Fabrication of biomolecule-PEG micropattern on titanium surface and its effects on platelet adhesion

Reducing platelet adhesion, controlling platelet distribution and decreasing degree of platelet activation are very important for improving blood compatibility of cardiovascular implants. In this study, the micropattern of heparin and fibronectin mixture (Hep-Fn) embedded within a cell-resistant α-methoxy-poly(ethylene glycol)-ω-succinimidyl carbonate (mPEG-SC) background was fabricated on titanium (Ti) surface. Firstly, the Ti sample was activated by NaOH solution and treated with ethanol solution of (3-aminopropyl)-triethoxysilane (APTE). Secondly, microtransfer molding (μTM) was used to pattern mPEG-SC for resisting protein absorption and platelet adhesion on silanized Ti surface. Finally, Hep-Fn mixture was absorbed on the areas uncovered by mPEG-SC to form a surface for selective adhesion of platelet. Scanning electron microscopy (SEM) showed the surface morphology of the patterned Ti, Fourier transform infrared spectroscopy (FTIR) demonstrated the existence of Hep-Fn and mPEG-SC on the modified Ti surface. The platelet adhesion test was used to evaluate adhesion, activation and distribution of platelets on the bare Ti samples with or without biomolecule micropattern. The results indicated that the patterned samples could effectively reduce platelet adhesion, control platelet distribution and influence platelet activation compared with the non-patterned pure Ti sample. The micropattern sample, P25/10 with a geometry of 25 μm mPEG-SC (ridges) and 10 μm Hep-Fn (grooves), presented better blood compatibility.