Metal coordination induced disassembly of polypeptides affords electrochemically active hybrid nano-helices

Abstract

Metallopolymers present a class of promising functional materials. The self-assembly of metallopolymers leads to the formation of metal-enriched nanomaterials that offer a variety of potential applications in nano-devices. In this paper, a series of redox active 4-armed star poly(γ-benzyl-L-glutamate) decorated with cyanoferrate complex (PBLG-Fe) was synthesized by combining the ring-opening polymerization of γ-benzyl-L-glutamate with a post-modification procedure. We demonstrate that the incorporation of an appropriate amount of ferrate complex induces hexagonally packed PBLG to disassemble into nano-helices, as confirmed by FT-IR, XRD, CD, DLS and TEM. The PBLG-Fe helices were electrochemically active. The apparent diffusion coefficient (D_m) of the nano-helices increased initially and decreased with increasing ferrate fractions. A maximum D_m was achieved for PBLG-Fe containing a moderate amount of ferrate of 16 wt%. Such metal coordination induced disassembly of polypeptides offers a new avenue to highly anisotropic organometallic nanomaterials.