Aptamers, also known as chemical antibodies, are short single-stranded oligonucleotide molecules that selectively bind to specific targets including proteins, peptides, and carbohydrates. Aptamers recognize and bind targets by a 3-dimensional structure, while antibodies recognize linear epitopes of the targets. Since they are chemically synthesized, the process can simply be scaled-up, there are low batch-to-batch variation and high stability. Besides, the production of the aptamer is fast and cost-effective. Aptamers are highly safe biomaterials with no reported in vivo immunogenicity.