Key of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China.
Acc Chem Res. 2021 Aug 3;54(15):3016-3027. doi: 10.1021/acs.accounts.1c00231. Epub 2021 Jul 20.
Protein thin films (PTFs) with tunable structure and function can offer multiple opportunities in various fields such as surface modification, biomaterials, packaging, optics, electronics, separation, energy, and environmental science. Although nature may offer a variety of examples of high-level control of structure and function, e.g., the S layer of cells, synthetic alternatives for large-area protein-based thin films with fine control over both biological function and material structure are a key challenge, especially when aiming for facile, low-cost, green, and large-scale preparation as well as a further extension of function, such as the encapsulation and release of functional building blocks.Therefore, regarding the structure and function of PTFs, we will first briefly comment on the problems associated with PTF fabrication, and then, regarding the basis of our long-term research on protein-based thin films, we will summarize the new strategies that we have developed in recent years to explore and control the structure and function of PTFs for frontier research and practical applications.Inspired by naturally occurring protein amyloid fibrillization, we proposed the amyloid-like protein aggregation strategy to assemble proteins into supramolecular 2D films with extremely large sizes and enduring interfacial adhesion stability. This approach opened a new window for PTF fabrication in which the spontaneous interfacial 2D aggregation of protein oligomers instead of traditional 1D protofibril elongation directs the assembly of proteins. As a result, the film morphology, thickness, porosity, and function can be tailored by simply tuning the interfacial aggregation pathways.We further modified amyloid-like protein aggregation to develop chemoselective reaction-induced protein aggregation (CRIPA). It is well known that chemoselective reactions have been employed for protein modification. However, the application of such reactions in PTF fabrication has been overlooked. We initiated this new strategy by employing thiol-disulfide exchange reactions. These reactions are chemoselective toward proteins containing specific disulfide bonds with high redox potentials, resulting in amyloid-like aggregation and thin film formation. Functional proteins with immunity to such reactions can be encapsulated in thin films and released on demand without a loss of activity, opening a new avenue for the development of functional PTFs and coatings.Finally, the resultant amyloid-inspired PTFs, as a new type of biomimetic materials, provide a good platform for integration with various biomedical functions. Here, the creation of bioactive surfaces on virtually arbitrary substrates by amyloid-like PTFs will be discussed, highlighting antimicrobial, antifouling, molecular separation, and interfacial biomineralization activities that exceed those of their native protein precursors and synthetic alternatives.
蛋白质薄膜（PTFs）具有可调节的结构和功能，可以在表面改性、生物材料、包装、光学、电子、分离、能源和环境科学等多个领域提供多种机会。尽管自然界可能提供了多种高级结构和功能控制的例子，例如细胞的 S 层，但具有精细控制生物功能和材料结构的大面积蛋白质基薄膜的合成替代品仍然是一个关键挑战，尤其是在追求简便、低成本、绿色和大规模制备以及进一步扩展功能（例如封装和释放功能构建块）时。因此，关于 PTFs 的结构和功能，我们将首先简要评论与 PTFs 制造相关的问题，然后，基于我们长期研究蛋白质基薄膜的基础，总结我们近年来开发的新策略，以探索和控制 PTFs 的结构和功能，用于前沿研究和实际应用。受天然存在的蛋白质淀粉样纤维形成的启发，我们提出了类似淀粉样蛋白的聚集策略，将蛋白质组装成具有极大尺寸和持久界面粘附稳定性的超分子二维薄膜。这种方法为 PTFs 的制造开辟了一个新的窗口，其中蛋白质低聚物的自发界面二维聚集而不是传统的 1D 原纤维伸长来指导蛋白质的组装。因此，通过简单地调整界面聚集途径，可以定制薄膜的形态、厚度、孔隙率和功能。我们进一步修改了类似淀粉样蛋白的聚集，开发了化学选择性反应诱导的蛋白质聚集（CRIPA）。众所周知，化学选择性反应已被用于蛋白质修饰。然而，这种反应在 PTFs 制造中的应用一直被忽视。我们通过使用巯基-二硫键交换反应来启动这种新策略。这些反应对具有高氧化还原电位的特定二硫键的蛋白质具有化学选择性，导致类似淀粉样的聚集和薄膜形成。对这些反应具有免疫力的功能蛋白可以封装在薄膜中，并在需要时按需释放，而不会失去活性，为功能 PTFs 和涂层的开发开辟了新途径。最后，所得的类似淀粉样的 PTFs 作为一种新型仿生材料，为与各种生物医学功能的集成提供了良好的平台。在这里，将讨论通过类似淀粉样 PTFs 在几乎任意基底上创建生物活性表面，突出其抗菌、抗污、分子分离和界面生物矿化活性超过其天然蛋白质前体和合成替代品。
