Sumarokova Maria, Iturri Jagoba, Toca-Herrera José L
Institute for Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna 1190, Austria.
Microsc Res Tech. 2018 Jan;81(1):38-45. doi: 10.1002/jemt.22954. Epub 2017 Oct 7.
Fibronectin is an extracellular matrix protein that is involved in cell adhesion, growth, migration, differentiation, and wound healing. Fibronectin coatings are currently used in many laboratories for biomedical and biotechnology purposes. In this study we have investigated the adhesion and mechanical properties of fibronectin coatings. The coatings were also used to study the role of the residence time and the influence of the loading rate in nonspecific interactions. The results showed that the adhesion force between silica and fibronectin increased with loading rate delivering similar values for residence times of 1 and 2 s. Further analysis indicated that the distance to the transition state was about 0.5 nm. Moreover, the adhesion force did not vary with the loading rate for contact time of 0 s. The unfolding of fibronectin domains also depended of the Dwell time (no unfolding events were observed for zero residence time). Applied loads of 2 nN were able to stretch the fibronectin layer up to 200 nm and to unfold the three fibronectin domains, which were similar for a Dwell time of 1 and 2 s. However, the unfolding length increased with loading rate: below 2.5 µm s the obtained lengths matched the value of FN I (13.5 nm), while for higher speeds the measured values corresponded to the lengths of FN II (18 nm) and FN III (27 nm). This investigation has answered and opened new questions about the mechanical stability and function of fibronectin coatings. The results have also raised theoretical questions about the difference between specific and nonspecific interactions to be addressed in future work.
纤连蛋白是一种细胞外基质蛋白，参与细胞黏附、生长、迁移、分化和伤口愈合。目前，许多实验室将纤连蛋白涂层用于生物医学和生物技术目的。在本研究中，我们研究了纤连蛋白涂层的黏附特性和力学性能。这些涂层还用于研究停留时间的作用以及加载速率在非特异性相互作用中的影响。结果表明，二氧化硅与纤连蛋白之间的黏附力随加载速率增加，在停留时间为1秒和2秒时给出相似的值。进一步分析表明，到过渡态的距离约为0.5纳米。此外，对于接触时间为0秒的情况，黏附力不随加载速率变化。纤连蛋白结构域的展开也取决于停留时间（对于零停留时间未观察到展开事件）。2纳牛顿的外加负载能够将纤连蛋白层拉伸至200纳米，并展开三个纤连蛋白结构域，对于1秒和2秒的停留时间，这些情况相似。然而，展开长度随加载速率增加：在2.5微米/秒以下，获得的长度与纤连蛋白I（13.5纳米）的值匹配，而对于更高速度，测量值对应于纤连蛋白II（18纳米）和纤连蛋白III（27纳米）的长度。这项研究回答并提出了关于纤连蛋白涂层力学稳定性和功能的新问题。研究结果还提出了关于特异性和非特异性相互作用差异的理论问题，有待未来工作解决。
