Wang Min Sze, Palmer Laura B, Schwartz Jay D, Razatos Anneta
Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287-6006, USA.
Langmuir. 2004 Aug 31;20(18):7753-9. doi: 10.1021/la049849+.
Failure of implanted biomaterials is commonly due to nonspecific protein adsorption, which in turn causes adverse reactions such as the formation of fibrous capsules, blood clots, or bacterial biofilm infections. Current research efforts have focused on modifying the biomaterial interface to control protein reactions. Designing biomaterial interfaces at the molecular level, however, requires an experimental technique that provides detailed, dynamic information on the forces involved in protein adhesion. The goal of this study was to develop an atomic force microscope (AFM)-based technique to evaluate protein adhesion on biomaterial surfaces. In this study, the AFM was used to evaluate (i) protein-protein, (ii) protein-substrate, and (iii) protein-dextran interactions. The AFM was first used to measure the pull-off forces between bovine serum albumin (BSA) tips/BSA surfaces and BSA tips/anti-BSA surfaces. Results from these protein-protein studies were consistent with the literature. More importantly, the successful measurement of antibody-antigen binding interactions demonstrates that both the BSA and anti-BSA proteins retain their folded conformation and remain functional following our immobilization protocol. The AFM was also used to quantify the physiochemical interactions of proteins during adhesion to various self-assembled monolayers (SAMs) and dextran-coated substrates representative of potential biomaterial interface modifications. Dextran, which renders surfaces very hydrophilic, was the only surface coating that BSA protein did not adhere to. Hydrophobic interactions were not found to play a significant role in BSA adhesion. Therefore, the dextran molecules may resist protein adhesion by repulsive steric effects or hydration pressure. Moreover, the AFM-based methodology provides dynamic, quantitative information about protein adhesion at the nanoscale level.
植入生物材料的失效通常是由于非特异性蛋白质吸附，这反过来又会引发诸如纤维囊形成、血栓或细菌生物膜感染等不良反应。目前的研究工作主要集中在修饰生物材料界面以控制蛋白质反应。然而，在分子水平设计生物材料界面需要一种能够提供有关蛋白质粘附所涉及力的详细动态信息的实验技术。本研究的目的是开发一种基于原子力显微镜（AFM）的技术来评估蛋白质在生物材料表面的粘附情况。在本研究中，AFM被用于评估（i）蛋白质-蛋白质、（ii）蛋白质-底物和（iii）蛋白质-葡聚糖相互作用。AFM首先用于测量牛血清白蛋白（BSA）针尖/BSA表面以及BSA针尖/抗BSA表面之间的拉脱力。这些蛋白质-蛋白质研究的结果与文献一致。更重要的是，抗体-抗原结合相互作用的成功测量表明，在我们的固定化方案之后，BSA和抗BSA蛋白都保持其折叠构象并保持功能。AFM还用于量化蛋白质在粘附到各种自组装单分子层（SAMs）和代表潜在生物材料界面修饰的葡聚糖包被底物过程中的物理化学相互作用。葡聚糖使表面具有很强的亲水性，是BSA蛋白唯一不粘附的表面涂层。未发现疏水相互作用在BSA粘附中起重要作用。因此，葡聚糖分子可能通过排斥空间效应或水合压力来抵抗蛋白质粘附。此外，基于AFM的方法提供了关于纳米级蛋白质粘附的动态、定量信息。
