聚(N-异丙基丙烯酰胺)改性硅表面与血浆蛋白质的相互作用

INTERACTION BETWEEN PNIPAAM MODIFIED SILICON SURFACES AND PLASMA PROTEINS

通过表面引发原子转移自由基聚合(ATRP)在硅表面接枝了聚(N-异丙基丙烯酰胺)(PNIPAAm)聚合物刷,并考察了PNIPAAm改性表面在单一蛋白质溶液以及血浆中与血浆蛋白质之间的相互作用.蛋白质吸附测试表明,与未改性的硅表面相比,改性后的表面对纤维蛋白原的吸附量大大降低,特别是在血浆中纤维蛋白原吸附量小于5 ng/cm2.不同血浆浓度下的蛋白质吸附测试发现PNIPAAm改性后的表面并没有出现明显的"Vroman"效应,说明改性后的表面在与血液接触的初期具有良好的阻抗纤维蛋白原吸附的能力.此外,蛋白质免疫印迹测试进一步发现PNIPAAm改性表面能够排斥绝大多数血浆蛋白质,特别是在凝血过程中起重要作用的几种蛋白质的吸附.实验结果表明,PNIPAAm作为一种常见的温敏性聚合物,同时也具有了良好的排斥纤维蛋白原的非特异性吸附能力和较好的血液相容性.

Poly（N-isopropylacrylamide）（PNIPAAm） ＂brush＂ surfaces were prepared via surface initiated atom transfer radical polymerization（SI-ATRP） on initiator-immobilized silicon surfaces.The interactions between the PNIPAAm modified surfaces and plasma proteins in single protein solutions and in human blood plasma were investigated by radiolabeling and immunoblotting methods.The PNIPAAm modified surfaces showed much lower fibrinogen adsorption than the unmodified silicon.In particular,the adsorption of fibrinogen from plasma at either room temperature or body temperature was less than 5 ng/cm2,suggesting that these surfaces may possess good blood compatibility.In the plasma experiments the Vroman effect（high fibrinogen adsorption at short time or low plasma concentration） was not observed on the PNIPAAm modified surfaces,indicating good fibrinogen resistance in the early stages of blood contact.Moreover,the immunoblot data showed that adsorption from plasma of most of the proteins tested（including the contact coagulation factors：factor XII,factor XI,prekallikrein and high molecular weight kininogen） to the PNIPAAm modified surfaces was also significantly reduced.In general,our results suggest that PNIPAAm,used as a ＂traditional＂ thermo-responsive polymer,is resistant to non-specific protein adsorption and may be a promising candidate for use in blood contact devices.