Surface characterization of cholesterol monohydrate single crystals by chemical force microscopy
Surface characterization of cholesterol monohydrate single crystals by chemical force microscopy
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DOI：
10.1021/la025649r
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发表时间：
2002-06-11
期刊：
影响因子：
3.9
通讯作者：
Swift, JA
中科院分区：
文献类型：
--
作者：
Abendan, RS;Swift, JA
原子力显微镜（AFM）和化学力显微镜（CFM）技术已被用来表征胆固醇一水合物单晶表面在不同的溶液环境中的化学功能。人工晶体和天然晶体都具有板状的习性，其中最大的面是（001）。在水溶液和有机溶液的条件下，在原位接触模式的形貌图像显示，板面主要是由双层分子结构终止，因此在很大程度上是均匀的。用化学改性的尖端获得的粘附力测量结果表明，晶体表面的功能可以通过溶液组成的变化而改变。胆固醇分子的3-羟基末端在水介质中呈现在板面上，而烷基尾基在有机溶液中终止于表面。接触角测量（001）表面暴露于不同的亲水性溶剂也显示出类似的趋势，这些AFM分配提供额外的支持。这些研究将分子水平和宏观粘附特性联系起来，并表明溶液环境可以对这种重要生物材料的表面特性产生强烈影响。
Atomic force microscopy (AFM) and chemical force microscopy (CFM) techniques have been used to characterize the chemical functionality of cholesterol monohydrate single-crystal surfaces in different solution environments. Both synthetic and natural crystals adopt a platelike habit in which the largest face is (001). Under aqueous and organic solution conditions, in situ contact mode topographical images reveal that the plate face is primarily terminated by bilayer molecular structures and therefore largely homogeneous. Adhesion force measurements obtained with chemically modified tips demonstrate that the functionality of the crystal surface can be altered by changes in the solution composition. The 3-hydroxyl end of cholesterol molecules is presented on the plate face in aqueous media, while alkyl tail groups terminate the surface in organic solutions. Contact angle measurements on (001) surfaces exposed to solvents of different hydrophilicity also show similar trends, providing additional support to these AFM assignments. These studies link molecular-level and macroscopic adhesion properties and demonstrate that solution environment can exert a strong influence on the surface properties of this important biomaterial.