A Thioether‐Bridging Surface Modification of Polymeric Microspheres Offers Nonbiological Protein A‐Mimetic Affinity for IgG

Abstract

AbstractSurface modification of polymeric materials to control their interaction with proteins has been studied extensively, leading to widespread bio‐applications. However, the development of nonbiological, smart polymer surfaces, mimicking the recognition ability of biomolecules, remains a challenge. The present study presents a thioether‐bridging surface modification of polymeric microspheres as a new approach for mimicking protein A affinity for immunoglobulin G (IgG). The bridge‐modified surface is created through an epoxide linking reaction of porous polymeric microspheres with potassium thioacetate in a 2:1 molar ratio, acting as a protein A ligand, which is essential for industrial IgG purification. This surface exhibits buffer responsiveness and selective high‐affinity binding to the IgG Fc region. Remarkably, a comparison among the binding behaviors of a series of thioether‐modified microspheres indicates that bridging structures composed of β,β′‐dihydroxysulfide play a predominant role in IgG recognition. This straightforward approach can lead to the development of economical and practical nonbiological alternatives to protein A‐conjugated materials, providing solutions for various applications such as biosensors and site‐specific reagents utilizing the affinity of the IgG Fc region. The improved understanding of protein interactions at bridged/non‐bridged interfaces can be valuable in various applications such as implant materials and biomaterials.