Patent ID: 8409795

Claim:
A method for identifying a photoaptamer, the method comprising: a) preparing a candidate mixture of nucleic acids, wherein each nucleic acid comprises: i) at least one non-photoreactive placeholding modified pyrimidine; and ii) at least one modified pyrimidine independently selected from the group consisting of the modified pyrimidines having the following structure: b) contacting the candidate mixture with a target, wherein nucleic acids having an increased affinity to the target relative to the candidate mixture may be partitioned from the remainder of the candidate mixture; c) partitioning the increased affinity nucleic acids from the remainder of the candidate mixture; d) amplifying the increased affinity nucleic acids to yield a nucleic acid ligand-enriched mixture of nucleic acids; e) repeating (b)-(d) as desired; f) producing from said nucleic acid ligand-enriched mixture of nucleic acids a candidate photoaptamer or a mixture of candidate photoaptamers by replacing in each nucleic acid of the ligand-enriched mixture of nucleic acids one or more non-photoreactive placeholding pyrimidines with a photoreactive pyrimidine; g) contacting said candidate photoaptamer(s) with said target wherein a candidate photoaptamer-target complex is formed; h) irradiating said candidate photoaptamer-target complex; i) determining whether said candidate photoaptamer-target complex has photocrosslinked; j) repeating (f)-(i) as desired; and k) identifying at least one photoaptamer to the target.