Heart valve-inspired self-lubricating anticoagulant surfaces

The poor blood compatibility of medical materials makes them easily cause serious clotting reactions, leading to thrombus and grave complications. To reduce the high risk of postoperative thrombosis, it is urgent to improve the blood compatibility of materials. Inspired by the lubricating layer formed by endothelial secretions in heart valve tissue to maintain the dynamic balance of coagulation system, a self-lubricating anticoagulant surface (SLACS) is proposed. SLACS is obtained by immobilizing silicon-polydimethylsiloxane (S-PDMS) elastomer on porous NiTi substrate through physical adhesion and chemical bonding. The silicone oil stored in the S-PDMS elastomer spontaneously migrates from the inside out to form a lubricating layer, which is caused by the demixing of the silicone oil and polydimethylsiloxane (PDMS) due to the increased free energy of S-PDMS during the curing process. Under the synergistic effect of self-lubricating layer and lyophobic end group of PDMS, the SLACS exhibits excellent blood compatibility. Prepared SLACS not only reduces the blood flow resistance, prevents the activation of coagulation system, suppresses the formation of biofilm and thrombus, but also has excellent resistance to bacterial adhesion and corrosion. In addition, SLACS can maintain long-term stable anti-adhesion under the action of the PDMS lyophobic end group, even if the self-lubricating layer is completely depleted. The simple and safe preparation method of SLACS and its long-term outstanding anticoagulation make it expected to address the complications associated with anticoagulation therapy and inhibit blockage caused by embolism in medical devices, providing a new avenue for the future of intelligent medical treatment.