Synthesis of Comb-like and Coil-Comb Polystyrene–Polyglycidol Copolymers via Click Chemistry: Self-Assembly and Biological Evaluation

TL;DR

This paper explores how different polymer structures affect the formation and safety of polystyrene-polyglycidol micelles for potential biomedical use.

Contribution

The study directly compares comb-like and coil-comb architectures in polystyrene–polyglycidol copolymers with identical polyglycidol content.

Findings

Comb-like and coil-comb copolymers formed stable micelles with similar critical micelle concentrations.

Block-based coil-comb copolymers led to bimodal micellar size distributions.

Both copolymers showed low cytotoxicity and no significant neurotoxic effects in rat brain fractions.

Abstract

Amphiphilic copolymers based on polystyrene and polyglycidol combine the chemical inertness of polystyrene with the biocompatibility of polyglycidol, making them attractive materials for polymeric micelles. While comb-like architectures have been explored to control micellization behavior and biological response, a direct comparison between comb-like and coil-comb topologies in polystyrene–polyglycidol copolymers at identical polyglycidol content remains insufficiently investigated. In this work, amphiphilic comb-like and coil-comb polystyrene–polyglycidol copolymers were synthesized via copper-catalyzed azide–alkyne click chemistry by grafting a monoalkyne-terminated polyglycidol precursor onto azide-functionalized random and block styrene copolymers. The copolymers were characterized by size exclusion chromatography and nuclear magnetic resonance. Polymeric micelles were prepared by nanoprecipitation, and their self-assembly in aqueous solution was investigated by critical micelle concentration determination, dynamic and electrophoretic light scattering, and atomic force microscopy. Both copolymers formed stable aqueous dispersions and exhibited comparable critical micelle concentrations. At identical polyglycidol content, the random copolymer formed a uniform, monomodal micellar population, whereas the block-based coil-comb architecture led to bimodal size distributions, indicating the coexistence of two distinct micellar populations. The investigated systems showed low cytotoxicity and did not induce significant oxidative stress within the studied concentration range. On isolated rat brain sub-cellular fractions (synaptosomes, mitochondria and microsomes), administered alone, the comb-like and coil-comb polystyrene-polyglycidol copolymers did not reveal statistically significant neurotoxic effects. The results demonstrate that macromolecular architecture plays a key role in governing micellar organization and in vitro biological response in polystyrene–polyglycidol copolymers, highlighting their potential as architecture-controlled polymer-based nanocarriers.

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