Silver ion-histidine interplay switches peptide hydrogel from antiparallel to parallel β-assembly and enables controlled antibacterial activity.

Research paper by Yuchen Y Guo, Sha S Wang, Hanhan H Du, Xiaolong X Chen, Hao H Fei

Indexed on: 20 Dec '18Published on: 20 Dec '18Published in: Biomacromolecules


Understanding the chemical absorption process of silver ions helps the rational design of functional materials for effective release to minimize unwanted toxicity. To this end, a histidine-containing aliphatic peptide (IH6) was designed to immobilize silver ion (Ag) through coordinate interaction. Using circular dichroism spectroscopy, Ag was found to dose-dependently induces parallel β-sheet conformation of IH6 to a saturation molar ratio of 1:2. A conformational switch of IH6 from antiparallel to parallel β-sheet assembly upon Ag coordination was further revealed by Fourier transform infrared spectroscopy. The resultant Ag-IH6 hydrogel displayed substantially enhanced mechanical strength as well as controlled release of Ag. Ag-IH6 hydrogel thus exhibited strong dose-dependent bactericidal activities which can be tuned selective, sparing the co-cultured human keratinocytes in normal. Overall, the study demonstrates an unusual silver ion-induced peptide conformational switch between β-structure subtypes and the bilateral effects on hydrogel-based chemical control of silver ion absorption and release, thus revealing the potential in antibacterial applications.