Boronic acid-modified thin film interface for specific binding of glycated hemoglobin (HbA1c) and electrochemical biosensing

We studied electrochemical detection of glycated hemoglobin (HbA1c) using boronic acid-modified electrodes. Boronic acid is known to form covalent bonds between its diol group and cis-diol group of the carbohydrate chain. Therefore, to detect HbA1c, boronic acid was functionalized on the chemically modified electrode surface using poly(amidoamine) G4 dendrimer as an interface material. HbA1c was biospecifically attached to the chip surface through the cis-diol interaction between peripheral glucose from HbA1c and functionalized boronic acid. To confirm the HbA1c binding to the boronic acid layer, periodate-treated glucose oxidase (GOx) was backfilled to the remaining amine groups of dendrimer on the electrode surface and quantified electrochemically. A sensitive decrement of the current was achieved with increasing percentile concentration from 2.5% to 15% HbA1c per total hemoglobin. This method has potential not only to determine HbA1c concentration but also to determine the concentrations of a variety of glycoproteins that contain peripheral sugar groups.