Nanotubes de carbon jurp


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Nanotubes de carbon jurp

  1. 1. Nanotubes Presentation  1. Carbon Nanotubes By Bryan Sequeira Bertug Kaleli Murshed Alam Farooq Akbar Zac Lochner  2. What are Carbon Nanotubes ?Carbon nanotubes are fullerene-relatedstructures which consist of graphenecylinders closed at either end with capscontaining pentagonal rings
  2. 2.  3. Caps* Typical high resolution TEM image of a nanotube cap  4. DiscoveryThey were discovered in 1991 by the Japanese electron microscopist Sumio Iijima who was studying the material deposited on the cathode during the arc-evaporation synthesis of fullerenes. He found that the central core of the cathodic deposit contained a variety of closed graphitic structures including nanoparticles and nanotubes, of a type which had neverpreviously been observed  5. Carbon Nanotubes:• This is a nanoscopic structure made of carbon atoms in the shape of a hollow cylinder. The cylinders are typically closed at their ends by semi-fullerene-like structures. There are three types of carbon nanotubes: armchair, zig-zag and Chiral (helical) nanotubes. These differ in their symmetry. Namely, the carbon nanotubes can be thought of as graphene planes rolled up in a cylinder (the closing ends of carbon nanotubes cannot be obtained in this way). Depending on how the graphene plane is cut before rolled up, the three types of carbon nanotubes are obtained. Within a particular type, carbon nanotubes with many different radii can be found (depending on how large is the graphene area that is folded onto a cylinder). These tubes can be extremely long (several hundreds of nanometers and more). Some consider them as special cases of fullerenes. When produced in materials, carbon nanotubes pack either in bundles (one next to another within a triangular lattice) - single-walled carbon nanotubes, or one of smaller radius inside others of larger radii - multi-walled carbon nanotubes. Carbon nanotubes have already found several technological applications, including their application in high- field emission displays. Carbon nanotubes were discovered by Sumio Ijima in 1991.  6. The way tofind out howthe carbonatoms arearranged in amolecule canbe done byjoining thevectorcoordinatesof the atoms.By this way itcan beidentifiedwhether if thecarbonatoms arearranged in azig-zag, armchair or in ahelicalshape.  7. Nanotubes are formed by rolling up a graphene sheet into a cylinder and capping each endwith half of a fullerene molecule.Shown here is a (5, 5) armchair nanotube (top), a (9, 0) zigzagnanotube (middle) and a (10, 5)chiral nanotube. The diameter of the nanotubes depends on the values of n and m.  8. Process in ARC discharge• Carbon is vaporized between two carbon electrodes• Small diameter, single-wall nanotubes can be synthesized using a Miller XTM 304 dc arc welder to maintain the optimal settings between two horizontal electrodes in helium or argon atmospheres.• The voltage is controlled by an automatic feedback loop that senses the voltage differences between the two electrodes and adjusts them accordingly.  9. Laser VaporizationConsist of three parts:•Laser•Optical Delay: The optical delay is used todelay mostly the 1064nm when in use withanother line• Reactor  10. Arc discharge method Chemical vapor Laser ablation deposition (vaporization)Connect two graphite rods to a Place substrate in oven, heat Blast graphite with intense power supply, place them to 600 C, and slowly add a laser pulses; use the laser millimeters apart, and throw carbon-bearing gas such as pulses rather than electricity to switch. At 100 amps, carbon methane. As gas decomposes generate carbon gas from vaporizes in a hot plasma. it frees up carbon atoms, which the NTs form; try various which recombine in the form of conditions until hit on one that NTs produces prodigious amounts of SWNTs Can produce SWNT and Easiest to scale to industrial Primarily SWNTs, with a large MWNTs with few structural production; long length diameter range that can be defects controlled by varying the reaction temperature Tubes tend to be short with NTs are usually MWNTs and By far the most costly, because random sizes and directions often riddled with defects requires expensive lasers  11. Uses of Carbon NanoTubes• Since discovering them more than a decade ago, scientists have been exploring possible uses for carbon nanotubes, which exhibit electrical conductivity as high as copper, thermal conductivity as high as diamond, and as much as 100 times the strength of steel at one-sixth the weight. In order to capitalize on these properties, researchers and engineers need a set of tools -- in this case, chemical processes like pyrolytic fluorination -- that will allow them to cut, sort, dissolve and otherwise manipulate nanotubes.• Molecular and Nanotube Memories Nanotubes hold promise for non- volatile memory; with a commercial prototype nanotube-based RAM predicted in 1-2 years, and terabit capacity memories ultimately possible. Similar promises have been made of molecular memory from several companies, with one projecting a low-cost memory based on molecule-sized cylinders by end 2004 that will have capacities appropriate for the flash memory market. These approaches offer non-
  3. 3. volatile memory and if the predicted capacities of up to 1Tb can be achieved at appropriate cost then hard drives may no longer be necessary in PCs.  12. Laser applications heat up for carbon nanotubes• Carbon nanotubes---tiny cylinders made of carbon atoms---conduct heat hundreds of times better than todays detector coating materials. Nanotubes are also resistant to laser damage and, because of their texture and crystal properties, absorb light efficiently. Nanoelectronics• Nanotubes are either conducting or semi-conducting depending upon their structure (or their twist) so they could be very useful in electronic circuitry. Nanotube Ropes/Fibers: These have great potential if the SWNTs can be made slightly longer they have the potential to become the next generation of carbon fibers. Carbon nanotubes additionally can also be used to produce nanowires of other chemicals, such as gold or zinc oxide. These nanowires in turn can be used to cast nanotubes of other chemicals, such as gallium nitride. These can have very different properties from CNTs - for example, gallium nitride nanotubes are hydrophilic, while CNTs are hydrophobic, giving them possible uses in organic chemistry that CNTs could not be used for.• Display Technologies Nanomaterials will help extend the range of ways in which we display information. Several groups are promising consumer flat screens based on nanotubes by the end of 2003 or shortly after (Carbon nanotubes are excellent field emitters). E-paper is another much heralded application and nanoparticles figure in several approaches being investigated, some of which promise limited commercialization in the next year or two. Soft lithography is another technology being applied in this area. •Carbon nanotube fibers under an electron microscope  13. • Light Emitting Polymer Technology Light Emitting Polymer technology is leading to a new class of flat panel displays. Researchers have discovered that Light Emitting Diodes (LEDs) could be made from polymers as well as from traditional semiconductors. It was found that the polymer poly p- phenylenevinylene (PPV) emitted yellow-green light when sandwiched between a pair of electrodes. Initially this proved to be of little practical value as it produced an efficiency of less than 0.01%. However, by changing the chemical composition of the polymer and the structure of the device, an efficiency of 5% was achieved, bringing it well into the range of conventional LEDs. Some Amazing facts and Applications• Carbon Nanotubes possess many unique and remarkable properties (chemical, physical, and mechanical), which make them desirable for many applications. The slender proportions of carbon nanotubes hide a staggering strength: it is estimated that they are 100 times stronger than steel at only one sixth of the weight - almost certainly the strongest fibres that will ever be made out of anything - strong enough even to build an elevator to space. In addition they conduct electricity better than copper and transmit heat better than diamond.• Enhancements in miniaturization, speed and power consumption, size reduction of information processing devices, memory storage devices and flat displays for visualization are currently being developed• The most immediate application for nanotubes is in making strong, lightweight materials. It will be possible to build a car that is lighter than its human driver, yet strong enough to survive a collision with a tank• Aircraft built with stronger and lighter materials will have longer life spans and will fly at higher temperatures, faster and more efficiently. Nanotubes are being explored as receptacles - storage tanks - for hydrogen molecules to be used in the fuel cell that could power automobiles of the future. Hydrogen does not produce pollution or greenhouse emissions when burned and is considered to be the clean energy of the future.  14. Some applications of Carbon• Nanotubes include the following Micro-electronics / • Nanotube actuator semiconductors Molecular Quantum wires Conducting Composites Hydrogen Storage Controlled Drug Noble radioactive gas storage Delivery/release Solar storage Artificial muscles Waste recycling Supercapacitors Electromagnetic shielding Batteries Dialysis Filters Field emission flat panel Thermal protection displays Nanotube reinforced Field Effect transistors and composites Single electron transistors Reinforcement of armour and Nano lithography other materials Nano electronics Reinforcement of polymer Doping Avionics Nano balance Collision-protection materials Nano tweezers Fly wheels" Data storage Magnetic nanotube Nanogear  15. Picture of Carbon NanoTubes  16. Future Uses of CNTs• Nano-Electronics – Nanotubes can be conducting or insulating depending on their properties • Diameter, length, chirality/twist, and number of walls – Joining multiple nanotubes together to make nanoscale diodes – Max Current Density: 10^13 A/cm^2
  4. 4.  17. The Space Elevator• The Idea – To create a tether from earth to some object in a geosynchronous orbit. Objects can then crawl up the tether into space. – Saves time and money• The Problem – 62,000- miles (100,000-kilometers) – 20+ tons  18. The Space ElevatorPictures from  19. The Space Elevator• The Solution: Carbon Nanotubes – 10x the tensile strengh (30GPa) • 1 atm = 101.325kPA • 10-30% fracture strain• Further Obstacles – Production of Nanofibers • Record length 4cm – Investment Capital: $10 billion
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  6. 6. Follow Applications of carbon nanotubes by Nitin Patel on May 30, 2013 Applications of carbon nanotubes Presentation Transcript  1. APPLICATIONS OF CARBON NANOTUBESFOR DRUG DELIVERYSYSTEMSPRESENTED BY :MURTAZA PUTLIWALAM.PHARM, SGSITS  2. INTRODUCTION Carbon nanotubes are cylindrical carbon molecules haveNovel properties. They can be about 1/50,000th the thickness of a humanhair. Their unique surface area, stiffness, strength andresilience have led to much excitement in the field ofpharmacy. High Thermal conductivity. Excellent electron emission characterstics. Good candidates for a wide variety of applications,including drug transporters, new therapeutics, deliverysystems and diagnostics.  3. STRUCTURE OF CARBON NANOTUBES Carbon nanotube (CNT ; also known as buckytubes) is anallotrope of Carbon that is Graphite , in which Carbon atomhave sp2 hybridized state. Nanotubes are cylindrical fullerenes. CNT, which have been constructed with length-to-diameterratio of up to 132,000,000:1. Diameters of the carbon nanotubes have ranging from 2 nm to55 nm. The lengths of CNT are typically several microns. Configurationally it is twodimensional graphene (a singlesheet of graphite ) sheet rolledup with continuous unbrokenhexagonal mesh into acylindrical tube.  4. GEOMETRY OF CARBON NANOTUBESARMCHAIR ARRANGEMENT ZIGZIG ARRANGEMENTCHIRAL ARRANGEMENT  5. TYPES OF CARBON NANOTUBES1. SINGLE WALLED NANOTUBES : The diameter of single-wallednanotubes (SWNTs) has approximatelyto 1 nanometer. SWNT are wrapping with layer ofgraphite which one-atom-thick layercalled graphene into a seamlesscylinder. It requires catalyst for their synthesis. Less accumulation in the body.  6. CONTD…2. MULTIPLE WALLED NANOTUBES : Multi-walled nano tubes (MWNT)consist of multiple rolled layers(concentric tubes) of graphite. It has very complex structure It can be produced without catalyst. Purity of product is high. More chances for accumulation in thebody.  7. Synthesis of Carbon NanotubeVarious Techniques have been developed to producenanotubes in sizeable quantities, which includs :1. Arc discharge2. Laser ablation3. Chemical vapor deposition (CVD).  8. Arc Discharge Method• It is the first macroscopicproduction of carbonnanotubes.• Its cost very high and givesyield up to 30 – 90 %• During this process, the carboncontained in the negativeelectrode sublimates becauseof the high dischargetemperatures.• At 100 amps, carbon vaporizesand forms hot plasma.  9. Chemical Vapor Deposition (CVD) The catalytic vapor phase deposition of carbonwas first reported in 1959 . Most economical method due to cheapest sourceof material i.e Fossil hydrocarbon and gives yieldupto 20-100%•During CVD, a substrate is prepared with a layer ofmetal catalyst particles, most commonly nickel,cobalt, iron, or a combination.•The diameters of the nanotubes that are to begrown are related to the size of the metal particles.•Nanotubes grow at the sites of the metal catalyst;the carbon-
  7. 7. containing gas is broken apart at thesurface of the catalyst particle, and the carbon istransported to the edges of the particle, where itforms the nanotubes.  10. Laser Ablation Method• In the laser ablation process, a pulsed laser vaporizes a graphite targetin a high-temperature reactor .• A water-cooled surface may be included in the system to collect thenanotubes.• The laser ablation method yieldsaround 70% and producesprimarily single-walled carbonnanotubes with a controllablediameter determined by thereaction temperature.• it is more expensive than eitherarc discharge or chemical vapordeposition.  11. FUNCTIONALIZATION OF CARBON NANOTUBES FORBIOLOGICAL APPLICATIONS:• Raw carbon nanotubes have highly hydrophobicsurfaces, and are not soluble in aqueous solutions.• For biomedical applications, surface chemistry orfunctionalization is required to solubilize CNTsimprove biocompatibility and low toxicity.• Two type of Surface fuctionalization of carbonnanotubes :CovalentNoncovalent• Surface fuctionalization of carbon nanotubes  12. Covalent fuctionalization• By attaching hydrophilic polymers such as poly ethylene glycol(PEG) to oxidized CNTs, yielding CNT-polymer conjugatesstable in biological environments.• Covalently PEGylated SWNTs synthesized by this strategy forboth In vitro and in vivo applications.Non Covalent fuctionalization• NCF of CNTs can be carried out by coating CNTs with amphiphilicsurfactant molecules or polymers.• NCF of SWNTs by PEGylated phospholipids (PL-PEG) high watersolubility of nanotubes and versatile functionalities Phospholipidsare the major component of cell membranes, and are safe to use inbiological systems.  13. APPLICATIONS OF CNTsA) Carbon Nanotube Membranes for TransdermalDrug DeliveryB) CNT’S for cancer treatmentC) CNTs for Cardiac Autonomic RegulationD) CNTs for platelet activationE) CNT for tissue regenerationF) Carbon Nanotubes in Drug Delivery: Future Trends  14. Carbon Nanotube Membranes forTransdermal Drug Delivery• Transdermal systems are attractive methods of drug administrationspecifically when treating patients for drug addiction such as nicotine forsmoking cessation.• Through the use of functionalized carbon nanotube (CNT) membranes,drug delivery to the skin can be controlled by applying a small electricalbias to create a programmable drug delivery system.• a transdermal patch system that can be tailored to an individual’s needswill increase patient compliance as well as provide much more effi cienttherapy.  15. CNT’S for cancer treatment• CNT’s can be considered as antitumor agents and when incombination with conventional drugs, can significantly enhance theirchemotherapeutic effect with the help of the advanced drug deliverysystem.• It has been reported that Paclitaxel loaded PEG-CNT’s are promisingfor cancer therapeutics.• There are three key features of this nanoscale drug delivery system(DDS):1. Use of functionalized SWCNTs as a biocompatible platform forthe delivery of therapeutic drugs or diagnostics.2. Conjugation of prodrug modules of an anticancer agent that isactivated to its cytotoxic form inside the tumor cells uponinternalization and in situ drug release.3. Attachment of tumor- recognition modules to the nanotubesurface (binding EGFR antibody)  16. Mechanism by which CNTs enter cells• Incorporation of the drug Either by :– Loading into hollow CNT– Attaching at their outer surface Attachment of the anticancer drug to the outer surface of the CNT canbe through either covalent or noncovalent bonding. CNT with a diameter of 80 nm can be loaded up to 5 million drugmolecules.These are : Passive diffusion of CNTs through the lipid bilayers of the cell membrane Attachment of CNTs to the external cell membrane, resulting in its absorption by thecell using an energy-dependent process, such as Pinocytosis. Endocytosis : Engulfing of CNTs directly by cell.  17. Summary of Anticancer drug delivery via carbon nanotubesCNTType ofcancer/disease In vivo/in vitro Drug Method of loadingSWCNTs Ovarian cancer NA Gemcitabine Use of external forces to particles in aselected directionSWCNTs Leukemia In vitro Daunorubicin Daunorubicin incubated in phosphate-buffered saline at 37°C for 16 hours withSWCNTsSWCNTs Breast cancer In vitro and inmicePaclitaxel Paclitaxel was modified by succinicanhydride, adding a carboxyl group atthe C-2-OH position SWCNTs withbranched PEG-NH2MWCNTs Human gastriccarcinomaIn vitro and inmiceHCPT(10-hydroxycamptothecin)HCPT is linked to MWCNTs usingdiaminotriethylene glycol (hydrophilicspacer) biocleavable ester linkageSWCNTs Chorio-
  8. 8. ,nasopharyngealepidermoidtesticularcarcinomaIn vitro Platinum (IV) The SWCNT-PL-PEG-NH2 was initiallyformed. The SWCNT coated with PEGwas then reacted with the platinum inthe presence of coupling agentsincluding EDC (1-ethyl-3-(3-dimethylaminopropyl) carbodiimidehydrochloride)and NHS  18. Summary of Anticancer drug delivery via carbon nanotubesCNTType ofcancer/disease In vivo/in vitro Drug Method of loadingSWCNTs52 CervicalcancerIn vitro siRNA SWCNTs reacted with PL- PEG. For theincorporation of disulfide bond, the amide groupof PEG was attached to a heterobifunctionalcrosslinker (sulfo-LC-SPDP). The siRNA was thenattached to SWCNTs via a disulfide bondSWCNTs43 Lymphoma In mice Doxorubicin SWCNTs were sonicated in a solution of PL-PEGfollowed by centrifugation. Excess surfactant wasremoved by filtration and washing. Doxorubicinloading onto pegylated SWCNTs was carried out bymixing.MWCNs51 Breast cancer In vitro Methotrexate Amine-MWCNTs was generated through 1,3-dipolar cycloaddition reaction of zomethineylides.Methotrexate was reacted with f-MWCNTsthrough coupling agents, ie, HATU and DIEA  19. CNTs for Cardiac AutonomicRegulation• There are single-walled carbon nanotubes used in thecardiac autonomic regulation.• Single-walled carbon nanotubes are portion ofphysicochemical properties with fine component whichmay damage cardiovascular autonomic control thatproved after the study in rats.• SWCNTs may alter the baroreflex function, then affectingthe autonomic cardiovascular control regulation  20. CNTs for platelet activation• SWCNTs using alongwith platelet P-selectin when injected intoanaesthetized mice, light dye induced thrombus formationwas found and the platelet found to be activated.• Activate blood platelets by inducing extracellular Ca2+ influxthat could be inhibited by calcium channel blockers.  21. CNT for tissue regeneration• CNTs are combined with polymers such as poly-l-lactide,Polylactide and poly-D,Llactide- coglycolide copolymer whichhave been used as a scaffolds in tissue regeneration.• It can be prepared by mixing solubilized collagen with solutionhaving carboxylated SWCNTs.• Living smooth muscle cell were integrated at the collagenstage to produce cell-seeded collagen carbon nanotubes.  22. Carbon Nanotubes in Drug Delivery:Recent Trends• f-CNTs have been demonstrated to deliver proteins, nucleic acids, drugs,antibodies and other therapeutics.• Ammonium functionalized CNTs can also be considered very promising vectors forgene-encoding nucleic acids.• CNT’s in Gene Therapy : Gene therapy involves transport of the correct gene byviral or nonviral vectors to the affected area• CNTs seem to represent a very good nonviral vector for gene therapy, because theycan cross the cell membrane by an endocytosis process, and also, because of thefunctionalization of CNTs, the DNA can be transferred without any degradation.• The siRNA delivered via MWCNTs achieved significant inhibition of tumor growth.  23. Commercially available Carbon Nanotubes• Specification details for carbon nanotubes (SWCT & MWCT)available from Aldrich Materials Science, Sigma-Aldrich Co. LLC.Aldrich Product No. TEM Image Description755710 Single-walled isolated and bundled carbonNanotubes powder2 nm x several µm (length, measured byTEM / SEM) Carbon purity : > 70 % (by TGA)Metal oxide impurity: < 30 % (by TGA) Highspecific surface area (> 1000 m2/g )755133Thin multi-walled (avg. 7~9 walls) carbonnanotubes powder 9.5 nm (diameter, byTEM) x 1.5 µm (length, by TEM)Carbon purity : > 95 % (by TGA)Metal oxide impurity: < 5 % (by TGA)High level of purity.  24. Aldrich Product No. TEM Image Description755168 Double-walled isolated andbundled carbon nanotubes powder3.5 nm (diameter, by HRTEM) x 1 -10 µm (length, by TEM / SEM)Carbon purity : > 90 % (by TGA)Metal oxide impurity: < 10 % (byTGA) Specific surfacearea: >500 m2/g (by BET)High filed emission characteristicsTransparency755141 Short double-walled isolated andbundled carbon nanotubes powder3.5 nm (diameter, by HRTEM) x 3µm (length, by TEM / SEM)Carbon purity : > 90 % (by TGA)Metal oxide impurity: < 10 % (byTGA) Surface chemistrycharacteristics.755125 Short thin multi-walled (avg. 7~9walls) carbon nanotubes powder9.5 nm (diameter, by TEM) x < 1 µm(length, by TEM) Carbon purity : >95 % (by TGA) Metal oxideimpurity: < 5 % (by TGA) Surfacechemistry characteristics Ease ofdispersability
  9. 9.  25. Why only Carbon Nanotubes out oftremendous Nanocarriers?• CNTs act as promising drug carrier due to their unique chemical, physical,and biological properties, nanoneedle shape, hollow monolithic structure,and their ability to obtain the desired functional groups on their outerlayers.• In case of gene therapy liposomes and microparticles, seem not to be asafer option because of their poor pharmacokinetic profile of theadministered oligonucleotide and conjugated plasmid DNA.• They can be functionalized to be more water-soluble and serum-stable,with low toxicity at the cellular level.• Detection CNTs does not require any type of fluorescent labelling, such asquantum dots. It can be detected directly by TEM or AFM due to theirelectron emission spectroscopy.• Destruction of cancer cells for thermal ablation.• Another application of CNTs for drug delivery is intravenous injection.  26. Thank You