Patent ID: 8637656

Claim:
An aptamer which binds to IgG and satisfies the requirement (a) or (b): (a) an aptamer no more than 40 nucleotides in length comprising a nucleotide sequence shown by any of SEQ ID NOs:13-18, wherein: (1) uracil may be substituted by thymine, (2) the aptamer is capable of forming a secondary structure represented by following formula: wherein a uracil at a third position in GGUGCU is substituted with a fluorine atom at a 2′ position of ribose; and solid horizontal lines indicate other nucleotides; or (b) an aptamer no more than 40 nucleotides in length comprising a nucleotide sequence shown by any of SEQ ID NOs:13-18, wherein: (1) uracil may be substituted by thymine, (2) the aptamer is capable of forming a secondary structure represented by following formula: wherein a uracil at a third position in GGUGCU is substituted with a fluorine atom at a 2′ position of ribose; and solid horizontal lines indicate other nucleotides, (3) one to four nucleotides other than GGUGCU and AAC are substituted, deleted, inserted or added.