Nanotechnology for sensing: emerging applications of aptamers based sensors for societal welfare

New developments in nanoscience are leading to a much better understanding and control of the natural sensors and actuators. Using its own version of what scientists call nanoengineering, nature transforms abundant and inanimate ingredients into self-generating and self-repairing entities that move, reproduce and possess intelligence. With recent advances in science and technology scientists can now envision development of materials that possess intelligence and show some of the salient characteristics of living things, especially a structure intricate enough to interact with the chemical environment with selectivity (molecular recognition) and with the ability to transform that chemical environment to suit its needs (actuation). Short- chain single stranded nucleic acids (called aptamers) adopt complex 3-dimensional conformations that can exhibit specific binding abilities and enzymatic activities at ppt level of ligands. The ability of nucleic acids to be chemically synthesized inexpensively and enzymatically amplified makes them molecules of choice for sensing and responding to detrimental entities. For e.g. copper, lead, arsenic detecting aptamers have been isolated and can be planted into sensors for biomedical diagnostics, water remediation, etc. These molecules will benefit from a vehicle for their use in a physiological environment. Nanoparticles are increasingly being studied for this purpose. While utilizing their beneficial functions, possibilities of engulfment of nanoparticles by biological cells and resultant toxicity must also be taken into account. The uncertainty of nanotechnology, especially potential environmental risks of nanoparticles cannot be ignored lest we have another asbestosis to deal with. Recent research shows that depending on their surface chemistry, size, surface area, crystallinity and surface charge, nanoparticles can produce toxicity on cells via different mechanisms and need to be studied in detail.