Time-of-Flight-Secondary Ion Mass Spectrometry Study of the Temperature Dependence of Protein Adsorption onto Poly(N-isopropylacrylamide) Graft Coatings
Time-of-Flight-Secondary Ion Mass Spectrometry Study of the Temperature Dependence of Protein Adsorption onto Poly(N-isopropylacrylamide) Graft Coatings
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DOI：
10.1021/ac9009337
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发表时间：
2009-08-15
影响因子：
7.4
通讯作者：
Griesser, Hans J.
中科院分区：
文献类型：
--
作者：
Cole, Martin A.;Jasieniak, Marek;Griesser, Hans J.
刺激响应材料显示出相当大的应用前景，需要控制在固体材料界面的生物分子相互作用。接枝涂层的聚（N-异丙基丙烯酰胺）（pNIPAM）是感兴趣的生物医学和生物技术的应用，由于其温度依赖性的切换之间的粘附和非粘附状态的细胞和蛋白质的表面性质。蛋白质吸附到这些可切换涂层的表征是一项艰巨的任务，因为切换不仅影响对蛋白质的亲和力，而且同时引起涂层的显著变化。在这里，高灵敏度的分析技术飞行时间-二次离子质谱（TOF-SIMS）结合主成分分析（PCA）用于表征蛋白质吸附到pNIPAM涂层上的特征，所述涂层通过自由基聚合到表面结合的可聚合基团上制备。研究了在高于和低于聚合物的低临界溶解温度（LCST）的温度下，从磷酸盐缓冲溶液中吸附牛血清白蛋白和溶菌酶到pNIPAM涂层上的情况。低于LCST，即使用这种超灵敏的方法也不能检测到吸附的蛋白质。而在LCST以上，检测到吸附蛋白的量对应于小于单层。PCA负荷图显示，未观察到可能导致蛋白质暴露后混淆或误导光谱变化的外源污染物。
Stimuli-responsive materials show considerable promise for applications that require control over biomolecule interactions at solid material interfaces. Graft coatings of poly(N-isopropylacrylamide) (pNIPAM) are of interest for biomedical and biotechnological applications due to their temperature-dependent switching of surface properties between adhesive and nonadhesive states for cells and proteins. The characterization of protein adsorption to these switchable coatings is a formidable task since switching not only influences the affinity for proteins but at the same time induces a significant change in the coating. Here, the highly sensitive analytical technique of time-of-flight-secondary ion mass spectrometry TOF-SIMS) combined with principal component analysis (PCA) was used for the characterization of protein adsorption onto pNIPAM coatings prepared by free radical polymerization onto surface-bound polymerizable groups. Adsorption of bovine serum albumin and lysozyme onto pNIPAM coatings from phosphate buffered solutions was investigated at temperatures above and below the polymer's lower critical solution temperature (LCST). Below the LCST, no adsorbed proteins could be detected even with this ultrasensitive method. Whereas above the LCST, adsorbed protein was detected in amounts corresponding at less than the monolayer. PCA loadings plots showed that adventitious contaminants, which might lead to confounding or misleading spectral changes upon protein exposure, were not observed.