Xu F J, Li Y L, Kang E T, Neoh K G
Department of Chemical and Biomolecular Engineering, National University of Singapore, Kent Ridge, Singapore 119260.
Biomacromolecules. 2005 May-Jun;6(3):1759-68. doi: 10.1021/bm050071w.
Well-defined (nearly monodispersed) poly(poly(ethylene glycol)monomethacrylate)-Si hybrids were prepared via surface-initiated atom transfer radical polymerization (ATRP) of the poly(ethylene glycol)monomethacrylate (PEGMA) macromonomer on the hydrogen-terminated Si(111) surface (Si-H surface). Both the active chloride groups at the chain ends (from the ATRP process) and the chloride groups converted from some ( approximately 32%) of the -OH groups of the Si-C bonded PEGMA polymer, or P(PEGMA), brushes were used as leaving groups for the covalent coupling of heparin. For the heparinized P(PEGMA)-Si hybrid surfaces, protein adsorption and platelet adhesion were significantly suppressed. The well-defined and dense P(PEGMA) brushes, prepared from surface-initiated ATRP, had allowed the immobilization of a relatively high concentration of heparin (about 14 mug/cm(2)). The resulting silicon surface exhibited significantly improved antithrombogenecity with a plasma recalcification time (PRT) of about 150 min. The persistence of high bioactivity for the immobilized heparin on the hybrid surfaces can be attributed to the biocompatibility of the PEGMA units, as well as their role as spacers in providing the immobilized heparin with a higher degree of conformational freedom in a more hydrophilic environment. Thus, the heparin-coupled P(PEGMA)-Si hybrids with anti-fouling and antithrombogenic surfaces are potentially useful in silicon-based implantable devices and tissue engineering.
通过在氢封端的Si(111)表面（Si-H表面）上进行聚（乙二醇）单甲基丙烯酸酯（PEGMA）大分子单体的表面引发原子转移自由基聚合（ATRP），制备了定义明确（近乎单分散）的聚（聚（乙二醇）单甲基丙烯酸酯）-硅杂化物。链端的活性氯基团（来自ATRP过程）以及由Si-C键合的PEGMA聚合物或P(PEGMA)刷的一些（约32%）-OH基团转化而来的氯基团，都被用作肝素共价偶联的离去基团。对于肝素化的P(PEGMA)-硅杂化表面，蛋白质吸附和血小板黏附受到显著抑制。由表面引发的ATRP制备的定义明确且致密的P(PEGMA)刷，能够固定相对高浓度的肝素（约14μg/cm²）。所得的硅表面表现出显著改善的抗血栓形成能力，血浆复钙时间（PRT）约为150分钟。固定在杂化表面上的肝素具有高生物活性，这可归因于PEGMA单元的生物相容性，以及它们作为间隔物在更亲水的环境中为固定的肝素提供更高程度的构象自由度的作用。因此，具有防污和抗血栓形成表面的肝素偶联P(PEGMA)-硅杂化物在基于硅的可植入装置和组织工程中具有潜在的应用价值。
