Boronic acid-modified DNA-based aptamers can be selected to recognize fibrinogen through binding at a glycosylation site and thus are useful for probing the effect of glycosylation pattern changes on the ability for fibrinogen to mediate blood coagulation. In addition, the aptamers of the disclosure also have anticoagulation effects due to their binding to fibrinogen and its cleavage product fibrin. The present disclosure, therefore, encompasses methods for inhibiting fibrin coagulation with an aptamer capable of specifically binding to a glycosylation site of fibrinogen or fibrin. The disclosure further provides oligonucleotide aptamers comprising at least one nucleotide having a boronic acid thereon, where the aptamer is capable of selectively binding to a glycosylation site of fibrinogen, or the derivative thereof.