Ho C H, Britt D W, Hlady V
Department of Materials Science and Engineering, University of Utah, Salt Lake City 84112, USA.
J Mol Recognit. 1996 Sep-Dec;9(5-6):444-55. doi: 10.1002/(sici)1099-1352(199634/12)9:5/6<444::aid-jmr281>3.0.co;2-i.
The adsorption of low density lipoprotein (LDL) and human serum albumin (HSA) to model surfaces of different hydrophobicities has been studied using two, surface-sensitive, real-time, in situ techniques: total internal reflection fluorescence (TIRF) and scanning force microscopy (SFM). The model surfaces used were: (1) hydrophilic negatively charged silica (TIRF) and mica (SFM) surfaces, (2) hydrophobic octadecyldimethylsilyl-(ODS)-modified silica (TIRF) and ODS-modified oxidized silicon (SFM) surfaces and (3) amphiphilic ODS-silica gradient surfaces (TIRF). The kinetics of fluorescein isothiocyanate-LDL adsorption onto the ODS-silica gradient surface from FITC-LDL solution and from a solution mixture of LDL and HSA showed that a transport-limited process on the clean silica changed into an adsorption-limited process with increasing surface coverage of ODS chains. SFM analysis of the in situ adsorption of LDL on hydrophilic mica demonstrated a steady increase in surface coverage with time which was somewhat lower than determined by TIRF for FITC-LDL adsorption on silica. The adsorption behavior of a binary mixture of HSA and LDL suggested that lateral interactions between HSA and LDL affect the adsorption process. The diameter of LDL adsorbed on mica and ODS-modified silicon has been determined using SFM to be approximately 55 nm. Tetrameric LDL aggregates were observed on all of the surfaces in addition to some dimers and trimers. Imaging LDL and HSA adsorption on clean oxidized silicon surfaces using "contact mode' SFM techniques was hindered by probe manipulation of the proteins.
全内反射荧光（TIRF）和扫描力显微镜（SFM），研究了低密度脂蛋白（LDL）和人血清白蛋白（HSA）在不同疏水性模型表面上的吸附情况。所使用的模型表面有：（1）亲水性带负电荷的二氧化硅（TIRF）和云母（SFM）表面；（2）疏水性十八烷基二甲基甲硅烷基（ODS）修饰的二氧化硅（TIRF）和ODS修饰的氧化硅（SFM）表面；（3）两亲性ODS-二氧化硅梯度表面（TIRF）。异硫氰酸荧光素-LDL从FITC-LDL溶液以及从LDL和HSA的混合溶液吸附到ODS-二氧化硅梯度表面的动力学表明，在清洁二氧化硅表面上的传输受限过程随着ODS链表面覆盖率的增加转变为吸附受限过程。SFM对LDL在亲水性云母上的原位吸附分析表明，表面覆盖率随时间稳步增加，这略低于TIRF测定的FITC-LDL在二氧化硅上的吸附情况。HSA和LDL二元混合物的吸附行为表明，HSA和LDL之间的横向相互作用会影响吸附过程。利用SFM测定吸附在云母和ODS修饰硅上的LDL直径约为55nm。除了一些二聚体和三聚体外，在所有表面上都观察到了四聚体LDL聚集体。使用“接触模式”SFM技术对清洁氧化硅表面上的LDL和HSA吸附进行成像时，蛋白质的探针操作会产生干扰。
