Aptamers Based Biosensors for Disease Detection

In the fabrication of biosensor, biorecognition elements or bioreceptorplay an important role. Bioreceptor is a biological molecular species (e.g. antibody, enzyme or nucleic acid) or a living biological system (e.g. cells, tissues or whole organisms) that has capability to recognize a target or substrate (analyte) molecules [1]. Bio-recognition elements have unique profile that helps in providing strong affinity for a specific molecule. This specific feature provides biosensor to become highly selective in nature. Different types of bioreceptors such as enzyme, nucleic acid, cell, antibodies, aptamers etc. are being widely used for the fabrication of a biosensor [2-7]. In these bioreceptors, Aptamers shows imminence potential in the fabrication of biosensor. Aptamers are double stranded DNA or single stranded RNA or DNA strands that bind specifically to molecular targets [8]. These “designer” molecules were first developed in 1990 and were followed by the development of systemic evolution of ligands by exponential enrichment (SELEX), which is the technology for isolation of highly specific aptamers. However, a study in 2000’s revealed the presence of “riboswitches”-a type of naturallyoccurring RNA aptamers that function as gene regulators in the cell nucleus. Owing to their small size, high affinity for targets and high pH and temperature stability, aptamers have been under intense investigation for a number of applications, including targeted therapeutics and diagnostics [9].