ABSTRACT
Studies on antibody were documented as early as in 1890. They are proteins found in blood or other body fluid of vertebrates, and are used by the immune system to identify and neutralize antigens (like foreign objects, pathogens like bacteria and virus etc). Antibodies are dominating the biomedical research field especially detection, imaging and inhibition of biological target molecules, and therapeutics so far. However, recently aptamer has been seen to compete with antibodies in all the above areas. Aptamers are single stranded oligonucleotides or peptides that fold into well defined three dimensional shapes, allowing them to bind their targets with high affinity and specificity. Aptamer technology is relatively new and discovered only in 1990. Because of synthetic origin and similar function as antibodies, they are often termed as chemical antibody. Within 25 years of discovery, the first generation of aptamer drug "Macugen" is already marketed and available for public use. The Global market for aptamer was $236 million in 2010 and is expected to be valued at nearly $1.8 billion by 2014, with a growing compound annual growth rate of 67.5%. Various drugs being on the pipeline for clinical trials this emerging field of medical biotechnology is raising significant interest. This article gives an overview how aptamers are similar yet distinctly different from antibodies in terms of synthesis, handling, and applicability.