Aptamer

**Semantic type:** Nucleic Acid, Nucleoside, or Nucleotide

**Definition:** Double-stranded DNA or single-stranded RNA oligonucleotide sequences with the capacity to recognize target molecules with high affinity and specificity. Fundamentally distinct from antibodies, aptamers mimic their properties and have emerged as a promising class of molecules in both therapeutic and diagnostic formats. In having small size (8-15 kDa) relative to antibodies (150 kDa), aptamers are candidates for rapid tumor penetration and blood clearance.