π–π Interlocking Effect for Designing Biodegradable Nanorods with Controlled Lateral Surface Curvature

Abstract

The morphology of nanoparticles is closely related to their various applications. However, precise control over geometric parameters such as the lateral surface curvature (K) of nanorods still remains an important challenge. To address this issue, we propose a π–π interlocking effect for fabricating biodegradable nanorods with tailored lateral surface curvature. This interlocking effect originates from π–π interactions, provides noncovalent conformational locks among poly-γ-benzyl-l-glutamate (PBLG) chains, and plays a key role in the formation of these nanorods during self-assembly. This interlocking effect can be facilely manipulated by end-group engineering; different α end groups are introduced into PBLG homopolypeptides to afford nanorods with controlled lateral surface curvature. The stronger the π–π interlocking effect, the straighter the lateral surface of nanorods. Furthermore, a co-solvent strategy can be applied to facilely control the aspect ratio (Γ) of the nanorods with a straight lateral surface. Compared with other nanorods that are either based on nonbiodegradable materials or dependent upon complicated cost-consuming processes, this work provides a versatile bottom-up strategy for preparing biodegradable nanorods with controlled lateral surface curvature and aspect ratio.