Supramolecular Aptamers on Graphene Oxide for Efficient Inhibition of Thrombin Activity

Ting-Xuan Lin; Pei-Xin Lai; Ju-Yi Mao; Han-Wei Chu; Binesh Unnikrishnan; Anisha Anand; Chih-Ching Huang

doi:10.3389/fchem.2019.00280

Supramolecular Aptamers on Graphene Oxide for Efficient Inhibition of Thrombin Activity

Front Chem. 2019 May 16:7:280. doi: 10.3389/fchem.2019.00280. eCollection 2019.

Authors

Ting-Xuan Lin¹, Pei-Xin Lai¹, Ju-Yi Mao^{1

2

3}, Han-Wei Chu¹, Binesh Unnikrishnan¹, Anisha Anand¹, Chih-Ching Huang^{1

4

5}

Affiliations

¹ Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan.
² Doctoral Degree Program in Marine Biotechnology, National Taiwan Ocean University, Keelung, Taiwan.
³ Doctoral Degree Program in Marine Biotechnology, Academia Sinica, Taipei, Taiwan.
⁴ Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan.
⁵ School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.

Abstract

Graphene oxide (GO), a two-dimensional material with a high aspect ratio and polar functional groups, can physically adsorb single-strand DNA through different types of interactions, such as hydrogen bonding and π-π stacking, making it an attractive nanocarrier for nucleic acids. In this work, we demonstrate a strategy to target exosites I and II of thrombin simultaneously by using programmed hybrid-aptamers for enhanced anticoagulation efficiency and stability. The targeting ligand is denoted as Supra-TBA_15/29 (supramolecular TBA_15/29), containing TBA₁₅ (a 15-base nucleotide, targeting exosite I of thrombin) and TBA₂₉ (a 29-base nucleotide, targeting exosite II of thrombin), and it is designed to allow consecutive hybridization of TBA₁₅ and TBA₂₉ to form a network of TBAs (i.e., supra-TBA_15/29). The programmed hybrid-aptamers (Supra-TBA_15/29) were self-assembled on GO to further boost anticoagulation activity by inhibiting thrombin activity, and thus suppress the thrombin-induced fibrin formation from fibrinogen. The Supra-TBA_15/29-GO composite was formed mainly through multivalent interaction between poly(adenine) from Supra-TBA_15/29 and GO. We controlled the assembly of Supra-TBA_15/29 on GO by regulating the preparation temperature and the concentration ratio of Supra-TBA_15/29 to GO to optimize the distance between TBA₁₅ and TBA₂₉ units, aptamer density, and aptamer orientation on the GO surfaces. The dose-dependent thrombin clotting time (TCT) delay caused by Supra-TBA_15/29-GO was >10 times longer than that of common anticoagulant drugs including heparin, argatroban, hirudin, and warfarin. Supra-TBA_15/29-GO exhibits high biocompatibility, which has been proved by in vitro cytotoxicity and hemolysis assays. In addition, the thromboelastography of whole-blood coagulation and rat-tail bleeding assays indicate the anticoagulation ability of Supra-TBA_15/29-GO is superior to the most widely used anticoagulant (heparin). Our highly biocompatible Supra-TBA_15/29-GO with strong multivalent interaction with thrombin [dissociation constant (K _d) = 1.9 × 10^-11 M] shows great potential as an effective direct thrombin inhibitor for the treatment of hemostatic disorders.

Keywords: anticoagulation; aptamer; graphene oxide; self-assembly; thrombin.