Aptamer production

Aptamers are short single-stranded DNA, RNA, or peptide oligomers that bind targets with high affinity and specificity by folding into tertiary structures, much in the way an antibody binds an antigen. Comparable to the binding of both traditional and recombinant antibodies, aptamer binding also occurs through combination of hydrogen bonding, electrostatic interactions, van der Waals forces and stacking interactions. Aptamer-target binding affinities are comparable to and surpass those of traditional mAbs.

Aptamers are isolated from libraries of random-sequence DNA or RNA . The libraries contain nucleic acid sequences that have a central random region flanked on either side by constant regions that enable enzymatic manipulation. The random sequence regions are typically between 20 and 80 nucleotides in length but can be longer depending on the target molecule in use. Random DNA and RNA libraries are prepared by phosphoramidite chemistry on automated DNA synthesizers; it is not necessary for the randomized sequences to endcode functional protein. Creation of nucleic acid libraries can be done in-house or can be outsourced to commercial synthesis companies. The DNA/RNA libraries used for aptamer isolation differ from those generated for rAb isolation [LINK TO rAb PAGE] in that sequences for aptamer production do not have to code for functional proteins.