Electrostatically assembled glycan-immobilized monodisperse copolymer particles for selective lectin adsorption

Glycan-immobilized polymer particles that can selectively separate and recover viruses, bacteria, and toxic proteins are of great interest for medical and public health applications. In this study, we developed a platform for synthesizing highly monodisperse glycan-immobilized polymer particles, which enable the selective adsorption of various lectins by immobilizing different glycans. Key features of this platform are the facile and robust immobilization of glycans onto the polymer particle surface via electrostatic interactions simply by mixing in aqueous solution, as well as the suppression of nonspecific protein adsorption, enabling the selective adsorption of proteins that recognize the immobilized glycans. The monodisperse polymer particles were prepared by aqueous copolymerization of hydrophobic methyl methacrylate and hydrophilic 2-hydroxyethyl methacrylate (HEMA) at a molar ratio of 2:1, using 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride as a cationic radical initiator. The use of HEMA was intended to make the particle surface hydrophilic and suppress nonspecific protein adsorption. Solid-state ¹³C nuclear magnetic resonance analyses confirmed that random copolymer particles were obtained. Glycan-modified sodium poly(γ-glutamate) (γ-PGA), incorporating N,N'-diacetylchitobiose (GN₂), lactose, and sialo-oligosaccharides, formed complexes with particles via electrostatic interactions between the negatively charged carboxyl groups of γ-PGA and the positively charged groups derived from the initiator. The GN₂-γPGA-immobilized particles retained their lectin adsorption ability after storage in water for 6 months, indicating that this approach enables stable, robust glycan immobilization. This platform is expected to facilitate the development of particles that can be used to detect various viruses and bacteria.