LAUSR

Quartz crystal microbalance (QCM) has attracted extensive attention in the field of biological analysis and detection because of its high sensitivity, fast response, real-time measurement, good operability, and low-cost production. However, the detection of trace amounts of small molecules, such as the detection of low concentrations of salivary glucose under physiological conditions, is still a major challenge. Herein, the surface of a QCM chip was coated with a poly(boronic acid)-based hydrogel using UV pressing-assisted polymerization to obtain a simple device for glucose detection. The designed QCM sensor shows record-low detection limit of glucose (3 mg/L at pH 7.5) among reported boric acid polymer-based QCM sensors, which is about 30 times lower than that of sensors fabricated by conventional surface initiation-spin coating. The outperformance of the poly(boric acid) hydrogel-coated QCM sensor is probably owing to the uniform and compact microstructure, and the presence of sufficient glucose binding sites resulting from the hydrogel coating generated by UV pressing-assisted polymerization. This method provides an important solution for the detection of trace amounts of small organic molecules or ions, and has the potential to push forward the practical applications of QCM sensors.