Effect of Surface Potential on Extracellular Matrix Protein Adsorption

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• 作者：Jiun-Hao Lin ; Hsun-Yun Chang ; Wei-Lun Kao ; Kang-Yi Lin ; Hua-Yang Liao ; Yun-Wen You ; Yu-Ting Kuo ; Ding-Yuan Kuo ; Kuo-Jui Chu ; Yi-Hsuan Chu ; Jing-Jong Shyue
• 刊名：Langmuir
• 出版年：2014
• 出版时间：September 2, 2014
• 年：2014
• 卷：30
• 期：34
• 页码：10328-10335
• 全文大小：581K
• ISSN：1520-5827

文摘

Extracellular matrix (ECM) proteins, such as fibronectin, laminin, and collagen IV, play important roles in many cellular behaviors, including cell adhesion and spreading. Understanding their adsorption behavior on surfaces with different natures is helpful for studying the cellular responses to environments. By tailoring the chemical composition in binary acidic (anionic) and basic (cationic) functionalized self-assembled monolayer (SAM)-modified gold substrates, variable surface potentials can be generated. To examine how surface potential affects the interaction between ECM proteins and substrates, a quartz crystal microbalance with dissipation detection (QCM-D) was used. To study the interaction under physiological conditions, the ionic strength and pH were controlled using phosphate-buffered saline at 37 掳C, and the 味 potentials of the SAM-modified Au and protein were determined using an electrokinetic analyzer and phase analysis light scattering, respectively. During adsorption processes, the shifts in resonant frequency (f) and energy dissipation (D) were acquired simultaneously, and the weight change was calculated using the Kelvin鈥揤oigt model. The results reveal that slightly charged protein can be adsorbed on a highly charged SAM, even where both surfaces are negatively charged. This behavior is attributed to the highly charged SAM, which polarizes the protein microscopically, and the Debye interaction, as well as other short-range interactions such as steric force, hydrogen bonding, direct bonding, charged domains within the protein structure, etc., that allow adsorption, although the macroscopic electrostatic interaction discourages adsorption. For surfaces with a moderate potential, proteins are not significantly polarized by the surface, and the interaction can be predicted through simple electrostatic attraction. Furthermore, surface-induced self-assembly of protein molecules also affects the adsorbed structures and kinetics. The adsorbed layer properties, such as rigidity and packing behaviors, were further investigated using the D鈥?i>f plot and phase detection microscopy (PDM) imaging.