title: Highly efficient control of thrombin activity by multivalent nanoparticles.
abstract: We have demonstrated that the incorporation of sulfated galactose acid (sulf-Gal) into thrombin-binding-aptamer (TBA)-conjugated gold nanoparticles (TBA-AuNPs) enables highly effective inhibition of thrombin activity toward fibrinogen. AuNP bioconjugates (TBA(15)/TBA(29)/sulf-Gal-AuNPs) were prepared from 13 nm AuNPs, 15-mer thrombin-binding aptamer (TBA(15)), 29-mer thrombin-binding aptamer (TBA(29)), and sulf-Gal. The numbers of TBA and sulf-Gal molecules per AuNP proved to have a strong impact on inhibitory potency. The best results were observed for 15-TBA(15)/TBA(29)/sulf-Gal-AuNPs (with 15 TBA(15) and 15 TBA(29) molecules per AuNP), which, because of their particularly flexible conformation and multivalency, exhibited ultrahigh binding affinity toward thrombin (K(d)=3.4×10(-12) M) and thus extremely high anticoagulant (inhibitory) potency. Compared to the case without inhibitors (the "normal" value), their measured thrombin clotting time (TCT) was 91 times longer, whereas for TBA(15) alone it was only 7.2 times longer. Their anticoagulant activity was suppressed by TBA-complementary-sequence (cTBA)-modified AuNPs (cTBA(15)/cTBA(29)-AuNPs) at a rate that was 20 times faster than that of free cTBA(15)/cTBA(29). Thus, easily prepared, low-cost, multivalent AuNPs show great potential for biomedical control of blood clotting.
authors.affiliation: Institute of Bioscience and Biotechnology and Center of Excellence for Marine Bioenvironment and Biotechnology, National Taiwan Ocean University, 2, Beining Road, Keelung, 20224, Taiwan.
authors.forename: Chia-Lun
authors.initials: CL
authors.lastname: Hsu
authors.forename: Huan-Tsung
authors.initials: HT
authors.lastname: Chang
authors.forename: Chao-Tsen
authors.initials: CT
authors.lastname: Chen
authors.forename: Shih-Chun
authors.initials: SC
authors.lastname: Wei
authors.forename: Yen-Chun
authors.initials: YC
authors.lastname: Shiang
authors.forename: Chih-Ching
authors.initials: CC
authors.lastname: Huang
mesh_terms: D000143:Acids / Q000737:chemistry; D000925:Anticoagulants / Q000737:chemistry* / Q000494:pharmacology*; D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000494:pharmacology*; D005340:Fibrinogen / Q000378:metabolism*; D005690:Galactose / Q000737:chemistry; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000143:Acids; D000925:Anticoagulants; D052157:Aptamers, Nucleotide; D013457:Sulfur Compounds; C081676:thrombin aptamer; D005340:Fibrinogen; D013917:Thrombin; D005690:Galactose