Surface modification of polydopamine coated particles via glycopolymer brush synthesis for protein binding and FLIM testing

Abstract

Glycopolymer brushes were successfully synthesized on polydopamine coated silicon dioxide particles using a one-step ‘grafting from’ method to produce high density polymer brushes. This one-step ‘grafting from’ method uses an azide-terminated RAFT agent that simultaneously grows polymer chains and attaches to the polydopamine coating. The azide group rearranges via an in situ Curtius rearrangement to form an isocyanate group. This reacts with the hydroxyl and amine groups on the polydopamine coating while simultaneously growing a polymer chain. Poly(pentafluorostyrene) polymer brushes were grown and attached to the polydopamine coating, then converted to glycopolymer brushes using a thiol substitution reaction. This creates a surface that facilitates protein binding. Fluorescently tagged Concanavalin A proteins were bound to the surface and the binding ability was investigated using Fluorescence Lifetime Imaging Microscopy (FLIM). This reports the facile preparation of particles that are biocompatible, and can be used in vivo as drug carrier systems. The use of polydopamine coatings, one-step ‘grafting from’ polymer brush synthesis and ‘click’ chemistry to create glycopolymers, collectively are an improved and simple way to prepare particles for biomedical applications.