Emerging Trend In Nanotechnology For Model Era

Dr Monu Verma, Dept. of Chemistry, Uttaranchal University, Dehradun

2017-07-10 12:20:08

Credit:  The Libertarian Republic

Credit: The Libertarian Republic

Nanoscience and technology is a broad and interdisciplinary area of research and development activity that has been growing explosively from late 1990s. Nanotechnology includes the low dimensional materials having may be different structures such as nanoparticles, nanowires, nanorods, nanotubes or nanocrystalline thin films which have much attracted attention in the different field of science and engineering.

Any materials having at least one dimension between about 1 and 100 nm comes into the nano range and it shows the properties that are not found in bulk samples of the same material. These materialsexhibits large surface area,higher electrical resistivity, lower thermal conductivity, greater specific heat and thermal expansion coefficients, and superior soft magnetic properties and due to these properties, these nanomaterials can be used in the different important fields such as in medical,environmental remediation, electrochromic or photochromic devices, gas sensors, solar energy transformation, semiconductors, and solar cells, catalysis and biotech industries, adsorption industries and defence etc.

In medical: One application of nanotechnology in medicine currently being developed involves employing nanoparticles to deliver drugs, heat, light or other substances to specific types of cells (such as cancer cells). Particles are engineered so that they are attracted to diseased cells, which allows direct treatment of those cells. This technique reduces damage to healthy cells in the body and allows for earlier detection of disease.For example, nanoparticles that deliver chemotherapy drugs directly to cancer cells are under development. Tests are in progress for targeted delivery of chemotherapy drugs and their final approval for their use with cancer patients is pending. CytImmuneCompany has published the resultschemotherapy drug system.Nanoparticle attaches to a lymphoma cell and it blocks the cancer cell from attaching to real HLD cholesterol, starving the cancer cell.

Another application of nanoparticles is as a detection of biomolecules. Nanoparticles have been widely used as signal reporters to detect biomolecules in DNA assay, immunoassay and cell bioimaging. Usually, they are derivatized with different functional groups such as nucleic acid-targeted oligonucleotide probes, antibodies and protein to produce nanoprobes. Gold nanoparticle-based probes were used in the identification of pathogenic bacteria in DNA-microarray technology. Scientist have developed nano bubbles which formed around gold nanoparticles. When a nano bubble formed around a solid nanoparticle (such as gold) is heated with a laser then thisnanobubble opens a temporary hole in a cell wall and allows drugs to be injected. The scientific community are planning this method to selectively destroy certain types of cells, and modify others. Currently, researchers have also combined bee venom with nanoparticles to poke holes in the protective envelope around virus particles which kills the virus. This method is being evaluated in lab testing on the HIV virus, however researchers believe the method may be used to fight other viruses.

Nanoparticles are also using as Quantum Dots (crystalline nanoparticles) to identify the location of cancer cells in the body, as a  deliver chemotherapy drugs directly to cancer cells, as a cream that releases nitric oxide gas to fight staph infections. As a micelles to carry and deliver a chemotherapy drug paclitaxel to bladder cancer cells.

In skin product: Nanoparticle also used for the preparation of materials for synthetic skin that may be used in prosthetics. This material is a composite of nickel nanoparticles and a polymer. Silicates nanoparticles can be used to provide a barrier to gasses or moisture in a plastic film used for packaging. This could slow down the process of spoiling or drying out in food.Zinc oxide nanoparticles can be dispersed in industrial coatings to protect wood, plastic, and textiles from exposure to UV rays. Silver nanoparticles in fabric are used to kill bacteria, making clothing odor-resistant. To glow up the skin, nanotechnology is used.

In Energy and ElectronicsResearchers have used nanoparticles called nanotetrapods studded with nanoparticles of carbon to develop low cost electrodes for fuel cells. This electrode may be able to replace the expensive platinum needed for fuel cell catalysts.Combining goldnanoparticles with organic molecules creates a transistor known as a NOMFET (Nanoparticle Organic Memory Field-Effect Transistor). This transistor is unusual in that it can function in a way similar to synapses in the nervous system. Scientist have also used nanoparticles called nanotetrapods studded with nanoparticles of carbon to develop low cost electrodes for fuel cells. This electrode may be able to replace the expensive platinum needed for fuel cell catalysts.

Combining gold nanoparticles with organic molecules creates a transistor known as a NOMFET (Nanoparticle Organic Memory Field-Effect Transistor). This transistor works similar to synapses in the nervous system. A catalyst using platinum-cobalt nanoparticles is being developed for fuel cells that produces twelve times more catalytic activity than pure platinum. In order to achieve this performance, the amorphous nanoparticles were anneal to form crystalline lattice and to reduce the spacing between platinum atoms on the surface and increasing their reactivity. Another example is silicon nanoparticles coated anodes of lithium-ion batteries which can increase battery power and reduce recharge time.Semiconductor nanoparticles are being applied in a low temperature printing process that enables the manufacture of low cost solar cells.

In environment remediation: Currently, groundwater remediation is the most common commercial application of nanoremediationtechnologies. Using nanomaterials, especially zero-valent metals (ZVMs), for groundwater remediation is an emerging approach that is promising due to the availability and effectiveness of many nanomaterials for degrading or sequestering contaminants.

Nanotechnology also offers the potential to effectively treat contaminants in situ, avoidingexcavation or the need to pump contaminated water out of the ground. The process begins with nanoparticles being injected into a contaminated aquifer via an injection well. The nanoparticles are then transported by groundwater flow to the source of contamination. Upon contact, nanoparticles can sequester contaminants (via adsorption or complexation), immobilizing them, or they can degrade the contaminants to less harmful compounds. Contaminant transformations are typically redox reactions. When the nanoparticle is the oxidant or reductant, it is considered as reactive agent.

The ability to inject nanoparticles to the subsurface and transport them to the contaminant source is imperative for successful treatment. Reactive nanoparticles can be injected into a well where they will then be transported down gradient to the contaminated area. Drilling and packing a well is quite expensive. Direct push wells cost less than drilled wells and are the most often used delivery tool for remediation with nanoiron.

In water treatment: The use of various nanomaterials, including carbon nanotubes and TiO2, shows promise for treatment of surface water, including for purification, disinfection, and desalination.Target contaminants in surface waters include heavy metals, organic contaminants, bisphenol and pathogens. For these removal, nanoparticles are using as sorbents, as reactive agents (Photocatalyst or redox agents), or in membranes used for nanofiltration. The nanoparticles possess high reactivity and large surface area due to which these nanoparticles used as effective sorbents to help concentrate target contaminants for solid-phase microextraction, particularly in the form of self-assembled monolayers on mesoporous supports. These nanoparticles also used as effective sorbent for many targets, including heavy metals such as mercury, lead, and cadmium, chromate and arsenate, and radionuclides such as Tc, CS, uranium, and the actinides.

In sensing: Nanoparticles may assist in detecting trace levels of contaminants in field settings, contributing to effective remediation. Instruments that can operate outside of a laboratory often are not sensitive enough to detect trace contaminants. Rapid, portable, and cost-effective measurement systems for trace contaminants in groundwater and other environmental media would thus enhance contaminant detection and cleanup. One potential method is to separate the analytic from the sample and concentrate them to a smaller volume, easing detection and measurement. When small quantities of solid sorbents are used to absorb the target for concentration, this method is referred to as solid-phase micro extraction.

Among the various uses mentioned above, nanotechnology is widely used in different fields from small to high and hope that current century will be known as nanoscience centaury in the science field.