Aptamers are oligonucleotides that can be chemically modified for a variety of down-stream applications. Modifications include fluorescent molecule tags for detection, amino-, carboxy, thiol-, and biotin-modified linkers for coupling to surfaces, and nucleotide analogs and PEGylation for stability. Modified-aptamer chemistry (on the base, sugar, or backbone of the nucleic acid) can also be employed such as hydrophobically-modified aptamers (HMAs) for hydrophobic targets, 2′-F-RNA and other RNA analogs for enhanced stability in vivo. We also consider amino acid-based biopolymers (i.e. peptides) to be aptamers, known as peptimersTM.