Boronic acid-functionalized spherical polymer brushes for efficient and selective enrichment of glycoproteins

Glycoproteins are related to many biological activities and diseases, and thereby their efficient capture and enrichment for diagnostics and proteomics have emerged to exhibit great significance. However, the lack of materials with high binding capacity and selectivity is still a big obstacle for further application. Herein, we reported a facile and eco-friendly approach to fabricate spherical polymer brushes with multiple boronic acid groups. Specifically, the whole process can be divided into three steps, the polystyrene (PS) core was obtained by traditional emulsion polymerization, followed by immobilization of a home-made photoinitiator. Subsequently, boronic acid-functionalized polymer chains (PBA) were chemically grafted via photo-emulsion polymerization, leading to spherical polymer brushes (PS-PBA) with boronate affinity. The particle size, morphology, and composition of as-prepared spherical polymer brushes were systematically characterized. The characteristics of glycoproteins binding to the spherical polymer brushes under different conditions, including pH values and ionic strength, were also investigated. PS-PBA brushes possess fast binding speed (30 min) and high binding capacity for glycoprotein ovalbumin (OVA) (377.0 mg g(-1)) under physiological pH conditions at 25 degrees C, because the low steric hindrance of flexible polymeric PBA chains facilitates the interaction between boronic acid groups and glycoproteins. Moreover, the binding capacity of PS-PBA brushes for glycoprotein OVA was similar to 6.7 times higher than that for non-glycoprotein bovine serum albumin (BSA), indicating the excellent selective adsorption. This study provided a facile and efficient approach for the fabrication of boronic acid-functionalized materials that will be useful in the enrichment and separation of glycoproteins for the diagnosis of diseases.

Automated summary

Glycoproteins are important in biological activities and disease diagnosis, and a facile and eco-friendly method to fabricate spherical polymer brushes with multiple boronic acid groups for glycoprotein separation has been developed. The material shows fast binding speed and high capacity for glycoproteins under physiological conditions, indicating potential for disease diagnosis.