Exploring the role of molecular chirality in the photo-responsiveness of dipeptide-based gels. Issue 17 (12th April 2017)

• Record Type: Journal Article
• Authors: Chen, Zhonghui; Lv, Ziyu; Qing, Guangyan; Sun, Taolei
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 17(2017)
• Page Start: 3163
• Page End: 3171
• Publication Date: 2017-04-12
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Biomedical materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7tb00402h
• Languages: English
• ISSNs: 2050-750X

Abstract

Abstract : Chiral effect: upon UV light irradiation, thel -gel has a markedly faster gel–sol transition than thed -gel. Abstract : Photo-responsive materials, particularly those based on peptides, hold much promise for numerous potential applications in biomedicine and bionanotechnology. For these switchable materials, one of the key issues is how their photo-response rate can be regulated precisely and reversibly. In this study, we used molecular chirality as a useful tool for modulating the gel–sol response rate of dipeptide-based gels consisting of azobenzene and two dipeptide arms. UV light irradiation triggered the trans -to- cis ( E / Z )-isomerization of azobenzene that destroyed the planar structures of gelators and induced gel collapse. During this process, a distinct gel–sol transition speed was identified for thel -gel andd -gel, and remarkable differences were observed in the self-assembly behavior between thel -gelator and thed -gelator. Mechanistic studies revealed that molecular chirality dominated the rearrangement of the flexible dipeptide linkers, which further affected the competitive balance between E / Z -isomerization and gelation forces driven by π–π stacking among adjacent benzenes, thus resulting in the distinct disassembly behaviors of thel -gel and thed -gel. The remarkable difference in the gel–sol transition speed, good reversibility and the underlying competition mechanism suggest that molecular chirality may be an efficient parameter for regulating the performance of photo-responsive gels and devices.