Aptamers, generated through repetitive selection using SELEX or an equivalent in vivo procedure, are chosen for their ability to bind desired target molecules, which are frequently small molecules useful in therapeutics. In some ways, they may be described as chemically engineered versions of antibodies. Of course, nucleic acid aptamers have advantages over antibodies in that they can be developed rapidly by in vitro methods, taking advantage of the reproducibility of chemical oligonucleotide synthesis and the inherent stability of modified oligonucleotides. A full battery of base, sugar and inter-nucleotide modifications is available for aptamer development.
2’-F-RNA has been used extensively in aptamer development, as well as 2’-F-ANA more recently. An article in The Glen Report by Jeff Carter, Director, Process Chemistry, SomaLogic, Inc. described1 the use of a DNA backbone with 5-substituted dU analogues as slow off-rate modified aptamer (SOMAmer®) reagents to enable multiplexed screening of thousands of serum or plasma proteins. These aptamers also include PC Biotin along with a fluorophore, in this case Cyanine 3, for subsequent detection.
(1) J. Carter, The Glen Report, 2015, 27.1, 6-8.