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Water adsorption and desorption on chemically inert, biorepulsive surfaces

化学惰性、生物排斥表面上的水吸附和解吸

基本信息

批准号：
254232823
负责人：
Dr. Alexei Nefedov
金额：
--
依托单位：
Forschungsgruppe für Angewandte Physikalische Chemie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/254232823?language=en
关键词：
Water adsorption desorption chemically inert

项目摘要

The main objective of the proposed project is a better understanding of the mechanism behind the inertness of poly- and oligo(ethylene glycol) (PEG and OEG, respectively) based organic surfaces to protein adsorption and biofouling. Assuming, in accordance with the most accepted viewpoint, that the key factor behind these properties is hydration of the PEG/OEG moieties, we plan a systematic study of the kinetics and thermodynamics of water adsorption and desorption on a series of model OEG surfaces as well as investigation of the wetting and nucleation behavior of water during the adsorption. As suitable test systems we will take a series of self-assembled monolayers (SAMs) of OEG substituted alkanethiolates (OEG-ATs) on gold and silver substrates. The biorepulsive properties of these monolayers will be tuned in a well-controlled fashion by either varying the length of the OEG segments or by changing their packing density and diluting the OEG-AT moieties with other species. The above changes will be performed in such a way that the macroscopic wetting properties of the target surfaces will be kept constant or vary slightly only, which should make possible to untangle the hydration and subsequent interfacial wetting. Additionally, the terminal group of the OEG-AT SAMs will be varied to obtain a further tool to untangle hydration and interfacial wetting. A particular attention will be paid to the nucleation behavior of water and to the initial stages of adsorption, where the hydration should play the dominant role since the adsorption of water should first occur in the form of hydration of the OEG part of the OEG-ATs SAMs followed by the formation of the ice film at the SAM-ambience interface (interfacial phase). Varying the water coverage and systematically varying the capability of hydration by design of the OEG-ATs molecules and respective SAMs, we should be able to monitor the transfer from the hydration to wetting regime as well as to distinguish between the hydration and interfacial phases and to derive specifically their parameters. The observed behavior and derived kinetic and thermodynamic parameters as well as extent of hydration, etc., will be correlated with the proneness or inertness of the OEG-AT SAMs to protein adsorption and biofouling. Finally, using several complementary spectroscopic techniques, information about the binding configuration of the water molecules in the hydration phase and their structure and morphology in the interfacial phase will be derived. In addition, we plan to monitor the changes in the structure and conformation of the OEG segments at the initial stages of the water adsorption. The experimental results and derived parameters will be compared with predictions of available theoretical simulations, both as a test of correctness of the respective models and as a means to stimulate a further improvement and development of theory.

拟议项目的主要目标是更好地了解聚乙二醇和低聚乙二醇（PEG和OEG，分别）为基础的有机表面蛋白质吸附和生物污垢的惰性背后的机制。假设，按照最被接受的观点，这些属性背后的关键因素是水合的PEG/OEG部分，我们计划一个系统的动力学和热力学的水的吸附和解吸的一系列模型OEG表面以及调查的润湿和成核行为的水在吸附过程中的研究。作为合适的测试系统，我们将采取一系列的自组装单分子膜（SAMs）的OEG取代的烷基硫醇盐（OEG-AT）的金和银基板。这些单层的生物排斥特性将通过改变OEG片段的长度或通过改变它们的堆积密度和用其他物质稀释OEG-AT部分以良好控制的方式进行调节。上述变化将以这样的方式进行，即目标表面的宏观润湿性质将保持恒定或仅略有变化，这应该能够解开水合和随后的界面润湿。此外，OEG-AT SAM的端基将变化以获得解开水合和界面润湿的进一步工具。将特别注意水的成核行为和吸附的初始阶段，其中水合作用应发挥主导作用，因为水的吸附应首先发生在水合的OEG部分的OEG-AT的自组装膜的形式，然后由冰膜的形成在自组装膜-环境界面（界面相）。通过设计OEG-AT分子和相应的SAM，改变水的覆盖率和系统地改变水合能力，我们应该能够监测从水合到润湿状态的转移，以及区分水合和界面相，并具体推导出它们的参数。观察到的行为和推导的动力学和热力学参数以及水合程度等，将与OEG-AT自组装膜对蛋白质吸附和生物污垢的倾向性或惰性相关。最后，使用几种互补的光谱技术，信息的结合配置的水分子在水合相和它们的结构和形态在界面相将被导出。此外，我们计划监测在水吸附的初始阶段的OEG片段的结构和构象的变化。实验结果和导出的参数将与可用的理论模拟的预测进行比较，既作为各自模型的正确性的测试，也作为刺激理论的进一步改进和发展的手段。