe3O4 NPs were synthesized by copreci-
pitation method. The typical procedure is as
follow:
First, a 2M solution of NH4OH (alkali source)
was added dropwise into a solution containing
4.54 g FeCl3.6H2O, 1.9 g FeCl2.4H2O and
0.18 ml HCl dissolved in 15 ml deoxygenated
deionized water under vigorous magnetic
stirring and N2 gas protection at a temperature
of 70˚C.
The color of solution turned from orange to
black immediately, due to the formation of
magnetite NPs. Then, after stirring for 30
min, heating of precipitate was allowed to
crystallize completely for another 90 min.
Finally, MNPs were isolated from solution by
applying an external magnetic field and
washed several times with deionized water
and ethanol.
To stabilize Fe3O4 nanoparticles, the obtained
magnetic mud was re-dispersed in 150 ml
trisodium citrate solution (0.5 M) via
ultrasonic irradiation and the reaction mixture
was then stirred for 1h at 80˚C.
Thereafter, the magnetic precipitate was
washed with acetone to remove the excessive
citrate groups and dried under vacuum.
SynthesisofFe3O4@SiO2core/shellnanocomposite
In this step, first, a 2.0 wt% magnetic fluid
(MF) was made by dispersing the citrate-
modified MNPs (MNPs-C) in deionized water
via ultrasonic irradiation and then, the coating
process were carried out by using obtained
MF as seed through the Stöber method.
2 g of the MF was well-dispersed in the
solution containing 40 ml water, 120 ml
ethanol and 2.35 ml ammonia by ultrasonic
vibration for 1 h. TEOS solution was prepared
by addition of 0.1ml TEOS to 20ml ethanol
and subsequently was dropwise added to the
reaction mixture.
Finally, after stirring for 12 h at ambient
temperature, the obtained product was washed
with ethanol and dried under vacuum for 12 h.
Characterizations
The phase purity and crystal structure of the
samples were investigated using Philips
PW1800 X-ray diffractometer with Cu Kα
radiation (λ = 0.154 nm) in the 2θ range of
20-70˚ and 0.04 degree step size.
Transmission electron microscope (TEM,
LEO 912 AB) and Fourier transform infrared
(FT-IR) spectrophotometer (Avatar-370-
FTIR Thermonicolet) were also employed for
the characterization of the samples. Magnetic
measurements were carried out at room
temperature (300 K) by means of vibrating
sample magnetometer (VSM).
Result and Discussion
Morphology and structure study of the synthesized
samples
The crystallinity and phase purity of the
synthesized MNPs were determined by X-ray
diffraction (XRD) (Figure. 2).
4. Synthesis of superparamagnetic core/shell nanocomposite
74 Nanomed J, Vol. 1, No. 2, Winter 2014
Figure 2. X-ray diffraction pattern of Fe3O4 nanoparticles.
As seen, all the characteristic peaks
corresponding to Bragg diffractions of the
crystal planes (220), (311), (222), (400),
(422), (511) and (440) agree with standard
JCPDS (joint committee on powder
diffraction standards) pattern characteristic
peaks of the magnetite cubic inverse spinel
structure (19-0629) which indicates high
phase purity of synthesized nanoparticles.
Moreover, the sharp peaks observed in
Figure. 2 indicate a high degree of
crystallinity for the MNPs. Based on XRD
data, Fe3O4 NPs structural parameters such as
position and width of peaks, crystalline size,
lattice constant and distance between crystal
planes, were calculated by analyzing (311)
and (440) major peaks whose results are
summarized in Table 1. The average
crystalline size was calculated using the
Debye-Scherrer formula (13):
DXRD= k λ
β cosθ⁄ (1)
where k is the grain shape factor (0.94), λ is
the incident X-ray wavelength (1.54 A˚), β is
the full width at half-maximum (FWHM) and
θ is the diffraction angle.
Also, the average value of the lattice constant
was obtained from the following formula:
a= dhkl [ h2
+ k2
+ l2
]
1/2
(2)
where h, k and l are the Miller indexes, and
dhkl is the interplanar spacing (dhkl = λ / 2sinθ)
(2).The average values of crystalline size and
lattice constant were calculated to be 12.75
nm and 8. 315 A˚ by application of (1) and (2)
formulas to the (311) and (440) major
reflection peaks at 2θ= 35.61˚ and 2θ= 62.84˚,
respectively.
Figure 3 shows TEM images together with
size distribution histograms of both the
unmodified MNPs and citrate-modified
MNPs. The average size for MNPs is about
14.29±4.05 nm whilst for MNPs-C is about
15.41±4.11 nm and both of them have
approximately spherical shape. One can see
that there was no significant change in the
size or the morphology alterations of the
MNPs and citrate-modified MNPs.
As observed in Figure. 3(a), despite of their
hydrophilicity, Fe3O4 NPs are extremely
aggregate which is attributed to their large
specific surface area, high surface energy and
magnetization (10).
Therefore, in this work, for the purpose of
well-dispersed silica-coated MNPs synthesis,
stabilizer molecules of trisodium citrate were
used to modify the surface and to stabilize
prepared Fe3O4 NPs prior to coating with
silica.
The citrate molecules, by creating
electrostatic repulsion between nanoparticles
(due to the presence of di-carboxyl (-COO)
groups with negative charge on the surface of
NPs), prevent their aggregation and promote
their dispersion (Figure. 3(b)).
Figure. 3. TEM images of MNPs (a) before and (b) after
surface modification with 0.5M trisodium citrate solution.
5. Helmi Rashid Farimani M, et al
Nanomed J, Vol. 1, No. 2, Winter 2014 75
Figure 4. TEM image of the magnetite-silica core/shell
nanocomposite.
The TEM image of silica-coated MNPs is
shown in Figure. 4. In this figure, two regions
with different electron densities can be
distinguished that confirms formation of
core/shell structure: an electron dense region
which corresponds to magnetic cores and a
less dense and more translucent region
surrounding these cores that is silica coating
shell with thickness of about 5 nm.
Table 1. The obtained structural parameters of XRD
analysis.
FT-IR analysis
In order to testify the presence of the silica
coating and citrate groups on Fe3O4 NPs
surface, FT-IR analysis of synthesized
samples was performed (Figure 5). In Fig.5(a)
the presence of intense absorption bands at
425, 591 and 624 cm-1
wavenumbers which
respectively attributed to Fe-O stretching
vibrations of Fe2+
and Fe3+
ions placed in
tetrahedral sites and Fe3+
ion placed in
octahedral sites, indicates formation of Fe3O4
structure (14). Again observation of these
absorption peaks in citrate-modified and
silica-coated MNPs (Figures. 5(b) and 5(c))
implies that MNPs don'
t change chemically or
physically after surface modification and
coating processes.
Compared to pristine MNPs, appearance of a
new absorption peak in the range of 1307-
1463 cm-1
and also intensification of peak
with 1620 cm-1
wavenumber are observed in
FT-IR spectrum of citrate-modified MNPs,
which are characteristic of the carboxylate. It
indicates that trisodium citrate has been
successfully bonded on the surface of MNPs
(15). In Figure. 5(c), absorption bands at 801
and 1094 cm-1
are also characteristic peaks of
the symmetrical and asymmetrical vibrations
of Si-O-Si bond that attest silica matrix
formation (4).
It must be mentioned that in all FT-IR spectra
demonstrated in Figure. 5, two absorption
bands centered at 1624 and 3432 cm-1
can
also be seen which are related to O-H
stretching vibration of free water molecules
and surface hydroxyl groups or adsorbed
water on samples surface (9,16). All the
aforementioned absorption bands are outlined
in Table 2 with the assignments of the
associated functional groups.
Table 2. FT-IR absorption wavenumbers with the assignments of the associated functional groups.
(hkl)
2θ
(deg.)
FWHM
(deg.)
DXRD
(nm)
a
(A˚)
dhkl
(A˚)
(311) 35.61 0.689 12.6 8.32 2.51
(440) 62.84 0.756 12.9 8.31 1.47
IR Wavenumbers
(cm-1
)
Assignment of
absorption bands
MNPs Citrate-modified MNPs Silica-coated MNPs
425, 591 and 624 419, 584 and 617 464, 590 and 677 υ(Fe-O)
1624 and 3432 1620 and 3432 1610, 1653 and 3270 υ(O-H)
- 1307-1463 1339-1425 υs(-COO-)
- 1620 1610 and 1653 υa(-COO-)
- - 801 υs(Si-O-Si)
- - 1094 υa(Si-O-Si)
6. Synthesis of superparamagnetic core/shell nanocomposite
76 Nanomed J, Vol. 1, No. 2, Winter 2014
Figure 5. FT-IR spectra of: (a) pristine MNPs, (b) citrate-
modified MNPs and (c) Fe3O4@SiO2 nanocomposite.
Magnetic properties analysis
VSM technique was employed to study
magnetic properties of synthesized Fe3O4
NPs and Fe3O4@SiO2 nanocomposite at
room temperature, whose resultant
magnetization curves are shown in Fig. 6.
The magnetization curve indicates
magnetization as a function of applied
magnetic field.
Based on these curves, data related to
coercivity field (Hc), remnant magnetization
(Mr), saturation magnetization (Ms) and
initial magnetic susceptibility (χi), as the
magnetic characteristics of samples were
calculated whose the obtained results are
summarized in Table 3.
In order to calculate the ultimate saturation
magnetization (Ms), the magnetization (M)
was plotted against 1/H (M at 1/H ≥ 0).
From extrapolation of this curve, the
magnitudes of Ms when 1/H ≈ 0, were
obtained of 70 emu/g and 33.80 emu/g for
Fe3O4 NPs and Fe3O4@SiO2
nanocomposite, respectively. The χi =
(dM/dH)H→0 value was also determined
from the magnetization curves by curve-
fitting to the linear portion (H≈0) of data.
The negligibility of Hc (field strength
required to bring the material back to zero
magnetization) and Mr (value of
magnetization at zero field) values in
absence of an external magnetic field (inset
in Figure. 6) indicates that both samples
possess superparamagnetic property at room
temperature although Ms value of
Fe3O4@SiO2 nanocomposite is significantly
less than pristine MNPs.
The reason of observed reduction could be
explained by the presence of diamagnetic
silica shell surrounding MNPs that has
weakened magnetic moment of inner
magnetic core and diminished the inductive
effect of the magnetic field (15, 9).
One of the parameters calculable by
magnetic data is magnetic particle size or
magnetic domain size, Dm, which can be
determined using the following formula
(17):
Dm= [
18 kBT
π ρ
×
χi
Ms
2 ]
1/3
(3)
Where kB is the Boltzmann constant
(1.38ₓ10-23
J/K), T is the absolute
temperature (300K) and ρ is the density of
Fe3O4 (5.18 g/cm3
).
Using the calculated χi (0.1971 emu/g Oe)
and Ms (70 emu/g) values, a magnetic
particle size of 12.25 nm was obtained at
300K for MNPs which is less than that
estimated from TEM images (DTEM = 14.29
nm).
This difference can be attributed to presence
of the canted spins in the surface layers due
to decrease in the exchange coupling which
leads to formation of magnetically dead
surface layers around the magnetic cores
(18).
Table 3. Magnetic characteristics obtained from VSM analysis.
Mr (emu/g) Ms (emu/g) Hc (Oe) χi (emu/g Oe)
Fe3O4 1.11 70 5 0.1971
Fe3O4@SiO2 0.11 33.80 0.74 0.1121
7. Helmi Rashid Farimani M, et al
Nanomed J, Vol. 1, No. 2, Winter 2014 77
Conclusion
In this work, we successfully synthesized
Fe3O4@SiO2 core/shell nanocomposite by a
sol-gel approach, using electrostatically
stabilized magnetite NPs as seeds.
Magnetic and structural properties of the
prepared
Figure 6. Magnetization curves of Fe3O4 NPs ( ■ )
and Fe3O4@SiO2 nanocomposite ( ▲ ) at 300K. Inset:
the enlarged curves from -20 to 20 Oe.
samples were investigated by XRD, TEM,
FT-IR and VSM techniques whose results are
mentioned bellow:
1. The results of XRD analysis imply that the
prepared nanocomposite consists of
crystalline magnetite cores and an amorphous
silica shell that formation of their core/shell
structure was confirmed by TEM images.
TEM images show also improvement in
dispersibility of the MNPs after surface
modification with citrate groups.
2. The presence of the silica coating and
citrate groups on MNPs surface attested from
the FT-IR absorbance peaks.
3. The synthesized magnetite-silica nano
composite exhibits superparamagnetic
behaviour at room temperature although its
Ms value is significantly less than pristine
MNPs.
It is believed that the prepared nanocomposite
with its magnetic potential can be considered
for different biomedical applications.
Acknowledgments
This work was funded by Ferdowsi
University of Mashhad, Mashhad, Iran.
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