Metal nanoparticles are at the forefront of various areas of research. A nanoparticle is defined as a particle with at least one dimension less than 100 nm. Although metal nanoparticles can be made from many different metals the primary one used is gold.
Gold has the advantage of a biomedical history going back nearly five thousand years; which gives it an aura of safety. Silver, on the other hand, has a bad environmental reputation earned from the known effects of silver on wastewater which was introduced from photographic development. Perhaps the most damning aspect being that there is no way to detect nanosilver once it has been released.
Gold nanoparticles in the shape of spheres, sometimes referred to as nanospheres, have several possible uses in medicine. Due to gold’s natural bio-compatibility gold nanospheres could be used to deliver drugs into cancer tumors, or as an improved, less costly means of detecting some cancers.
Another medical use being explored is the use of gold nanospheres being used to directly destroy malignant melanoma cells. Melanoma is the most dangerous form of skin cancer and kills more than 8,000 people a year. Hollow gold nanospheres can use a special “peptide” to draw the nanosphere to the malignant cells. Once exposed to near-infrared light the nanosphere “cooks” the melanoma while leaving the normal cells untouched.
Gold nanoparticals are being considered for environmental protection both in the production of greener feedstock and water purification. Used as a catalyst the nanoparticles are helpful in preventing the release of extremely toxic forms of mercury into the atmosphere and even in detecting contamination.
Clean energy is a very topical application for nanoparticles and although its importance to the automobile industry can’t be denied the computer industry will be equally interested. Nanoparticles have already proven useful in visual display technology (touch sensitive screens) and are anticipated to improve data storage technology via flash memory devices.
The environment is also served well by metal nanoparticles in the construction of cost and fuel efficient fuel cells. Electrical energy storage has come a long way but is still costly as well as hazardous to the environment. Yi Cui, an engineer at Stanford, is doing revolutionary work that may both lower the expense and the polluting aspects of energy storage. Using nanoparticles to fabricate a special ink, Cui was able to cheaply and efficiently manufacture paper batteries and supercapacitors .
Ordinary paper or fabric after being dipped in the nanoparticle ink could retain their mechanical properties yet be able to store energy. Imagine your house with energy storing wallpapers or recharging your laptop or cell phone by using the stored energy from your T-shirt.
While e-textiles may or may not be the most important uses for metal nanoparticles they do seem to be the most futuristic. "This is the right time to really see what we learn from nanoscience and do practical applications that are extremely promising," said Cui. "The beauty of this is, it combines the lowest cost technology that you can find to the highest tech nanotechnology to produce something great. I think this is a very exciting idea.”
Low cost and high tech are certainly a worthy combination and who could ask for anything more?