Ni Rong, Liu Jianhui, Chau Ying
Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China
Institute for Advanced Study, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China.
RSC Adv. 2018 Aug 20;8(51):29482-29487. doi: 10.1039/c8ra04391d. eCollection 2018 Aug 14.
In this report, we investigated the impact of external stimulus (ultrasound) and internal stimulus (pH) on peptide assembly and disassembly. Two short rationally designed peptides K3C6SPD and F20H differing in the presence of a single pH-sensitive histidine residue were studied as the model peptides. The assembly kinetics studies demonstrated that the substitution of phenylalanine in K3C6SPD with histidine (F20H) significantly slowed down the peptide assembly rate at all three tested pHs (pH 9.5, pH 7.4 and pH 5.0). At the same time, this F to H substitution led to the increased pH-responsive assembly kinetics. By treating the peptide sample at the beginning of the assembly process at pH 9.5 for 5 min with the ultrasound power of 2.1 W cm, the assembly rate of peptide F20H was significantly accelerated with the lag phase being shortened from 10 days to 2 days. For the disassembly of F20H peptide nanofibrils preformed at pH 9.5, upon pH adjustment from pH 9.5 to pH 5.0, 5 min ultrasonication of the nanofibrils resulted in the nanofibril disassembly within 6 hours, instead of 5 days in the absence of ultrasound. On the contrary, similar ultrasound treatment of the peptide K3C6SPD did not produce any obvious effect on both assembly and disassembly processes. This study offers an effective strategy to modulate the stimuli-responsiveness of the peptide-based biomaterials.
在本报告中，我们研究了外部刺激（超声）和内部刺激（pH值）对肽组装和解组装的影响。研究了两种经合理设计的短肽K3C6SPD和F20H，它们仅在一个对pH敏感的组氨酸残基的存在上有所不同，以此作为模型肽。组装动力学研究表明，在K3C6SPD中将苯丙氨酸替换为组氨酸（F20H），在所有三个测试pH值（pH 9.5、pH 7.4和pH 5.0）下均显著减慢了肽的组装速率。同时，这种F到H的替换导致了pH响应组装动力学的增加。在组装过程开始时，用2.1 W/cm的超声功率在pH 9.5下处理肽样品5分钟，肽F20H的组装速率显著加快，滞后阶段从10天缩短至2天。对于在pH 9.5下预先形成的F20H肽纳米纤维的解组装，当pH值从pH 9.5调节到pH 5.0时，对纳米纤维进行5分钟超声处理会导致纳米纤维在6小时内解组装，而在没有超声的情况下则需要5天。相反，对肽K3C6SPD进行类似的超声处理对组装和解组装过程均未产生任何明显影响。本研究提供了一种有效的策略来调节基于肽的生物材料的刺激响应性。
