The document summarizes research into controlling the shape and size of gold nanoparticles through a seed-mediated chemical synthesis method. It describes using factors like the aging time of gold seeds and concentration of the reducing agent ascorbic acid to obtain different nanoparticle shapes. The researcher was able to support their hypothesis that shape-controlled synthesis is possible using a simple wet-chemistry approach by manipulating these parameters to produce nanoparticles of varying shapes, including cubes.
Curcumin extract nanoparticles: preparation, characterization and antimicrobi...Innspub Net
In recent years, synthesized zinc oxide nanoparticles have been increasingly investigated for different medicinal uses. In the present study, we aimed at the biosynthesis of zinc oxide using a curcumin extract. Although, toxic effects of curcumin derivative and zinc oxide nanoparticles in different concentration have been studied specifically on animal models besides the antibacterial activity of synthesized curcumin extract and zinc oxide nanoparticles. The aim of the study was to synthesize extract combined zinc oxide nanoparticles. Methods: The synthesized nanoparticles and extract were characterized for the particle size distribution, morphology, optical properties and surface charge by using UVvisible spectroscopy, dynamic light scattering (DLS), (TEM) and (SEM). Elemental composition and structural properties were studied by energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction spectroscopy (XRD). Results: The synthesized nanoparticles and curcumin were irregular shape and had a size distribution in the range of 50–100 nm. The in vitro toxicity effects of zinc oxide and extract showed no toxic effect with different concentration with antibacterial effect.
Silver Nanoparticles Synthesis, Properties, Applications and Future Perspecti...iosrjce
Silver nanoparticles (Ag NPs) have gained significant interest due to their unique optical,
antimicrobial, electrical, physical properties and their possible application. The change of energy level from
continuous band to discrete band of Ag NPs with decrease in size of particles gives strong size dependent
chemical and physical properties. Ag NPs show lower toxicity to human health while Ag NPs show higher
toxicity to various micro-organisms. For this reason Ag NPs having scope for medical instruments,
antimicrobial application, products for health care such as scaffolds, burn dressing, water purification,
agriculture uses. Ag NPs can be synthesized by using various methods which is primarily classified into two
type’s namely physical process which includes laser ablation, condensation, evaporation etc. and chemical
process which includes hydrazine, sodium borohydride, green synthesis etc. Among all these methods green
synthesis is non-toxic, eco-friendly and cost effective. In this review paper different synthesis process especially
green synthesis, properties, applications of silver nanoparticles and their recent advances are described. We
also highlight the toxicity and compares Ag NPs with others nanoparticles.
in-organic nanoparticles are the recent advances in the nanotechnology for their targeted drug delivery systems.
Here in this ppt i beifly focoused on the important points regarding the iron oxide nanoparticles,gold nanao particles,silver nanoparticles,and gold nanoparticles.
Forgive my flaws :-)
Perspective of pharmaceutical molecular designPeter Kenny
This document discusses various challenges in drug discovery and design approaches to address them. It begins by outlining difficulties like exploiting weakly linked targets and predicting toxicity. It then provides simplified illustrations of drug behavior and partitioning. The document advocates for pharmaceutical molecular design based on manipulating molecular properties in a hypothesis-driven or predictive manner. It also questions the use of octanol/water partitioning and promotes alternative approaches like considering hydrogen bonding. Overall, the document argues for more systematic hypothesis-driven molecular design and moving beyond traditional metrics like octanol/water partitioning.
This document summarizes a study on the phytochemical-mediated synthesis of gold nanoparticles using the aqueous extract of the seaweed Sargassum ilicifolium. Key findings include:
1) The seaweed extract reduced gold ions (Au+) to gold nanoparticles (Au0) in solution, indicated by a color change to ruby red and characterized using UV-Vis spectroscopy and XRD.
2) FTIR analysis showed that carboxyl and hydroxyl groups in the seaweed mediated reduction and stabilization of the gold nanoparticles.
3) TEM images showed the produced gold nanoparticles were monodisperse and spherical, ranging in size from 2 to 30 nm.
Lipophilicity in the context of molecular designPeter Kenny
I did this talk at Simpósio de Simulação Computacional e Avaliação Biológica de Biomoléculas na Amazônia (SSCABBA) in Belem on 12-Sept-2012. The photograph in the title slide was taken in Asunción.
1) Silver nanoparticles were synthesized using apple fruit extract through a green synthesis method. The apple extract reduced silver ions (Ag+) to form silver nanoparticles (AgNPs).
2) Characterization using UV-Vis spectroscopy, XRD, and TEM confirmed the formation and properties of spherical AgNPs around 20 nm in size with face centered cubic crystal structure.
3) FTIR analysis identified that biomolecules like proteins and ascorbic acid in the apple extract were responsible for reducing Ag+ ions and stabilizing the formed AgNPs.
4) Antimicrobial testing showed the AgNPs had effective antibacterial properties against common bacteria and antifungal activity against tested fungi strains, demonstrating their antim
Curcumin extract nanoparticles: preparation, characterization and antimicrobi...Innspub Net
In recent years, synthesized zinc oxide nanoparticles have been increasingly investigated for different medicinal uses. In the present study, we aimed at the biosynthesis of zinc oxide using a curcumin extract. Although, toxic effects of curcumin derivative and zinc oxide nanoparticles in different concentration have been studied specifically on animal models besides the antibacterial activity of synthesized curcumin extract and zinc oxide nanoparticles. The aim of the study was to synthesize extract combined zinc oxide nanoparticles. Methods: The synthesized nanoparticles and extract were characterized for the particle size distribution, morphology, optical properties and surface charge by using UVvisible spectroscopy, dynamic light scattering (DLS), (TEM) and (SEM). Elemental composition and structural properties were studied by energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction spectroscopy (XRD). Results: The synthesized nanoparticles and curcumin were irregular shape and had a size distribution in the range of 50–100 nm. The in vitro toxicity effects of zinc oxide and extract showed no toxic effect with different concentration with antibacterial effect.
Silver Nanoparticles Synthesis, Properties, Applications and Future Perspecti...iosrjce
Silver nanoparticles (Ag NPs) have gained significant interest due to their unique optical,
antimicrobial, electrical, physical properties and their possible application. The change of energy level from
continuous band to discrete band of Ag NPs with decrease in size of particles gives strong size dependent
chemical and physical properties. Ag NPs show lower toxicity to human health while Ag NPs show higher
toxicity to various micro-organisms. For this reason Ag NPs having scope for medical instruments,
antimicrobial application, products for health care such as scaffolds, burn dressing, water purification,
agriculture uses. Ag NPs can be synthesized by using various methods which is primarily classified into two
type’s namely physical process which includes laser ablation, condensation, evaporation etc. and chemical
process which includes hydrazine, sodium borohydride, green synthesis etc. Among all these methods green
synthesis is non-toxic, eco-friendly and cost effective. In this review paper different synthesis process especially
green synthesis, properties, applications of silver nanoparticles and their recent advances are described. We
also highlight the toxicity and compares Ag NPs with others nanoparticles.
in-organic nanoparticles are the recent advances in the nanotechnology for their targeted drug delivery systems.
Here in this ppt i beifly focoused on the important points regarding the iron oxide nanoparticles,gold nanao particles,silver nanoparticles,and gold nanoparticles.
Forgive my flaws :-)
Perspective of pharmaceutical molecular designPeter Kenny
This document discusses various challenges in drug discovery and design approaches to address them. It begins by outlining difficulties like exploiting weakly linked targets and predicting toxicity. It then provides simplified illustrations of drug behavior and partitioning. The document advocates for pharmaceutical molecular design based on manipulating molecular properties in a hypothesis-driven or predictive manner. It also questions the use of octanol/water partitioning and promotes alternative approaches like considering hydrogen bonding. Overall, the document argues for more systematic hypothesis-driven molecular design and moving beyond traditional metrics like octanol/water partitioning.
This document summarizes a study on the phytochemical-mediated synthesis of gold nanoparticles using the aqueous extract of the seaweed Sargassum ilicifolium. Key findings include:
1) The seaweed extract reduced gold ions (Au+) to gold nanoparticles (Au0) in solution, indicated by a color change to ruby red and characterized using UV-Vis spectroscopy and XRD.
2) FTIR analysis showed that carboxyl and hydroxyl groups in the seaweed mediated reduction and stabilization of the gold nanoparticles.
3) TEM images showed the produced gold nanoparticles were monodisperse and spherical, ranging in size from 2 to 30 nm.
Lipophilicity in the context of molecular designPeter Kenny
I did this talk at Simpósio de Simulação Computacional e Avaliação Biológica de Biomoléculas na Amazônia (SSCABBA) in Belem on 12-Sept-2012. The photograph in the title slide was taken in Asunción.
1) Silver nanoparticles were synthesized using apple fruit extract through a green synthesis method. The apple extract reduced silver ions (Ag+) to form silver nanoparticles (AgNPs).
2) Characterization using UV-Vis spectroscopy, XRD, and TEM confirmed the formation and properties of spherical AgNPs around 20 nm in size with face centered cubic crystal structure.
3) FTIR analysis identified that biomolecules like proteins and ascorbic acid in the apple extract were responsible for reducing Ag+ ions and stabilizing the formed AgNPs.
4) Antimicrobial testing showed the AgNPs had effective antibacterial properties against common bacteria and antifungal activity against tested fungi strains, demonstrating their antim
Some new directions for pharmaceutical molecular designPeter Kenny
I used this talk on visits to International Medical University (Kuala Lumpur), Nanyang Technological University (Singapore) and Novartis Institute for Tropical Diseases (Singapore)
Studies on Biofield Treated p-Dichlorobenzene | Omicsonlinedeeptimishra10
The aim of present study was to evaluate the impact of biofield energy treatment on physical, thermal, and spectroscopic properties of p-dichlorobenzene.
Effect of Solvents on Size and Morphologies Of sno Nanoparticles via Chemical...Editor IJCATR
Stannous oxide (SnO) is an important functional material which contributes to a wide range of applications. In present
study, the SnO nanoparticles were synthesized using different solvents by chemical co-precipitation method. Different morphologies
of SnO nanoparticles have been obtained by different solvents. The size of SnO nanoparticles was estimated by powder X-ray
diffraction (PXRD) pattern and revealed that SnO crystallizes into tetragonal rutile phase. The chemical structural information of the
synthesized nanoparticles was studied by Fourier transform infrared (FTIR) spectroscopy. The prominent UV emission peak was
observed at 358 nm in the luminance spectra, studied by photoluminescence (PL) spectroscopy. The composition of the product SnO
nanoparticles could be determined by X-ray photoelectron spectroscopy (XPS) and the binding energies of O 1s and Sn 3d3/2 have been
found which are centered at 530 and 495 eV, respectively.
Effect of substrate placement in schott vial to hematite propertiesjournalBEEI
In the present study, hematite (α-Fe2O3) nanostructures were deposited on fluorine doped tin oxide (FTO) coated glass substrate using sonicated immersion synthesis method. The effect of FTO glass substrate placement in Schott vial during immersion process was studied on the growth of the hematite nanostructure and its properties. XRD pattern has revealed seven diffraction peaks of α-Fe2O3 for both hematite nanostructures samples attributed to polycrystalline with rhombohedral lattice structure. The surface morphologies from FESEM have shown that the hematite nanostructures were grown uniformly in both samples with FTO conductive layer facing up and down. Hematite sample with FTO facing down exhibits a smaller size of nanorod, 26.7 nm average diameter, compared to the hematite sample that FTO face up with 53.8nm average diameter. Optical properties revealed higher transmittance in the sample with FTO facing down, probably due to smaller size of nanostructure. The optical band gap energy plotted and extrapolated at 2.50eV and 2.55eV for FTO face up and FTO face down hematite samples respectively, presenting the sample with FTO face up has a lower optical bandgap energy.
This document presents a novel method for quantifying surface modifications of glass fibre-reinforced polyester composites exposed to UV radiation. The method involves staining the composites with methylene blue dye after UV exposure. Colour analysis of digital images of the stained composites is then used to assess degradation, as degradation leads to increased dye adsorption and darker staining. The colour changes correlated well with FTIR spectroscopy and microscopy results. The method is presented as being easier, faster and cheaper than traditional analysis techniques for evaluating UV degradation of such composites.
Evaluation of Biofield Treatment on Physical, Atomic and Structural Character...Mahendra Kumar Trivedi
. Present study investigates impact of Biofield treatment on physical and atomic properties of Mn3O4. X-ray diffraction revealed the significant effect of biofield on lattice parameter, unit cell volume, molecular weight, crystallite sizes and densities of treated Mn3O4.
Biosynthesis of Silver Nanoparticles using PlantsIRJET Journal
This document discusses the biosynthesis of silver nanoparticles using various plant leaves, including neem, mango, lemon, and a combination of the three. Silver nanoparticles were successfully synthesized using aqueous extracts of the leaves. The silver nanoparticles were characterized using UV-Vis spectroscopy and SEM analysis. Optimization studies examined the effect of parameters like silver ion concentration, plant extract concentration, pH, and temperature on the synthesis of silver nanoparticles. The studies found that a silver ion concentration of 1mM, plant extract concentration of 1ml, pH of 7, and temperature of 25°C produced the highest yield of silver nanoparticles. The synthesized silver nanoparticles showed antimicrobial activity against both gram-positive and gram-negative bacteria.
The document summarizes research on the synthesis of tin oxide-cobalt oxide nanocomposites using a bottom-up sol-gel method and their effectiveness in treating dye-contaminated simulated wastewater. Specifically, the nanocomposites were used to adsorb tartrazine dye from water under various conditions. Adsorption isotherm models and kinetics equations were employed to analyze the adsorption process. Thermodynamic studies yielded positive values for ΔG° and ΔS°, indicating spontaneity of adsorption. The nanocomposites effectively removed dye and showed potential for industrial wastewater treatment applications.
Evaluation of Biofield Treatment on Physical, Atomic and Structural Character...albertdivis
In Mn3O4, the crystal structure, dislocation density, particle size and spin of the electrons plays crucial role in modulating its magnetic properties. Present study investigates impact of Biofield treatment on physical and atomic properties of Mn3O4.
International Refereed Journal of Engineering and Science (IRJES)irjes
a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
partition coefficients in drug discoveryPeter Kenny
Partition coefficients are commonly used to model drug permeability and solubility. While octanol/water is typically used, it may not fully account for hydrogen bonding abilities. Differences between octanol/water and alkane/water logP values can provide insights into a drug's hydrogen bonding. A ClogPalk model was developed using molecular surface area and functional group perturbations to predict alkane/water logP. Structural relationships between compounds can be used as a framework for molecular design, property prediction, and identifying outliers that suggest new bioisosteres or interesting effects beyond typical models.
BIOSORPTION OF ZINC (II) IONS FROM AQUEOUS SOLUTION USING BORASSUS FLABELLIFE...EDITOR IJCRCPS
The effective removal of heavy metals from the sugar industry effluent among the most important issue of the many industrialized
countries. Removal Zn2+ from aqueous solution where studied using palm fiber. Batch adsorption was performed as a function of
pH, initial metal ion concentration, equilibrium time and bio-sorbent dose. The optimum pH obtained from results found to be 5.
The maximum contact time for the equilibrium concentration is 180 minutes. The biosorbent dose of 6g. The maximum efficiency of
removal of metal ion by bio-mass is 79 %.The results are fit exactly by both Langmuir and freundlich isotherm model.
Keywords: Biomass; Biosorption; Isotherm; Kinetics; Removal of Zinc.
Hydrothermal synthesis and characterization of oneAlexander Decker
The document summarizes research on synthesizing and characterizing one-dimensional ceria nanorods for removing chromium ions from wastewater. Key points:
1) Ceria nanorods were synthesized via a hydrothermal method and characterized using techniques like SEM, TEM, XRD, and BET surface area analysis.
2) The ceria nanorods were 20-40nm in diameter and 200-300nm in length and had a high surface area of 78 m2/g, making them promising for chromium removal.
3) X-ray absorption spectroscopy (XAS) was used to investigate the oxidation states and local structure of ceria nanorods to better understand the surface reaction during chromium removal.
Property-based molecular design: where next? (12-Jun-2015)Peter Kenny
The document discusses property-based molecular design and some challenges in drug discovery. It notes that molecular design aims to control compound behavior through manipulation of molecular properties in a hypothesis-driven or prediction-driven manner. However, toxicity can be unpredictable and measuring free drug concentrations in vivo is difficult. The document also discusses using structural relationships between compounds as a framework for molecular design and analysis of activity and properties, and notes that both hypothesis-driven and prediction-driven approaches have limitations that require further consideration.
Aspects of pharmaceutical molecular designPeter Kenny
Presented at ResearResearch Center for Molecular Medicine of the Austrian Academy of Sciencesch Center for Molecular Medicine of the Austrian Academy of Sciences (CeMM) in July 2014 to a non-chemist audience. Not sure how it worked but it was an enjoyable visit and nobody fell asleep in the talk.
This document summarizes a research study on identifying proteins involved in irreversible fouling in membrane bioreactors (MBRs). Three MBRs with different configurations and operating conditions were used. Analysis showed that more proteins than carbohydrates were extracted from fouled membranes. Amino acid analysis revealed similar proteins in both membranes. Further analysis using SDS-PAGE and 2D-PAGE identified the compositions of fouling proteins. N-terminal amino acid sequencing identified two outer membrane proteins, OprF and OprD, originating from Pseudomonas species. The study provides insight into proteins that cause irreversible fouling in MBRs treating real wastewater.
Passivative effect of polyethylene glycol and carboxylmethly cellulose as cap...Alexander Decker
The document summarizes a study on the effect of polyethylene glycol (PEG) and carboxylmethly cellulose (CMC) as capping agents on the particle size of ZnS nanoparticles synthesized using wet chemical co-precipitation. ZnS nanoparticles were prepared with PEG and CMC and characterized. The estimated crystal sizes from XRD were 3.92 nm for ZnS/PEG and 3.89 nm for ZnS/CMC. The band gaps were blue shifted to 3.76 eV and 3.88 eV respectively. FTIR analysis confirmed interaction of the capping agents with ZnS. CMC was found to be a better capping agent, producing nanoparticles with a larger band gap and smaller size.
This document summarizes a study on developing a new method for manufacturing porous hydroxyapatite (HA) implants with designed internal architectures. Key points:
1. A lost-mold technique was used involving negative molds made via stereolithography and a highly loaded curable HA suspension. This allowed implants with designed channel patterns to be successfully built.
2. Characterization showed the designed channels in the sintered HA implants had diameters between 366-968 μm with standard deviations of 50 μm or less and porosities between 26-52%.
3. The new technique provides controlled pore structure compared to traditional methods and could produce implants tailored for specific bone defect sites.
This document summarizes research on the synthesis of copper nanoparticles through chemical reduction. A variety of copper salts, reducing agents, ligands, and solvents were tested. While color changes indicated reduction occurred in some experiments, UV-Vis analysis did not find evidence of copper nanoparticle formation due to degradation. The most promising results used copper(II) gluconate reduced by Surfonamine-L-100 in propylene carbonate, showing an absorbance peak that could represent large copper nanoparticles. Further optimization of parameters is needed to produce stable copper nanoparticles that can be characterized.
Some new directions for pharmaceutical molecular designPeter Kenny
I used this talk on visits to International Medical University (Kuala Lumpur), Nanyang Technological University (Singapore) and Novartis Institute for Tropical Diseases (Singapore)
Studies on Biofield Treated p-Dichlorobenzene | Omicsonlinedeeptimishra10
The aim of present study was to evaluate the impact of biofield energy treatment on physical, thermal, and spectroscopic properties of p-dichlorobenzene.
Effect of Solvents on Size and Morphologies Of sno Nanoparticles via Chemical...Editor IJCATR
Stannous oxide (SnO) is an important functional material which contributes to a wide range of applications. In present
study, the SnO nanoparticles were synthesized using different solvents by chemical co-precipitation method. Different morphologies
of SnO nanoparticles have been obtained by different solvents. The size of SnO nanoparticles was estimated by powder X-ray
diffraction (PXRD) pattern and revealed that SnO crystallizes into tetragonal rutile phase. The chemical structural information of the
synthesized nanoparticles was studied by Fourier transform infrared (FTIR) spectroscopy. The prominent UV emission peak was
observed at 358 nm in the luminance spectra, studied by photoluminescence (PL) spectroscopy. The composition of the product SnO
nanoparticles could be determined by X-ray photoelectron spectroscopy (XPS) and the binding energies of O 1s and Sn 3d3/2 have been
found which are centered at 530 and 495 eV, respectively.
Effect of substrate placement in schott vial to hematite propertiesjournalBEEI
In the present study, hematite (α-Fe2O3) nanostructures were deposited on fluorine doped tin oxide (FTO) coated glass substrate using sonicated immersion synthesis method. The effect of FTO glass substrate placement in Schott vial during immersion process was studied on the growth of the hematite nanostructure and its properties. XRD pattern has revealed seven diffraction peaks of α-Fe2O3 for both hematite nanostructures samples attributed to polycrystalline with rhombohedral lattice structure. The surface morphologies from FESEM have shown that the hematite nanostructures were grown uniformly in both samples with FTO conductive layer facing up and down. Hematite sample with FTO facing down exhibits a smaller size of nanorod, 26.7 nm average diameter, compared to the hematite sample that FTO face up with 53.8nm average diameter. Optical properties revealed higher transmittance in the sample with FTO facing down, probably due to smaller size of nanostructure. The optical band gap energy plotted and extrapolated at 2.50eV and 2.55eV for FTO face up and FTO face down hematite samples respectively, presenting the sample with FTO face up has a lower optical bandgap energy.
This document presents a novel method for quantifying surface modifications of glass fibre-reinforced polyester composites exposed to UV radiation. The method involves staining the composites with methylene blue dye after UV exposure. Colour analysis of digital images of the stained composites is then used to assess degradation, as degradation leads to increased dye adsorption and darker staining. The colour changes correlated well with FTIR spectroscopy and microscopy results. The method is presented as being easier, faster and cheaper than traditional analysis techniques for evaluating UV degradation of such composites.
Evaluation of Biofield Treatment on Physical, Atomic and Structural Character...Mahendra Kumar Trivedi
. Present study investigates impact of Biofield treatment on physical and atomic properties of Mn3O4. X-ray diffraction revealed the significant effect of biofield on lattice parameter, unit cell volume, molecular weight, crystallite sizes and densities of treated Mn3O4.
Biosynthesis of Silver Nanoparticles using PlantsIRJET Journal
This document discusses the biosynthesis of silver nanoparticles using various plant leaves, including neem, mango, lemon, and a combination of the three. Silver nanoparticles were successfully synthesized using aqueous extracts of the leaves. The silver nanoparticles were characterized using UV-Vis spectroscopy and SEM analysis. Optimization studies examined the effect of parameters like silver ion concentration, plant extract concentration, pH, and temperature on the synthesis of silver nanoparticles. The studies found that a silver ion concentration of 1mM, plant extract concentration of 1ml, pH of 7, and temperature of 25°C produced the highest yield of silver nanoparticles. The synthesized silver nanoparticles showed antimicrobial activity against both gram-positive and gram-negative bacteria.
The document summarizes research on the synthesis of tin oxide-cobalt oxide nanocomposites using a bottom-up sol-gel method and their effectiveness in treating dye-contaminated simulated wastewater. Specifically, the nanocomposites were used to adsorb tartrazine dye from water under various conditions. Adsorption isotherm models and kinetics equations were employed to analyze the adsorption process. Thermodynamic studies yielded positive values for ΔG° and ΔS°, indicating spontaneity of adsorption. The nanocomposites effectively removed dye and showed potential for industrial wastewater treatment applications.
Evaluation of Biofield Treatment on Physical, Atomic and Structural Character...albertdivis
In Mn3O4, the crystal structure, dislocation density, particle size and spin of the electrons plays crucial role in modulating its magnetic properties. Present study investigates impact of Biofield treatment on physical and atomic properties of Mn3O4.
International Refereed Journal of Engineering and Science (IRJES)irjes
a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
partition coefficients in drug discoveryPeter Kenny
Partition coefficients are commonly used to model drug permeability and solubility. While octanol/water is typically used, it may not fully account for hydrogen bonding abilities. Differences between octanol/water and alkane/water logP values can provide insights into a drug's hydrogen bonding. A ClogPalk model was developed using molecular surface area and functional group perturbations to predict alkane/water logP. Structural relationships between compounds can be used as a framework for molecular design, property prediction, and identifying outliers that suggest new bioisosteres or interesting effects beyond typical models.
BIOSORPTION OF ZINC (II) IONS FROM AQUEOUS SOLUTION USING BORASSUS FLABELLIFE...EDITOR IJCRCPS
The effective removal of heavy metals from the sugar industry effluent among the most important issue of the many industrialized
countries. Removal Zn2+ from aqueous solution where studied using palm fiber. Batch adsorption was performed as a function of
pH, initial metal ion concentration, equilibrium time and bio-sorbent dose. The optimum pH obtained from results found to be 5.
The maximum contact time for the equilibrium concentration is 180 minutes. The biosorbent dose of 6g. The maximum efficiency of
removal of metal ion by bio-mass is 79 %.The results are fit exactly by both Langmuir and freundlich isotherm model.
Keywords: Biomass; Biosorption; Isotherm; Kinetics; Removal of Zinc.
Hydrothermal synthesis and characterization of oneAlexander Decker
The document summarizes research on synthesizing and characterizing one-dimensional ceria nanorods for removing chromium ions from wastewater. Key points:
1) Ceria nanorods were synthesized via a hydrothermal method and characterized using techniques like SEM, TEM, XRD, and BET surface area analysis.
2) The ceria nanorods were 20-40nm in diameter and 200-300nm in length and had a high surface area of 78 m2/g, making them promising for chromium removal.
3) X-ray absorption spectroscopy (XAS) was used to investigate the oxidation states and local structure of ceria nanorods to better understand the surface reaction during chromium removal.
Property-based molecular design: where next? (12-Jun-2015)Peter Kenny
The document discusses property-based molecular design and some challenges in drug discovery. It notes that molecular design aims to control compound behavior through manipulation of molecular properties in a hypothesis-driven or prediction-driven manner. However, toxicity can be unpredictable and measuring free drug concentrations in vivo is difficult. The document also discusses using structural relationships between compounds as a framework for molecular design and analysis of activity and properties, and notes that both hypothesis-driven and prediction-driven approaches have limitations that require further consideration.
Aspects of pharmaceutical molecular designPeter Kenny
Presented at ResearResearch Center for Molecular Medicine of the Austrian Academy of Sciencesch Center for Molecular Medicine of the Austrian Academy of Sciences (CeMM) in July 2014 to a non-chemist audience. Not sure how it worked but it was an enjoyable visit and nobody fell asleep in the talk.
This document summarizes a research study on identifying proteins involved in irreversible fouling in membrane bioreactors (MBRs). Three MBRs with different configurations and operating conditions were used. Analysis showed that more proteins than carbohydrates were extracted from fouled membranes. Amino acid analysis revealed similar proteins in both membranes. Further analysis using SDS-PAGE and 2D-PAGE identified the compositions of fouling proteins. N-terminal amino acid sequencing identified two outer membrane proteins, OprF and OprD, originating from Pseudomonas species. The study provides insight into proteins that cause irreversible fouling in MBRs treating real wastewater.
Passivative effect of polyethylene glycol and carboxylmethly cellulose as cap...Alexander Decker
The document summarizes a study on the effect of polyethylene glycol (PEG) and carboxylmethly cellulose (CMC) as capping agents on the particle size of ZnS nanoparticles synthesized using wet chemical co-precipitation. ZnS nanoparticles were prepared with PEG and CMC and characterized. The estimated crystal sizes from XRD were 3.92 nm for ZnS/PEG and 3.89 nm for ZnS/CMC. The band gaps were blue shifted to 3.76 eV and 3.88 eV respectively. FTIR analysis confirmed interaction of the capping agents with ZnS. CMC was found to be a better capping agent, producing nanoparticles with a larger band gap and smaller size.
This document summarizes a study on developing a new method for manufacturing porous hydroxyapatite (HA) implants with designed internal architectures. Key points:
1. A lost-mold technique was used involving negative molds made via stereolithography and a highly loaded curable HA suspension. This allowed implants with designed channel patterns to be successfully built.
2. Characterization showed the designed channels in the sintered HA implants had diameters between 366-968 μm with standard deviations of 50 μm or less and porosities between 26-52%.
3. The new technique provides controlled pore structure compared to traditional methods and could produce implants tailored for specific bone defect sites.
This document summarizes research on the synthesis of copper nanoparticles through chemical reduction. A variety of copper salts, reducing agents, ligands, and solvents were tested. While color changes indicated reduction occurred in some experiments, UV-Vis analysis did not find evidence of copper nanoparticle formation due to degradation. The most promising results used copper(II) gluconate reduced by Surfonamine-L-100 in propylene carbonate, showing an absorbance peak that could represent large copper nanoparticles. Further optimization of parameters is needed to produce stable copper nanoparticles that can be characterized.
This document discusses the chemistry of nanoscale materials including their synthesis, properties, and applications. Key points include:
- Nanoparticles exhibit unusual properties due to their small size such as changes in melting points, optical properties, and surface reactivity.
- Semiconductor nanoparticles known as quantum dots exhibit quantum confinement effects which alter their band gap.
- Common synthetic methods for nanoparticles include chemical reduction, sonochemistry, and electrochemical routes. Stabilization is needed to prevent aggregation.
- Dendrimers can template the synthesis of metal nanoclusters within their cores. Monitoring by UV-vis spectroscopy allows observation of cluster formation.
Introduction to nanoscience and nanotechnologyMazhar Laliwala
The document discusses nanoscience and nanotechnology. It defines nanoscience as the study of structures sized 1-100 nanometers. At the nanoscale, quantum mechanics effects dominate over classical physics and materials exhibit unexpected properties. The document outlines the history of nanoscience concepts and discoveries. It explores size comparisons to illustrate just how small the nanoscale is and discusses challenges in visualizing and working at that scale.
ZnO nanoparticles were synthesized using various methods and characterized. Their toxicity was then evaluated using two photosynthetic microorganisms, Anabaena flos-aquae and Euglena gracilis. The results showed that nanoparticle size, protective coatings, and hydrolysis ratio affected toxicity. ZnO-TOPO nanoparticles caused cell death in both organisms, while ZnO and ZnO-Brij-76 decreased photosynthetic activity initially but activity increased after 10 days for Anabaena flos-aquae. TEM images showed nanoparticle interactions with cell structures. The study provides insights into how nanoparticle properties influence ecotoxicity.
This document provides an introduction to nanotechnology. It begins with definitions of nanoscience and nanotechnology as the study and application of structures and processes at the nanometer scale, around 1 to 100 nanometers. Next, it discusses the tools that enabled nanoscience like the scanning electron microscope and scanning tunneling microscope which allow observation and manipulation of structures at the nanoscale. The document then outlines various nanostructures that exist in nature like biological machines and viruses, as well as man-made nanostructures like carbon nanotubes and buckyballs. It concludes with an overview of methods for building nanostructures including atom-by-atom assembly using scanning probe microscopes, sculpting materials away, and designing for self assembly.
This document provides information about Inakekelo FM, a community radio station based in Mthambothini, Mpumalanga, South Africa. It outlines the station's strategic purpose, mission, values, coverage area, programming, advertising rates, goals and objectives, and details about the municipality it serves. The station aims to be a credible source of information for its community and foster democratic values through relevant content. It broadcasts in IsiNdebele and SiPedi to a rural population of about 245,000 people across a 1530.2 km2 area.
This document discusses the importance of marriage and family in forming faith. It provides several practical strategies for churches to support family faith formation, including: connecting Sunday worship to daily faith practices, using church seasons to provide family resources, utilizing baptisms and marriages to guide couples, building family dimensions into sacrament preparation, making worship child and parent friendly, supporting marriages, and leading by example in their own family lives. The overall message is that the church should equip and partner with families to nurture faith from an early age.
The document outlines the process that the Committee on Public Administration in Quebec follows when conducting oversight mandates based on reports from the Auditor General. The process includes departments submitting action plans, public hearings, the Committee making recommendations, monitoring implementation, and reporting on progress. Since 2010, the Committee has published 5 reports reviewing implementation of over 100 recommendations, finding progress to be satisfactory in over 70% of cases. The process allows for effective parliamentary oversight and measurement of the impact of the Committee's work.
This document summarizes the evolution of best practices for public accounts committees (PACs) based on various studies conducted between 1999-2013. It outlines the traditional Westminster model of PACs and how they have transformed in new and non-Commonwealth countries. PACs are increasingly taking on powers like self-initiating inquiries and considering budget estimates. The document concludes with recommendations for good practices like adequate resources, open hearings, follow up on recommendations, and specialized training for PAC members.
Geraldine GrimesLewis has over 20 years of experience in executive assistant, office management, education, and real estate management roles. She has a diverse professional background working with a large construction company, several Montessori schools, and multi-family property management firms. She is highly organized, adaptable to different work environments, and has a strong record of customer satisfaction.
Nitin G. Solanki has over 15 years of experience in banking and finance. He currently works as a Manager in the Auto Loan product team at HDFC Bank, where he is responsible for business analytics, sales planning, budgeting and forecasting. Previously, he worked at JPMorgan Chase in their global finance operations team conducting audits. He holds an MBA from ITM Mumbai and a B.Com from Mumbai University.
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Nanotechnology is an experimental and engineering technology manipulate at the nanoscale, such as in the field of different compound fabric synthesizing, food processing agriculture processing and as well as in medicinal application. Due to their physical and chemical applications the metal nanoparticles have a great interest in research. A variety of physical, chemical and biological method that can be used for the synthesis of the metal nanoparticle. All the methods have positive advantages as well as some obstruction. In this following review we try to explain recent research on the synthesis and various application of metal nanoparticle. We summarized the different chemical reduction method and briefly explain their application. Vijay Aithekar | Dr. Sangeeta Gautam "A Research Article on Synthesis of Metal Nano Particles by Chemical Reduction Method" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26371.pdfPaper URL: https://www.ijtsrd.com/physics/nanotechnology/26371/a-research-article-on-synthesis-of-metal-nano-particles-by-chemical-reduction-method/vijay-aithekar
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- Factors like temperature, pH, and ion concentrations can influence nanoparticle size, shape, and properties.
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In our study, two different methods were used to determine the size and size distribution of the sliver and selenium nanoparticles via dynamic light scattering (DLS) and scanning electron microscopy (SEM). Background: Nanotechnology dealing with metal and metalloid nanoparticles has been usually applied in nearly each field of science, engineering, and technology including biology and medicine etc due to presence of size and shape dependent unusual physical and chemical properties. In the most recent decade, numerous groups including appreciably developed metal and metalloid nanoparticles based theranostic approaches for the treatment of almost human diseases. Amongst
many nanoparticles, recently silver and selenium nanoparticles have been broadly used in the antimicrobial coatings, textiles, paints, keyboards, engineering, food industry, electronics, cosmetics, bio-sensing, wound dressings, and even in biomedical devices. Methods: In our study, silver nanoparticles were prepared by using the chemical reduction method. Selenium nanoparticles (SeNPs) were synthesized by the chemical reduction of sodium selenite by glutathione (reduced form) and stabilized by bovine serum albumin (BSA). Characterization of silver and selenium nanoparticles samples were analyzed by dynamic light scattering (DLS) and Scanning Electron Microscopy (SEM). Conclusions: Due to characterization by DLS technique, nanoparticles size was found the range of 79.22 nm and 178 nm for Sliver and Selenium Nanoparticles respectively. Sliver nanoparticles shown morphological average size and shape with SEM reveals spherical shape particles with the size of 80.32 nm whereas Selenium nanoparticles shown rod shape particles with the size of 74.29 nm.
1) The document summarizes research on growing a single crystal of sulfamic acid and sodium chloride by slow evaporation solution growth technique. Characterization of the crystal was done through X-ray diffraction, FTIR, melting point and dielectric studies.
2) X-ray diffraction and FTIR analysis confirmed the crystal had an orthorhombic structure similar to sulfamic acid. The melting point of the doped crystal was higher than sulfamic acid alone.
3) Dielectric studies found the doped crystal had a high dielectric constant of 31088, indicating it could be useful for applications like capacitors, insulators and other electric devices. The doping produced a harder, clearer crystal compared to sulf
Gold nanoparticles (AuNPs) are the most stable metal nanoparticles, also called Gold Colloidal nanomaterials that have quasi-dynamic nature.
Their properties include high stability, high surface area, good conductivity, and low toxicity and biocompatibility Useful in biological applications.
Nanoparticles are solid colloidal particles ranging in size from 10 to 1000 nm.
Nanoparticles are made of a macromolecular material which can be of synthetic or natural origin.
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Gold Nano Particles Of Cancer Treatment: A ReviewShrikant Shirole
Gold nanoparticles are emerging as promising agents for cancer
therapy and are being investigated as drug carriers, photothermal
agents, contrast agents and radiosensitisers. Cancer is the disease
caused by an uncontrolled division of abnormal cells in a part of the
body.In this review some various nanotechnology is found the 10 new
technique and treated with all the cancer treatment is beneficial
compare to other cancer therapy.Will the synthesis of various gold
nano particles and find out the gold nano shells, gold nano cages, gold
colloidal nano spheres. Then Nanoparticles can be used to target bio markers or antigens that
are highly specific to Cancer cells.This gold nano particles using the therapy Rheumatoid
arthritis, Alzheimer's disease, Cancer detection. The introduces to the cancer diseases,nano
particles techniques, cancer therapy, then various types of the gold nano particles, propertices
of cancer cells, future scope of cancer treatment, applications, background of cancer
treatment will be discussed.
KEYWORDS: Gold nano particles techniques, cancer treatment, clinical trials.
The current research aimed at fabricating plant extract mediated biosynthesized silver nanoparticles (AgNPs) utilizing thorn extract of Bombax ceiba (TEBC). The synthesized AgNPs was characterized by UV spectroscopy where the surface plasmonic resonance peak (SPR) was located at 222 nm. The scanning electron microscopy (SEM) studies demonstrated that the morphology of fabricated nanomaterials was primarily cylindrical of average size of 20-30 nm with some spindles of size >50 nm. The anti-microbial evaluation against Staphylococcus aureus revealed that AgNPs exhibited notable activity with ZOI of 27.2 mm at MIC of 25 μg/mL. The outcome of this research evidently signified that the biofabricated AgNPs using TEBC may be a new greener approach or technology to formulate anti-bacterial nanodrugs in future.
Bombax ceiba thorn extract mediated synthesis of silver nanoparticles, eva...
SSTP EE
1. Chemical Synthesis of Plasmonic Noble Metal Nanoparticles
Research Question: Can I use different parameters to control the shape of and size of
nanoparticles?
Norah Mubarak
Area of Study: Chemistry
July 2014
Word Count: 3,023
2. Abstract
Nanotechnology holds significant promise for developments in numerous areas such as
biomedicine, drug therapy, cancer research and solar energy. Although promising, shape
controlled synthesis of nanostructures is important, as their shape and size dictate the eventual
applications. In an attempt to improve the efficiency of the chemical synthesis of gold
nanocubes, I used a two-step seed-mediated growth method. I created a growth solution to
reduce the seeds oxidation number from a positive three to a positive one. Following that I
created a seed solution that was mixed into the growth solution which reduced the gold seeds
from a positive one oxidation to a zero oxidation thus creating the nanocrystals. The shape of the
nanocrystal desired however, is dictated by another factor in which I later found to be the
ascorbic acid (reducing agent) concentration that is entered into the growth solution. I
hypothesized that by controlling the seed structure I could obtain different shapes of
nanocrystals. I later found that by manipulating the aging time of the seeds and by using different
concentrations of reducing agent (ascorbic acid) I could obtain different nanoparticle shapes
(Figure 1). My results support our initial hypothesis, proving that shape-controlled synthesis of
metal nanoparticles is possible via a simple wet-chemistry method.
Word Count: 206
4. Introduction
If the size and shape of a nanoparticle is controlled, then the appropriate nanoparticle for
each different application could be developed as desired. Size and shape of a nanoparticle are
determined by multiple factors that were researched such as age time of the gold seeds, and
growth solution reducing agent concentration. My research question is as follows:
“Can a specific factor or factors control seed mediated chemical synthesis and control the shape
and size of the synthesized nanoparticle?”
One application of this research is to assist cancer therapy and help the precision of
drug delivery. In an attempt to improve the efficiency I used shape and size of nanostructures to
dictate what applications I can use it for. Specifically, photodynamic cancer therapy is the
destruction of the cancer cells by laser oxygen which is cytotoxic, the degree in which something
is toxic to living cells. To avoid the side effect of the remaining dye molecules migrating to the
skin and the eyes and making the patient sensitive to daylight exposure is where the nanoparticle
becomes important. So, as an example of the importance, “The kinetics of nanoparticle
biodegradation is an important factor that can control how and where a drug is released,
impacting treatment efficiency as well as potential toxicity to nontarget tissues from nanoparticle
exposure. If nanoparticles given to a patient release a drug before particles can ever get to target
tissue, then we get high toxicity and low effect. Conversely, if particles are drawn to a tissue but
don’t release the drug until long afterward, then we also don’t get the therapeutic effect.”
(Reineke, 2013)
5. The reason gold nanoparticles are used is because they are usually more stable than
silver, when dispersed in aqueous solution. The gold nanoparticle surface unlike that of silver
can be functionalized with a variety of chemical and biological molecules. Plasmon resonance
wavelengths of gold nanoparticles in different shapes and sizes are on average longer than that of
silver nanoparticles. Why the Plasmon resonance of the type of nanoparticle is important is
because depending on how much light it can absorb and its wavelengths, it can be a critical
factor in the nanoparticle synthesis or the use of the nanoparticle after.
Gold nanoparticles are most widely used for applications in both biology and biomedical
engineering due to their unique optical properties. Optical properties and the surfactant CTAB
are used to control shape and size or so it is believed. Optical properties are the result of the
phenomenon called Localized Surface Plasmon Resonance (LSPR). These properties are shown
by the interaction of light with electrons on the gold nanoparticle surface. The particular
wavelength of light where this occurs is strongly dependent on the gold nanoparticle size, shape,
and surface structure. “Oscillating electric fields of a light ray propagating near a colloidal
nanoparticle interact with the free electrons causing a concerted oscillation of electron charge
that is in resonance with the frequency of visible light. These resonant oscillations are known as
surface Plasmon’s.”(Sigmund-Aldrich). In particular, by varying specific parameters I will
synthesize gold nanocubes. This process has been nearly perfected for other metals such as silver
however for gold there is room for improvement.
A dramatic ‘parameter’ that can be used is the way it is synthesized, the two most
common ways to synthesizing nanoparticles, chemical synthesis and photo-induced synthesis.
Chemical synthesis is the more widely used way to synthesize nanoparticles, however to improve
this process the highest yield possible for the researcher should be used and the researcher should
6. try to exceed it by varying the parameters. The difference between chemical synthesis and photo-
induced synthesis is in photo induced synthesis the nanoparticles are synthesized using a halogen
light filter on a halogen lamp that toils with the LSPR of the metal to then continue with
synthesis. In chemical synthesis the nanoparticles are synthesized in a growth solution using
various chemicals and reducing agents to reduce the oxidation of the gold seeds and therefore
synthesize them into the desired shape or size.
Researchers use these processes to try and learn to control the size and shape of the
nanoparticles because learning to do this can help control the yield. The reason for this research
is vaguely because beginning as small as a nanoparticle will lead to achieving the biggest goal.
In my experiment I used chemical mediated synthesis to grow nanoparticles using various
reducing agents, techniques, and apparatuses to synthesize the shape I desired.
Background Information:
A nanoparticle ,a microscopic particle between 1-100 nanometers, that does not consist of
constant physical properties and is an effective medium between bulk materials and
molecular/atomic structures for expanding science technology research.(Sciencedaily.com,2013)
The role of the sodium borohydride in the synthesis is to reduce the gold seeds from a +3
oxidation to +1 oxidation. This reduction takes place in the Cetyltrimethylammonium bromide
(CTABr) concentrated seed solution. The role of the ascorbic acid in the synthesis is to reduce
the gold seeds from a +1 oxidation to a 0 oxidation. This final reduction takes place in the
growth solution where the seeds also synthesize into the desired nanoparticle shape.
A surface active agent (Surfactant) has its name because they are active at different
interfaces (surfaces). Surfactants are used in a multitude of different applications and may be
7. called something different depending on the application/field of study. They are used to lower
the surface tension and protect the nanoparticle from growing a different way than you want it to.
Different surfactants and different surfactant concentrations help control the growth of the
nanoparticles to a specific size or shape.
In using chemical synthesis, one can observe firsthand the color changes that must occur
throughout the process of the experiment for the metal seeds to synthesize correct/accurately.
These color changes occur when the solutions are mixed together or a reducing agent is added
for example because when it is added it reduces other ‘species’ in the solution.
Proposed Growth Model:
(Figure 1)
Xia, Y., Xiong, Y., Lim, B., &Skrabalak, S. E. Angew. Chem. Int. Ed., 2009, 48, 60-103.
8. Figure 1 above shows how the synthesis of nanoparticles takes place. It starts with the
single crystal, in this case gold crystal, and shows the shape it is further synthesized. (This
diagram is an overview of how synthesis generally takes place). However in the diagram, it does
not show how the crystal gets from a single crystalline structure to the desired nanoparticle
shape. In between the single crystal and the desired shape is the process of reduction from a +3
oxidation to a +1 then down to a 0 oxidation number of gold by the time the gold seeds are
entered into the ‘growth solution’. The crystal structure is now a cuboctahedron and for it to
synthesize into the desired shape (shown in this figure as octahedron and cube) it depends on the
parameters used. The synthesis is controlled by many factors however, including the ascorbic
acid concentration, surfactant concentration/type, and the incubation time of the gold seeds in the
seed solution. What happens is, the surfactant (in this experiment Cetyltrimethylammonium
bromide, CTABr) “guides” the gold precursor in the growth solution to grow on specific faces
<111><110><100>. For example, looking at the cuboctahedron in the middle of the diagram you
can see gold <111> and green <100> faces and the gold precursor in the growth solution will
grow off of the cuboctahedron faces like vectors, if you will. And will grow in that specific
direction depending on the different parameters that one will test. As the specific faces continue
to grow they will eventually become one of the two shapes shown in figure 1. The octagonal rod
and bar in the diagram are what would have been the outcome if I furthered my research and
continued to synthesize the particles. In future research, I will attempt to synthesize gold
nanorods and continue my research and test to see if the rods can be altered using the same or
different parameters.
9. VARIABLES:
Control variables:
Amount of nanopure water
Amount of gold precursor
Amount of surfactant (CTABr)
Surfactant concentration (CTABr)
Temperature of water bath
Amount of sodium borohydride (reducing agent; used in creating gold seeds)
Apparatus/Materials:
Required for experiment
Water bath
Centrifuge tubes (50mL & 1mL)
Centrifuge
Scale
Weighing paper
Spatula
Beaker
Graduated cylinder
Crushed Ice
Micropipettes (100μ-1000μL &
1μL-10μL)
Safety Gloves
Safety goggles
Chemicals required for
experiment
Totalquantity required for
experiment
Ascorbic Acid 15.2 mL
Sodium Borohydride (NaBH4) 0.3 mL
Gold Chloride (HAuCl4) 0.925 mL
Cetyltrimethylammonium
bromide (CTABr) 10.15 mL
10. Nanopure water ≈160 mL
Methods:
Making Solutions:
Several solutions were created before beginning the seed mediated synthesis. The first
solution that was created was the sodium borohydride dilution solution. I used 0.38g of stock
sodium borohydride granules and added it to a centrifuge tube that was in a beaker of ice and
contained 10mL of nanopure water although the solution was not capped completely because of
sodium borohydride’s reactive properties. However, the desired solution must be 0.01 Molar and
the solution created was a 0.1 Molar. The next solution that was created used 1mL of the 0.1
Molar solution of sodium borohydride and was added to a centrifuge tube that was inside a
beaker of ice and contained 9mL of nanopure water by means of micro pipette. This created the
desired 0.01 Molar solution by diluting the first solution 10 times. This solution must be made
the day the synthesis will take place.
The second set of solution prepared were the growth solutions. These solutions are all the
same and there is more than one to represent the different age time of the seeds. The four growth
solutions represent 15 minutes, 30 minutes, 45 minutes, and an hour. To create these solutions I
used a stock solution of the surfactant CTABr (0.1M, 6.4 mL) that was been held at room
temperature in a water bath, HAuCl4 (0.01 M, 0.8mL) ,Nanopure water (32mL), and ascorbic
acid (.1M, 3.8mL). Each solution began with 32mL of nanopure water in a centrifuge tube and
the following chemicals were entered by means of micro pipette in the order of CTABr, HAuCl4,
and five minutes before entering the seed solution is when the ascorbic acid is added. The most
11. significant change to look for in the growth solutions is to make sure the color is changed for
yellowish/gold to colorless once the ascorbic acid is added. If the color change does not occur,
one must restart because it means that reduction from a +1 oxidation to a 0 oxidation number
will not occur when the gold seeds are added.
The third solution that was created is the seed solution. This solution was created by
using the following: Fresh NaBH4 (sodium borohydride) (.01M, .3mL) , HAuCl4 (.01m,
.125mL), and CTABr (.1M, 3.75mL). These chemicals were added into a centrifuge tube
containing the CTABr amount (3.75mL) in the following order: HAuCl4 thenNaBH4. After
adding the reducing agent (NaBH4) a color change should occur in the centrifuge tube from
yellowish/gold to brownish/gray. If the color change does not occur the seeds cannot be used for
synthesis. The solution was then capped quickly and tightly then is inverted for 2 minutes then
placed into a water bath at 30.0°C.
Experiment:
1) After seed solution is placed into water bath, begin timer.
2) After 10 minutes have elapsed, add 3.8mL of ascorbic acid into first growth solution and
observe color change.
3) Next I removed 100μL of seed solution and added it to a centrifuge tube that contains
900μL of nanopure water.
4) Once the timer has reached 15 minutes: using a micro pipette take out 200 μL of seed
solution and insert it rapidly into the growth solution. The solution was capped quickly
and tightly then inverted for 10 seconds. The tube was then placed in a water bath
overnight at 30.0 ° C.
12. 5) Repeat for the different times (30 minutes, 45 minutes, and one hour after the seeds have
entered the bath).
6) The next day a color change should be observed (colorless to reddish/purple).
Creating SEM (Scanning electron microscope) imaging samples:
1) Using a micropipette: Enter 1000μL (1mL) of growth solution into 1mL centrifuge tube.
2) Centrifuge at 10,000 rpm for 10 minutes.
3) In the bottom of the tube there should be a pellet. Pour out as much surfactant as possible
without pouring out the pellet.
4) Fill centrifuge tube back up to 1mL with nanopure water.
5) Centrifuge again for 10 minutes at 10,000 rpm.
6) Again there should be a pellet at the bottom of the tube. Pour out as much
surfactant/water as possible without pouring out pellet.
7) Gather, rinse and score a silicon plate strip with a designated number to identify which
growth solution was used.
8) Using a micropipette, pipette out 7μL of the solution that was just centrifuged and drop
onto silicon strip.
9) Repeat with other growth solutions.
10) Once completed with other growth solution place silicon strip(s) in a Petri-dish and place
in a desiccator until taken to imaging.
11) Send to imaging facility with SEM. Analyze the results.
13. Evidence/Results:
Figure 2.
Figure2 . Representative SEM images of plasmonic gold nanoparticles. (A) Nanocubes (B) Nano
octahedral (C)Pseudo-spherical particles: the ones that are composed are strange facets, no well-
defined structure. Bi pyramids and truncated bi pyramids are also seen. (D) Bi-pyramids and
truncated bi-pyramids. In Figure 2, A and B are a representation of an outcome of high yields. C
and D are representations of an outcome of different shapes.
C
BA
D
14. Conclusion/Discussion:
Conclusions:
This experiment has shown both signs of success and weakness. However, in terms of
results, I have several interesting observations to report.
I was able to conclude that shape-controlled syntheses of gold nanocrystals are easily controlled
through careful choice of seed incubation time and reducing agent concentration (ascorbic acid).
Also, that careful manipulations of ascorbic acid concentration yields cubic and octahedral
nanocrystal shapes in high (>80%) yield.
Discussion:
Applications in many different fields such as biomedical engineering, solar energy, and
along with used to help catalyze reactions. The shapes were synthesized using a seed-mediated
method, where the changes of shape were induced by changing a few parameters such as the
ascorbic acid concentration (reducing agent), age time of the seeds, and optimum washing
conditions for SEM imaging (how many times sample was washed. The first shape synthesized
was the nanocube (synthesized in a sodium borohydride solution along with CTAB, and gold
chloride). Such monodisperisty, which is a polymer system that is homogeneous in molecular
weight, that is, it does not have a distribution of different molecular-weight chains within the
total mass (McGraw-Hill,2003 ),(Figure 2 A) and single crystalline is very important. The best
results shown were in between 30-45 minutes of the CTABr concentrated seed solution. Gold
octahedrons were obtained by changing the ascorbic acid concentration (Figure 2 B). This shape
was synthesized under the same conditions, and the best results came from the 30 minute aged
15. CTABr concentrated growth solution. Bi-pyramids and truncated bi pyramids are formed when a
synthesis does not go to completion to the shape desired (Figure 2 C&D).
There are many factors that can affect the chemical synthesis such as speed the solution
is added, and the way it is entered (drops, all at once, etc.). The chemical synthesis takes place in
the growth solution where the ascorbic acid has reduced the gold precursor from a +3 oxidation
to a +1. Once the gold Nano seeds that are in the seed solution are entered into the growth
solution, the gold cations in the growth solution bombard the gold seed and begin to grow in
different directions creating the optimum shape desired. The concentration of the surfactant will
decide in which direction the seed will grow, in this experiment I used a 0.1 M CTABr.
Various nano particles with simple procedures were formed simply by changing the
concentration of the reducing agent (ascorbic acid) in the CTABr growth solution. Assuming the
number of nano particles before and after the seed mediated growth reaction stayed constant then
the synthesis would have been able to go to completion. The reason a reluctant such as ascorbic
acid helps tailor the final (found in CTAB growth solution) shape is because it pushes cations
onto a specific surface. The other important reducing agent, sodium borohydride, (found in
CTABr concentrated gold seed solution) completes the oxidation from a +1 to a 0 charge. The
role of the reductant is to push the atoms on to the surface of the seed. Because if something is
forced onto it and grows from every corner than you will just get bigger particles if it grows from
every side and it will result in a bigger nanospheres. The point of the growth solution is to create
an environment to allow seeds to grow because being able to control the evolution of seeds is the
point of separate solutions.
As seen in the figures above you get a distribution of structures at time although we try to
16. create an environment to lower their surface energy so we can tailor the final shape of the
particle. We get a distribution of crystalline structures and when added to the growth solution
metal becomes deposited onto it.
Improvements:
Some improvements that could be made are changing some parameters in the experiment
to see if the different outcomes are better than the one I was initially trying to reach which was to
learn to control the shape and size.. Such parameters that I would change are: using different
concentrations of surfactant to see if it affected the synthesis of the nanoparticles and how. As
well as, I would like to try to use different surfactants in the synthesis to see how it affects the
nanoparticle outcome seeing that the surfactant does play a tremendous role in the outcome of
the nanoparticle shape.. So forth, I would like to experiment with photo-induced synthesis and
compare the results of the nanoparticles to those synthesized using chemical synthesis.
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