Anticoagulant activity of sulfonated polyrotaxanes as blood-compatible materials

Polyrotaxanes, in which alpha-cyclodextrins (alpha-CDs) are threaded onto poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) triblock copolymers (Pluronic) capped with benzyloxycarbonyl(Z)-L-phenylalanine (Z-L-Phe), were prepared, and sulfopropyl groups were introduced to hydroxyl groups of alpha-CDs in the polyrotaxanes. The supramolecular structure and the chemical composition of the polyrotaxanes after the sulfonation were confirmed by 1H-NMR, 13C-NMR, and elemental analysis. Anticoagulant activity of the polyrotaxanes and sulfonated polyrotaxanes was measured by activated partial thromboplastin time (APTT). It was found that the polyrotaxanes and the sulfonated polyrotaxanes showed greater anticoagulant activity than Pluronic itself, suggesting that both the supramolecular structure of the polyrotaxanes and the sulfonated groups contribute to the inhibition of intrinsic coagulation factors. Finally, our designed polyrotaxanes are suggested to be a promising candidate when fabricating blood-compatible medical devices by blending with or coating on clinically used polymers.