Molecular packing of lysozyme, fibrinogen, and bovine serum albumin on hydrophilic and hydrophobic surfaces studied by infrared-visible sum frequency generation and fluorescence microscopy
Molecular packing of lysozyme, fibrinogen, and bovine serum albumin on hydrophilic and hydrophobic surfaces studied by infrared-visible sum frequency generation and fluorescence microscopy
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DOI：
10.1021/ja028987n
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发表时间：
2003-03-12
影响因子：
15
通讯作者：
Somorjai, GA
中科院分区：
文献类型：
--
作者：
Kim, J;Somorjai, GA
利用红外-可见和频产生（SFG）振动光谱技术，结合荧光显微镜技术，研究了溶菌酶、纤维蛋白原和牛血清白蛋白（BSA）在亲水性二氧化硅和疏水性聚苯乙烯上吸附的表面结构与蛋白质浓度的关系。荧光显微镜显示，吸附在亲水和疏水表面上的蛋白质的相对量与蛋白质溶液的浓度成比例地增加。对于给定的本体蛋白质浓度，与亲水性二氧化硅表面相比，更大量的蛋白质吸附在疏水性聚苯乙烯表面上。虽然吸附在二氧化硅表面上的溶菌酶分子产生相对相似的SFG光谱，无论表面浓度，SFG光谱的纤维蛋白原和BSA吸附在二氧化硅表面上表现出浓度依赖性的信号强度和峰形。定量SFG数据分析表明，甲基基团在溶菌酶吸附在亲水性表面上显示出浓度无关的取向。然而，BSA和纤维蛋白原中的甲基随着表面处蛋白质浓度的增加而相对于表面法线变得不那么倾斜。在疏水聚苯乙烯表面上，所有蛋白质产生类似的SFG光谱，这是不同于亲水表面上的那些。虽然更多的蛋白质分子存在于疏水表面上，但观察到较低的SFG信号强度，表明吸附的蛋白质中的甲基基团比亲水表面上的那些更随机取向。SFG数据还表明，在聚苯乙烯表面的苯环的取向和排序的影响，蛋白质吸附，这取决于蛋白质的量和类型。
Infrared-visible sum frequency generation (SFG) vibrational spectroscopy, in combination with fluorescence microscopy, was employed to investigate the surface structure of lysozyme, fibrinogen, and bovine serum albumin (BSA) adsorbed on hydrophilic silica and hydrophobic polystyrene as a function of protein concentration. Fluorescence microscopy shows that the relative amounts of protein adsorbed on hydrophilic and hydrophobic surfaces increase in proportion with the concentration of protein solutions. For a given bulk protein concentration, a larger amount of protein is adsorbed on hydrophobic polystyrene surfaces compared to hydrophilic silica surfaces. While lysozyme molecules adsorbed on silica surfaces yield relatively similar SFG spectra, regardless of the surface concentration, SFG spectra of fibrinogen and BSA adsorbed on silica surfaces exhibit concentration-dependent signal intensities and peak shapes. Quantitative SFG data analysis reveals that methyl groups in lysozyme adsorbed on hydrophilic surfaces show a concentration-independent orientation. However, methyl groups in BSA and fibrinogen become less tilted with respect to the surface normal with increasing protein concentration at the surface. On hydrophobic polystyrene surfaces, all proteins yield similar SFG spectra, which are different from those on hydrophilic surfaces. Although more protein molecules are present on hydrophobic surfaces, lower SFG signal intensity is observed, indicating that methyl groups in adsorbed proteins are more randomly oriented as compared to those on hydrophilic surfaces. SFG data also shows that the orientation and ordering of phenyl rings in the polystyrene surface is affected by protein adsorption, depending on the amount and type of proteins.