Potential applications of Nanoparticles

International Journal of Pharma and Bio Sciences

V1(1)2010

Potential applications of Nanoparticles Abhilash M Department of Biotechnology,The Oxford college of Engineering,Bangalore,INDIA.

Corresponding Author [email protected]

ABSTRACT Nanoparticles (NP) are defined as particles with a diameter smaller than 100 nm, are increasingly used in different applications, including drug carrier systems and to pass organ barriers such as the blood-brain barrier. Because of their unique properties Nanocrystals (quantum dots) and other nanoparticles (gold colloids, nanobars, dendrimers and nanoshells) have been receiving a lot of attention for potential use in Therapeutics, Bioengineering and therapeutics drug discovery. In this review potential use of these Nanocrystals and Nanoparticles in various important areas has been discussed. Special properties of these nanoparticles may offer new advancement in drug discovery.

KEYWORDS Nanoparticles , types, applications.

INTRODUCTION

size-related properties that differ significantly from those observed in fine particles or bulk materials [1][2] . Although the size of most molecules would fit into the above outline, individual molecules are usually not referred to as nanoparticles. Nanoclusters have at least one dimension between 1 and 10 nanometers and a narrow size distribution. Nanopowders[3] are agglomerates of ultrafine particles, nanoparticles, or nanoclusters. Nanometer-sized single crystals, or single-domain ultrafine particles, are often referred to as nanocrystals. Nanoparticle research is currently an

In nanotechnology, a particle is defined as a small object that behaves as a whole unit in terms of its transport and properties. It is further classified according to size: in terms of diameter, fine particles cover a range between 100 and 2500 nanometers, while ultrafine particles, on the other hand, are sized between 1 and 100 nanometers. Similar to ultrafine particles, nanoparticles are sized between 1 and 100 nanometers. Nanoparticles may or may not exhibit 1 www.ijpbs.net

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Potential applications of Nanoparticles area of intense scientific interest due to a wide variety of potential applications in biomedical, optical and electronic fields. The National Nanotechnology Initiative has led to generous public funding for nanoparticle research in the United States.

that of other particles and materials, allowing for catalytic promotion of reactions, as well as their ability to adsorb and carry other compounds. The reactivity of the surface originates from quantum phenomena and can make NP unpredictable since, immediately after generation, NP may have their surface modified, depending on the presence of reactants and adsorbing compounds, which may instantaneously change with changing compounds and thermodynamic conditions. Therefore, on one hand, NP have a large (functional) surface which is able to bind, adsorb and carry other compounds such as drugs, probes and proteins. On the other hand, NP has a surface that might be chemically more reactive compared to their fine analogues (6).

Nanoparticles play an important role in a number of these applications. “NPs,” which in general terms are defined as engineered structures with diameters of < 100 nm, are devices and systems produced by chemical and/or physical processes having specific properties(5). The reason why nanoparticles (NP) are attractive for such purposes is based on their important and unique features, such as their surface to mass ratio, which is much larger than

TYPES OF NANOPARTICLES

Figure 1: Types of nanoparticles 2 www.ijpbs.net

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Potential applications of Nanoparticles LIPOSOMES

and no carrier is needed, eliminating potential toxicity issues associated with the carrier molecule. Nanocrystal technology can be utilized for many dosage forms. Nanoparticles offer the potential for targeting the mucosa of the gastrointestinal tract after oral administration, and targeting the cells of the mononuclear phagocytic system (MPS) to treat infections of the MPS such as fungal mycobacterial infections and leishmaniasis, thus serving as a favourable delivery system for drugs like amphotericin B, tacrolimus, etc. The size of nanocrystals allows for safe and effective passage through capillaries. Potential of nanocrystals can be inferred by the FDA approval of Rapamune®, containing sirolimus which is an immunosuppressant drug to prevent graft rejection in children after liver transplantation and Emend®, which contains aprepitant, MK 869, is used in the treatment of emesis associated with the cancer chemotherapy.

Liposomes are concentric bilayered vesicles in which an aqueous volume is entirely enclosed by a membranous lipid bilayer mainly composed of natural or synthetic phospholipids. Liposomes are characterized in terms of size, surface charge and number of bilayers. It exhibits number of advantages in terms of amphiphilic character, biocompatibility, and ease of surface modification rendering it a suitable candidate delivery system for biotech drugs. Liposomes have been used successfully in the field of biology, biochemistry and medicine since its origin. These alter the pharmacokinetic profile of loaded drug to a great extent especially in case of proteins and peptides and can be easily modified by surface attachment of polyethylene glycol-units (PEG) making it as stealth liposomes and thus increase its circulation half-life (8) . NANOCRYSTALS

SOLID LIPID NANOPARTICLES

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Solid lipid nanoparticles (SLN) were developed at the beginning of the 1990s as an alternative carrier system to emulsions, liposomes and polymeric nanoparticles as a colloidal carrier system for controlled drug delivery. Main reason for their development is the combination of advantages from different carriers systems like liposomes and polmeric nanoparticles. SLN have been developed and investigated for parenteral , pulmonal and dermal application routes. Solid Lipid Nanoparticles consist of a solid lipid matrix, where the drug is normally incorporated, with an average diameter below 1 µm. To avoid aggregation and to stabilize the dispersion, different surfactants are used that have an accepted GRAS (Generally Recognized as Safe) status. Nanoparticles are also produced by high pressure homogenisation as

NANOSUSPENSION Nanocrystals are aggregates of around hundreds or thousands of molecules that combine in a crystalline form, composed of pure drug with only a thin coating comprised of surfactant or combination of surfactants. Problems typical of poorly soluble drugs like reduced bioavailability, improper absorption pattern and problems of preparing the parenteral dosage form may be resolved by formulation as nanocrystals. This has several benefits, unlike carrier-based nanoparticles in which extent of loading may be low. Only a minimum quantity of surfactants needs to be added in nanocrystals for steric and electrostatic surface stabilization. Moreover, administration of high drug levels with depot release can be achieved if dissolution is sufficiently slow.. As pure drug is used 3 www.ijpbs.net

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Potential applications of Nanoparticles described for nanosuspensions . SLN have been considered as new transfection agents using cationic lipids for the matrix lipid composition. Cationic solid lipid nanoparticles (SLN) for gene transfer can be formulated using the same cationic lipids as for liposomal transfection agents. In comparison to DOTAPliposomes tested cationic nanoparticles liposomes showed the same transfection rate and gene expression as liposomes. Cationic lipid composition seems to be more dominant for in vitro transfection performance than the kind of colloidal structure it is arranged in. Hence, cationic SLN extend the range of highly potent non-viral transfection agents by one with favourable and distinct technological properties.

polymeric nanoparticles may have engineered specificity, allowing them to deliver a higher concentration of pharmaceutical agent to a desired location. Mostly under the term of nanoparticle, nanospheres are understood. From its definition nanospheres are considered as a matrix system in which the matrix in uniformly dispersed. It should be mentioned, that besides of these spheric vesicular systems nanocapsules are also known, where a polymeric membrane surrounds the drug in a matrix core. The choice of polymer and the ability to modify drug release from polymeric nanoparticles have made them ideal candidates for cancer therapy, delivery of vaccines, contraceptives and delivery of targeted antibiotics. Moreover, polymeric nanoparticles can be easily incorporated into other activities related to drug delivery, such as tissue engineering, and into drug delivery for species other than humans. From the polymer chemistry viewpoint, there will be in the future a challenging field to create new polymers matching hydrophilic and lipophilic properties of upcoming drugs for smart formulation (4).

POLYMERIC NANOPARTICLES In comparison to SLN or nanosuspensions polymeric nanoparticles (PNPs) consists of a biodegradable polymer. Biocompatibility is an essential feature for potential application as tissue engineering, drug and gene delivery and new vaccination strategies. Most biodegradable polymers consists of synthetic polyesters like polycyanoacrylate or poly(D, L-lactide) and related polymers like poly(lactid acid) PLA or poly(lactide-co-glycolide) to give a few examples. Latest developments also include natural polymers like chitosan, gelatin, and sodium alginate to overcome some toxicological problems with the synthetic polymers. Polymeric nanoparticles represent a significant improvement over traditional oral and intravenous methods of administration in terms of efficiency and effectiveness. The advantages of using PNPs in drug delivery are many, being the most important that they generally increase the stability of any volatile pharmaceutical agents and that they are easily and cheaply fabricated in large quantities by a multitude of methods. Also,

DENDRIMERS Dendrimers, a unique class of polymers, are highly branched macromolecules whose size and shape can be precisely controlled. Dendrimers are fabricated from monomers using either convergent or divergent stepgrowth polymerization. Two representations of polyamidoaminebased dendrimers. The welldefined structure, monodispersity of size, surface functionalization capability, and stability are properties of dendrimers that make them attractive drug carrier candidates. Drug molecules can be incorporated into dendrimers via either complexation or encapsulation. Dendrimers are being investigated for both drug and gene delivery, as carriers for penicillin, and for use in 4

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Potential applications of Nanoparticles anticancer therapy. Dendrimers used in drug delivery studies typically incorporate one or more of the following polymers: polyamidoamine (PAMAM), melamine, poly(L-glutamic acid) (PG) , polyethyleneimine (PEI) , poly(propyleneimine), and poly(ethylene glycol) (PEG) ,Chitin.

antibody delivery , and porous silica nanoparticles containing antibiotics , enzymes , and DNA . CARBON STRUCTURES Two nanostructures,that have received much attention in recent years are hollow, carbon-based, cage-like architectures: nanotubes and fullerenes, also known as buckyballs. Single-wall nanotubes (SWNTs), multiwall nanotubes (MWNTs), and C60 fullerenes are common configurations. The size, geometry, and surface characteristics of these structures make them appealing for drug carrier usage. SWNTs and C60 fullerenes have diameters on the order of 1nm, about half the diameter of the average DNA helix. MWNTs have diameters ranging from several nanometers to tens of nanometers depending on the number of walls in the structure. Fullerenes and carbon nanotubes are typically fabricated using electric arc discharge (EAD), laser ablation (LA), chemical vapor deposition (CVD), or combustion processes. Surface-functionalized carbon nanotubes (CNTs) can be internalized within mammalian cells, and when linked to peptides may be used as vaccine delivery structures. With use of molecular dynamics (MD) simulations, the flow of water molecules through CNTs has been modeled and implies their potential use as small molecule transporters. Other simulations have involved the transport of DNA through CNTs, indicating potential use as a gene delivery tool. For example, temperature-stabilized hydrogels for drug delivery applications incorporate CNTs. Fullerenes have also shown drug targeting capability. Tissue-selective targeting and intracellular targeting of mitochondria have been shown with use of fullerene structures. Furthermore, experiments with fullerenes have also shown that they exhibit antioxidant and antimicrobial behavior.

SILICON-BASED STRUCTURES Silicon-based structures can be fabricated by photolithography, etching, and deposition techniques commonly used in the manufacture of semiconductors and microelectromechanical systems (MEMS). The most commonly investigated silicon-based materials for drug delivery are porous silicon and silica, or silicon dioxide. Architectures include calcified nanopores, platinum-containing nanopores, porous nanoparticles, and nanoneedles. The density and diameter of the nanopores can be accurately controlled to achieve a constant drug delivery rate through the pores. Porous hollow silica nanoparticles (PHSNP) are fabricated in a suspension containing sacrificial nanoscale templates such as calcium carbonate. Silica precursors, such as sodium silicate, are added into the suspension, which is then dried and calcinated creating a core of the template material coated with a porous silica shell. The template material is then dissolved in a wet etch bath, leaving behind the porous silica shell. Creation of drug carriers involves the mixing of the PHSNPs with the drug molecule and subsequently drying the mixture to coalesce the drug molecules to the surface of the silica nanoparticles. As shown, the porous hollow nanoparticles exhibit a much more desirable gradual release. Examples of therapies being investigated for use with silicon-based delivery systems include porous silicon embedded with platinum as an antitumor agent , calcified porous silicon designed as an artificial growth factor , silicon nanopores for 5 www.ijpbs.net

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Potential applications of Nanoparticles Targeting is the ability to direct the drug-loaded system to the site of interest. Two major mechanisms can be distinguished for addressing the desired sites for drug release: (i) passive and (ii) active targeting. An example of passive targeting is the preferential accumulation of chemotherapeutic agents in solid tumors as a result of the enhanced vascular permeability of tumor tissues compared with healthy tissue. A strategy that could allow active targeting involves the surface functionalization of drug carriers with ligands that are selectively recognized by receptors on the surface of the cells of interest. Since ligand–receptor interactions can be highly selective, this could allow a more precise targeting of the site of interest (10). Passive targeting with nanoparticles, however, encounters multiple obstacles on the way to their target; these include mucosal barriers, nonspecific uptake of the particle and non-specific delivery of the drug (as a result of uncontrolled release). Therefore, two most important aspects of nanoparticle drug delivery must be: • The specific targeting of the diseased tissue with nanoparticles (appropriate size and functionalization with antibodies—or other means of selective binding—provides means of enhanced delivery of drugs and reduced nonspecific toxicity); and • The timed release of the drug (to prevent nonspecific toxicity the drug must not diffuse out of the particle while it is still in the circulatory system, and must remain encapsulated until the particle binds to the target). One way to overcome the first issue is to functionalize the nanoparticles with recognition elements on their surfaces towards receptors present on the particular diseased tissue.The conjugated antibodies or short chain variable fragments (scFvs) will provide selective binding to the specific cell’s

METAL STRUCTURES Hollow metal nanoshells are being investigated for drug delivery applications. Typical fabrication methods involve templating of the thin metal shell around a core material such as a silica nanoparticle. Typical metals include gold, silver, platinum, and palladium. When linked to or embedded within polymeric drug carriers, metal nanoparticles can be used as thermal release triggers when irradiated with infrared light or excited by an alternating magnetic field. Biomolecular conjugation methods of metals include bifunctional linkages, lipophilic interaction, silanization, electrostatic attraction, and nanobead interactions (9) .

APPLICATIONS OF NANOPARTICLES Targeted Drug delivery A key area in drug delivery is the accurately targeting of the drug to cells or tissue of choice. Drug targeting systems should be able to control the fate of a drug entering the body. Today’s delivery technologies are far away from the design of the so called “magic bullet”, proposed by Paul Ehrlich at the beginning of the 20th century, in which the drug is precisely targeted to the exact side of action. Nanotechnology offers here another challenge to come to this goal a bit closer, to deliver the drug in the right place at the right time (4). Nanotechnology is expected to bring a fundamental change in manufacturing in the next few years and will have an enormous impact on Life Sciences, including drug delivery, diagnostics, nutriceuticals and the production of biomaterials. 6 www.ijpbs.net

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Potential applications of Nanoparticles surface, and their endocytosis will be enhanced with suitably adjusted binding affinities. To address the second issue, multilayered nanoparticles can be engineered, where each layer will contain one drug from the cocktail, and their release will be sequenced in accordance with the appropriate timing of the delivery of each drug for combination therapy. Currently a significant amount of research shows that combination therapy is more effective than traditional therapies (11). Nanoparticles can be used in targeted drug delivery at the site of disease to improve the uptake of poorly soluble drugs the targeting of drugs to a specific site, and drug bioavailability. A schematic comparison of untargeted and targeted drug delivery systems is shown below. Several anti-cancer drugs including paclitaxel ,doxorubicin 5-fluorouracil and dexamethasone have been successfully formulated using nanomaterials. Polylactic/glycolic acid (PLGA) and polylactic acid (PLA) based nanoparticles have been formulatedto encapsulate dexamethasone, a glucocorticoid with an intracellular site of action. Dexamethasone is a chemotherapeutic agent that has anti-proliferative and anti-inflammatory effects. The drug binds to the cytoplasmic receptors and the subsequent drug-receptor complex is transported to the nucleus resulting in the expression of certain genes that control cell proliferation (12) Site-specific-targeted drug delivery is important in the therapeutic modulation of effective drug dose and disease control. Targeted encapsulated drug delivery using NPs is more effective for improved bioavailability, minimal side effects, decreased toxicity to other organs, and is less costly. NP-based drug delivery is feasible in hydrophobic and hydrophilic states through variable routes of administration, including oral, vascular, and inhalation. In drug delivery, several approaches are

currently being tested for better site-specific delivery of an effective dose using liposomes, polymeric micelles, dendrimeres, ceramic NPs, iron oxide, proteins, covalent binding, adsorption,conjugation, and encapsulation methods (13). ADVANTAGES OF USING NANOPARTICLES IN DRUG DISCOVERY: •

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Particle size and surface characteristics of nanoparticles can be easily manipulated to achieve both passive and active drug targeting after parenteral administration. They control and sustain release of the drug during the transportation and at the site of localization, altering organ distribution of the drug and subsequent clearance of the drug so as to achieve increase in drug therapeutic efficacy and reduction in side effects. Site-specific targeting can be achieved by attaching targeting ligands to surface of particles or use of magnetic guidance. The system can be used for various routes of administration including oral, nasal, parenteral, intra-ocular etc (7). Nanoparticles can better deliver drugs to tiny areas within the body. Engineering on this scale enables researchers to exercise exquisite and previously unthinkable control over the physical attributes of polymers and other biomaterials. Nanoparticles overcome the resistance offered by the physiological barriers in the body because efficient delivery of drug to various parts of the body is directly affected by particle size. Nanoparticles aid in efficient drug delivery to improve aqueous solubility of poorly soluble

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Potential applications of Nanoparticles

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drugs that enhance Bioavailability for timed release of drug molecules, and precise drug targeting. The surface properties of nanoparticles can be modified for targeted drug delivery for e.g. small molecules, proteins, peptides, and nucleic acids loaded nanoparticles are not recognized by immune system and efficiently targeted to particular tissue types. Targeted nano drug carriers reduce drug toxicity and provide more efficient drug distribution. Nanocarriers holds promise to deliver biotech drugs over various anatomic extremities of body such as blood brain barrier (8).

When mixed together in a sample containing CEA, the biomarker bound both types at once, forming a dimer and decreasing the total number of nanoparticles in the sample. The change was detected by measuring the decrease in the number of photon bursts from the gold nanoparticles when they passed under a focused laser beam - the more CEA was present, the greater the decrease.A similar experimental set-up has been used for over a decade for single-molecule fluorescence detection, notes Shuming Nie, who studies cancer nanotechnology at Emory University in the US. But an exciting finding is that bioconjugated colloidal gold nanoparticles can be counted with such a set-up, with signals that are dramatically more intense than organic dyes or quantum dots.

Gold nanoparticles detect cancer

Nanoparticles target ovarian cancer

Chinese scientists have used gold nanoparticles as ultrasensitive fluorescent probes to detect cancer biomarkers in human blood. The approach is so sensitive, according to researchers, that it outstrips current methods by several orders of magnitude and could also be employed in direct detection of viral or bacterial DNA. Gold nanoparticles are promising probes for biomedical applications because they can be easily prepared and, unlike other fluorescent probes such as quantum dots or organic dyes, don't burn out after long exposure to light.In the new study, Jicun Ren and colleagues at Shanghai Jiaotong University in China apply the particles to detect carcinoembryonic antigen (CEA) and alpha foetal protein (AFP) - two important biomarkers in the diagnosis of various cancers, including liver, lung and breast cancer.To measure biomarker levels, the researchers conjugated their gold nanoparticles to antibodies. For CEA, for example, they made two different types of nanoparticles, each one bearing a different antibody.

Tiny particles carrying a killer gene can effectively suppress ovarian tumor growth in mice, according to a team of researchers from MIT and the Lankenau Institute.The findings could lead to a new treatment for ovarian cancer, which now causes more than 15,000 deaths each year in the United States. Because it is usually diagnosed at a relatively late stage, ovarian cancer is one of the most deadly forms of the disease.The new treatment, reported in the Aug. 1 issue of the journal Cancer Research, delivers a gene that produces the diphtheria toxin, which kills cells by disrupting their ability to manufacture proteins. The toxin is normally produced by the bacterium Corynebacterium diphtheriae.Human clinical trials could start, after some additional preclinical studies, in about a year or two, says Daniel Anderson, research associate in the David H. Koch Institute for Integrative Cancer Research at MIT and a senior author of the paper.Currently ovarian cancer 8

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Potential applications of Nanoparticles patients undergo surgery followed by chemotherapy. In many cases, the cancer returns after treatment, and there are no good therapies for recurring and advanced-stage tumors.Anderson and others from MIT, including Institute Professor Robert Langer, along with researchers from the Lankenau Institute, led by Professor Janet Sawicki, found that the genetherapy treatment was equally as effective, and in some cases more effective, than the traditional chemotherapy combination of cisplatin and paclitaxel. Furthermore, it did not have the toxic side effects of chemotherapy because the gene is engineered to be overexpressed in ovarian cells but is inactive in other cell types.

Stem cell therapy Nanoparticles may prove effective tools for improving stem cell therapy, new research suggests. Chemical engineers have successfully used nanoparticles to enhance stem cells' ability to stimulate regeneration of damaged vascular tissue and reduce muscle degeneration in mice, they report in a study published online on October 5 in Proceedings of the National Academy of Sciences. Researchers studying the role of stem cells in stimulating new blood vessel formation have suggested that after implantation into a living organism, cells may not continue to renew tissue effectively enough to keep the tissue alive long-term. The cells can therefore benefit from help with performance-enhancing genes, which promote growth in the target tissue. Researchers generally rely on viral vectors to deliver these therapeutic genes to stem cells.

To further ensure tumor-focused effects, the nanoparticles were administered by injection into the peritoneal cavity, which encases abdominal organs such as the stomach, liver, spleen, ovaries and uterus. Ovarian cancer is known to initially spread throughout the peritoneal cavity, and current therapeutic approaches in humans include direct injection into the peritoneal space, thereby targeting the therapy to the ovaries and nearby tissues where tumors may have spread.The new nanoparticles are made with positively charged, biodegradable polymers known as poly(beta-amino esters). When mixed together, these polymers can spontaneously assemble with DNA to form nanoparticles. The polymer-DNA nanoparticle can deliver functional DNA when injected into or near the targeted tissue. For several years, the MIT-Lankenau team has been developing these nanoparticles as an alternative to viruses, which are associated with safety risks. In addition to ovarian cancer, these nanoparticles have demonstrated potential for treatment of a variety of diseases, including prostate cancer and viral infection.

Chemistry researchers at the University of Warwick have found that tiny nanoparticles could be twice as likely to stick to the interface of two non mixing liquids than previously believed. This opens up a range of new possibilities for the uses of nanoparticles in living cells, polymer composites, and high-tech foams, gels, and paints. The researchers are also working on ways of further artificially enhancing this new found sticking power.In a paper entitled "Interaction of nanoparticles with ideal liquid-liquid interfaces" published in Physical Review Letters the University of Warwick researchers reviewed molecular simulations of the interaction between a non-charged nanoparticle and an "ideal" liquid-liquid interface. They were surprised 9

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Potential applications of Nanoparticles to find that very small nanoparticles (of around 1 to 2 nanometres) varied considerably in their simulated ability to stick to such interfaces from what was expected in the standard model.The researchers found that it took up to 50 percent more energy to dislodge the particles from the liquid-liquid interface for the smallest particle sizes. However as the radius of the particles increased this deviation from the standard model gradually faded out.The researchers, Dr ir Stefan A. F. Bon and Dr David L. Cheung, believe that previous models failed to take into account the action of "capillary waves" in their depiction of the nanoparticles behaviour at the liquid to liquid interfaces.

flavor and nutritional values much longer. Silver is naturally anti-germ, anti-mold and anti-fungus. In tests comparing FresherLonger to conventional containers, the 24-hour growth of bacteria inside Fresher Longer containers was reduced by over 98 percent because of the silver nanoparticles, the company claimed. To further preserve flavor and nutrients - and to delay and reduce spoiling - the FresherLonger containers have an airtight siliconegasket locking system. The containers are made of airand odor-impermeable polypropylene. The silver nanoparticles average about 25nm (nanometers) in diameter, or about 200 thousandth of a human hair. Their natural color gives FresherLonger Miracle Food Storage containers a distinctive golden hue. A variety of other companies are also pioneering developments in food packaging, including techniques to improve food safety and supply chain tracking. Some nanotech products, such as anti-microbial films, have already entered the market.

Container uses nanoparticles to extend shelf life A plastic container that uses silver nanoparticles to keep foods fresher longer, points the way forward for processors looking to incorporate the technology into their packaging. The technology is attractive to the food industry as it promises to yield new solutions to key challenges. Research and development underway includes the development of functional food, nutrient delivery systems and methods for optimizing food appearance, such as colour, flavour and consistency.In the food-packaging arena, nanomaterials are being developed with enhanced mechanical and thermal properties to ensure better protection of foods from exterior mechanical, thermal, chemical or microbiological effects. The new containers, being marketed to consumers by Sharper Image (a specialty retailer in the US) are infused with naturally antibacterial silver nanoparticles. This keeps foods fresher three or even four times longer than normal, Sharper Image claims. The containers can be used to store fruits, vegetables, herbs, breads, cheeses, soups, sauces and meats while maintaining color,

Anthrax Vaccine Uses Nanoparticles To Produce Immunity A vaccine against anthrax that is more effective and easier to administer than the present vaccine has proved highly effective in tests in mice and guinea pigs, report University of Michigan Medical School scientists in the August issue of Infection and Immunity.The scientists were able to trigger a strong immune response by treating the inside of the animals' noses with a "nanoemulsion" a suspension of water, soybean oil, alcohol and surfactant emulsified to create droplets of only 200 to 300 nanometers in size. It would take about 265 of the droplets lined up side by side to equal the width of a human hair.The oil particles are small enough to ferry a key anthrax protein inside the nasal membranes, 10

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Potential applications of Nanoparticles allowing immune-system cells to react to the protein and initiate a protective immune response. That primes the immune system to promptly fight off infection when it encounters the whole microbe.Besides eliminating the need for needles, the nanoemulsion anthrax vaccine has another advantage, the researchers say: It is easy to store and use in places where refrigeration is not available.An effective and easy-to-administer vaccine would be a valuable tool for health authorities dealing with any future attack in which a terrorist might spread anthrax microbes. The researchers say a nasal nanoemulsionbased anthrax vaccine, if it proves effective in humans, could be given easily to people even after they are exposed in an anthrax attack, along with antibiotics. With some diseases, vaccines given after exposure are used to boost the speed of the immune response.

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ASTM E 2456 - 06 Standard Terminology Relating to Nanotechnology 3. Fahlman, B. D. Materials Chemistry; Springer: Mount Pleasant, MI, 2007; Vol. 1, pp 282–283. 4. O.Kayser, A. Lemke and N. Hernández-Trejo. (2005) The Impact of Nanobiotechnology on the development of new drug delivery systems. Current Pharmaceutical Biotechnology. 6(1):3-5. 5. Maureen R. Gwinn and Val Vallyathan. (2006) Nanoparticles: Health Effects—Pros and Cons Environmental Health Perspectives. 114(12):1818- 1825. 6. Paul J. A. Borm and Wolfgang Kreyling. (2004) Toxicological Hazards of Inhaled NanoparticlesPotential Implications for Drug Delivery. Journal of Nanoscience and Nanotechnology. 4(6):1-11. 7. Mohsen Jahanshahi and Zahra Babaei. (2008) Protein nanoparticle: A unique system as drug delivery vehicles. African Journal of Biotechnology. 7 (25):4926-4934. 8. Manju Rawat, Deependra Singh, S. Saraf, and Swarnlata Saraf. (2006) Nanocarriers: Promising Vehicle for Bioactive Drugs. Biol. Pharm. Bull. 29(9):1790—1798. 9. Gareth A. Hughes. (2005) Nanostructuremediated drug delivery. Nanomedicine: Nanotechnology, Biology, and Medicine. 1:22– 30. 10. Costas Kaparissides, Sofia Alexandridou, Katerina Kotti and Sotira Chaitidou. (2006) Recent advances in novel drug delivery systems. 11. Z.B. Bilgiçer, H.-C. Chang, C. D’Souza-Schorey, B. Smith, and E. Y. Zhu (2007) Targeted Nanoparticle Drug Delivery. 12. Sarabjeet Singh Suri, Hicham Fenniri and Baljit Singh. (2007) Nanotechnology-based drug delivery systems. Journal of Occupational Medicine and Toxicology. 2:16.

Conclusion Nanoparticles have been used extensively for applications in drug discovery, drug delivery delivery, diagnostics and for many others in medical field. Nanoparticles can also contribute to stronger, lighter, cleaner and “smarter” surfaces and systems. They are already being used in the manufacture of scratchproof eyeglasses, crack-resistant paints, anti-graffiti coatings for walls, transparent sunscreens, stainrepellent fabrics, self-cleaning windows and ceramic coatings for solar cells.

References 1.

Cristina Buzea, Ivan Pacheco, and Kevin Robbie (2007). "Nanomaterials and Nanoparticles: Sources and Toxicity". Biointerphases 2: MR17– MR71. 11

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Potential applications of Nanoparticles 13. Maureen R. Gwinn and Val Vallyathan. (2006) Nanoparticles: Health Effects—Pros and Cons Environmental Health Perspectives. 114(12):1818- 1825.

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