Boronate-functionalized hydrogel as a novel biosensing interface for the glycated hemoglobin A1c (HbA1c) based on the competitive binding with signaling glycoprotein.

According to recent increases in public healthcare costs associated with diabetes mellitus, the development of new glycemic monitoring techniques based on the biosensing of glycated hemoglobin A1c (HbA1c), a promising long-term glycemic biomarker, has become a major challenge. In the development of HbA1c biosensors for point-of-care applications, the selection of an effective biorecognition layer that provides a high reaction yield and specificity toward HbA1c is regarded as the most significant issue. To address this, we developed a novel HbA1c biosensing interfacial material by the integration of boronate hydrogel with glass fiber membrane. In the present study, a new boronate-functionalized hydrogel was designed and spatio-selectively photopolymerized on a hydrophilic glass fiber membrane by using N-hydroxyethyl acrylamide, 3-(acrylamido)phenylboronic acid, and bis(N,N'-methylene-bis-acrylamide). Using this approach, the boronic acid group, which specifically recognizes the cis-diol residue of glucose on the HbA1c molecule, can be three-dimensionally coated on the surface of the glass fiber network with a high density. Because this network structure of boronate hydrogel-grafted fibers enables capillary-driven fluid control, facile HbA1c biosensing in a lateral flow assay concept could be accomplished. On the proposed HbA1c biosensing interface, various concentrations of HbA1c (5-15%) in blood-originated samples were sensitively measured by a colorimetric assay using horseradish peroxidase, a glycoenzyme can generate chromogenic signal after the competitive binding against HbA1c to the boronic acid residues. Based on the demonstrated advantages of boronate hydrogel-modified membrane including high analytical performance, easy operation, and cost-effectiveness, we expect that the proposed biorecognition interfacial material can be applied not only to point-of-care HbA1c biosensors, but also to the quantitative analysis of other glycoprotein biomarkers.