Nature uses ingenious assemblages of atoms in biology to produce bone, nerve, teeth, horn, hide, silk etc. This aspect has inspired scientists to develop synthetic materials of landscape. Lately the viruses, bacteria, algae and fungi are coaxed to produce hitech compounds. Thus the micro-organisms can be used as eco friendly factories for the production of nano products because of their ability to scale up and synthesis strategies for low cost and large scale production being the prime factor. Micro-organisms represent the tremendous untapped potential to produce nano products.
Medical
Medical application potentials are miniaturised analytical devices for medical diagnostics like lab-on-a-chip system. Although biochips or lab-on-a-chip system are microfluidic devices, these are often discussed in the context of nanotechnology.
Molecular diagnostics involves detection of analytical molecules - for example gold nano crystal (the so called quantum dots) are also magnetic nano particles used as markers for the substances like proteins and DNA.
The detection methods is based on several systems such as fluorescence spectroscopy, magnetic field measuring and electron microscopy. The optical colour changes is suitable for self diagnosis for the patients. Molecular diagnostics is the fastest segment of the in vitro diagnostic industry that reached five billions by 2008.
Drug delivery - therapeutics
Controlled and targeted drug delivery systems can be developed provided the nano scale, transportable vehicles are formulated. Transport system can be developed from nano scaleeee cage molecules (liposomes, fullerenes or dendrimers or by couplinano particlesles). The goal is to carry the active drug selectively to the targeted cells by means of nano particles with specific functional sites. Nano particles penetrates the cell membrane and overcome the physiological barriers (blood-brain barrier) in the organism. Nano scale suspension improves the solubility and bioavailability of drugs.
The most prominent application of nanos is tissue and cell specific drug delivery unlike liposomes, dendrimers, metal and semiconductor nanos made of biopolymers such as bacterial spores, viruses that are natural, uniform in size and other precise control for the surface displayed targeting groups and other components.
AntiVEGF antibodies on gold / silver nanos increase the ability of these antibodies to induce apoptosis in chronic lymphocytic leukaemia Bcells.
Nano biotechnology
This technology uses a vast array of microbes or micro-organisms with a vast diversity. The microbes are the workhorses in nature. These organisms have been playing very vital role in the maintenance of ecosystems and environment.
It is only in the last century the utilization of microbes has reached the zenith for the exploitation of their genetic potential that revolutionized genetic engineering technology. Microbes do play a vital role in almost all the activities of human being ranging from food medical and health, energy, environment, biodiversity, metal leaching of toxic and oil wastes, besides contributing to a range of product to replace chemicals that is bioinsectcides, bioviricides and bioweedicides.
Micro-organisms are continuously exposed to stressful situations and their ability to resist these biotic and abiotic stresses is essential for their survival. The ability of microbes to grow in high metal concentrations results from specific mechanisms or resistance. These mechanisms are efflux system, alteration of solubility and toxicity by changes in redox state of metal ion, extracellular complexation or precipitation of metal and the lack of specific metal transport systems. These metal-microbe interactions have an important role in several biotechnological applications including the fields of bioremediation and bioleaching.
The contribution of microbiology to nanotechnology is indeed very important. Metal-microbe interaction studies have led to the synthesis of microbial derived nanocrystallities like cadmium sulphidee lead and gold by the Agarkar Research Institute, Pune. Dr. Pakniker Group have synthesized Cadmium sulphideenano crystallitete of 2 to 2.5 nm size range by an yeast strain of Schiozosaccharomyces Pombe. Similarly, 2-5 nm size range of lead sulphide of 5 to 8 nm size range of Gold and silver crystallites were synthesized.
Medicine and health
Proteins, nucleic acids DNA/RNA, lipids, polysaccharides are all examples of materials that are the building blocks of life due to their inherent nanoscaled size configurations.
Applications are -
- Genetic diagnostic tools and therapy through DNA biochips, intracellular sensors for monitoring cells in the body.
- New formulations for drug route delivery to exactly deliver the drug to the targeted cells that are even inaccessible.
- Novel rejection resistant artificial organs attain higher performance due to their contact surface-to-surface nano structure that is biocompatible with the human body.
Application of nano particles in medicine
Nano particles are used in medicine in several aspects like design, manufacture administration and monitoring of drugs besides being useful in diagnosis and therapy. Nano particles unlike micro or macro sizes exhibit properties viz. strength, electrical conductivity, elasticity and colour.
Some of the numerous benefits of nanomedicins are the detection of cancer by specific markers in the blood using a few 100 molecules of prostate specific antigen (PSA) for the identification of prostate cancer and identification of malignant tumour by cadmium salenide for the location of tumour as well as size. Gold nano particles of 13-20 nm diameter functionalized with a defined number of antibodies that are specific to a particular protein can be detected in blood.
Nano particles can be of assistance in the diagnosis as contrasting agents in ultrasonography, MRI images as well as delivery by virtue of long residence time well as in the treatment due to their penetration inside the cell including the nucleus and access event to even brain, crossing the blood-brain barrier, besides stimulating the natural repair process. Tracking of proteins has become easy by virtue of their intensity of colour where exposed to UV light as compared to fluorescent dyes in vitro as well as in vivo.
We can track a single protein in the living cell. The colour of nano particles depends on particle size 2 nm glow bright green and 5 nm particles appear dark red. Different proteins can be detected. The photo dynamic therapy involves gold coated nano shells (120 nm) that have conjugated antibodies or peptides that make them get attached to cancer cells. When the tumour is irradiated by infra-red laser, gold gets heated there by killing all the cancerous cells. Similarly folic acid is used in the dendrimers for target deliver system.
Nanometer sized particles of pharmaceuticals are used to manufacture drugs like anti emeticss cholesterol lowering drugs, aneroxia, cachexia and during renal transplantation.
In ovarian cancer , a liposome is used to encapsulate the drug to prevent detection and destruction by immune system. Biocompatible and biodegradable scaffolding of nano structured polymer is seeded with cells taken from patient. The cells regenerate fast and the scaffold dissolves slowly. Peptide amphiphiles assist in cell growth and in the treatment of bone injuries.
Silver kills microbes and nano crystalline silver is used as an anti microbial coating on wound dressings and catheters.
Due to the unusual properties of high reactivity due to large mobility due to size may lead to toxicity and studies have to be done on long-term toxicity.