Fluorescent homopolypeptide toroids. Issue 11 (16th February 2022)

• Record Type: Journal Article
• Authors: Fan, Liujie; Jiang, Jinhui; Sun, Qingmei; Hong, Kai; Cornel, Erik Jan; Zhu, Yunqing; Du, Jianzhong
• Is Part Of: Polymer chemistry. Volume 13:Issue 11(2022)
• Page Start: 1495
• Page End: 1501
• Publication Date: 2022-02-16
• Subjects: Polymers -- Periodicals; Macromolecules -- Periodicals; Polymerization -- Periodicals; 547.705
• DOI: 10.1039/d1py01691a
• Languages: English
• ISSNs: 1759-9954

Abstract

Abstract : Homopolypeptide poly(γ-benzyl-l -glutamate) can self-assemble into fluorescent toroids following an end-to-end closure mechanism. Abstract : Toroids are important ring-like nanostructures in living systems; intrinsically luminogenic toroids are promising in bioimaging but it remains challenging to synthesize such nanoparticles. Herein, we report a fluorescent toroid that is self-assembled from the homopolypeptide poly(γ-benzyl-l -glutamate) (TPE-PBLG28, where TPE refers to the end-group tetraphenylethene and the subscript refers to the degree of polymerization). We found that both water content and temperature are crucial for the formation of toroids during self-assembly. The morphological evolution pathway goes from twisted nanoparticles to curved nanoparticles, and eventually, to toroids; this was analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), etc. This new mechanism of end-to-end closure of twisted nanoparticles that leads to toroids offers new insight for preparing ring-like nanostructures, as it is different from the traditional 'loop-and-wind' route of high molecular weight PBLG. The fluorescent TPE end-group confers the final low cytotoxic toroids suitable for cell imaging. Overall, this work provides insight into a new mechanism for the formation of fluorescent polypeptide toroids.