Quartz crystal biosensor for detection of sugars and glycated hemoglobin

3-Aminophenylboronic acid (APBA) was used for construction of affinity mass sensors for determination of saccharides and glycated hemoglobin using complexation reaction with diol groups. Two approaches were tested for the bioligand layer fabrication-incorporation of APBA inside a thicker matrix and immobilization as a self-assembled monolayer, respectively. The direct affinity sensor with APBA embeded in the structure of glutaraldehyde-crosslinked bovine serum albumine provided linear response to mono- and dissacharides in the range from 0.1 to 15.0 mg/ml. This biosensor was also used for kinetic analysis of the interaction of boronic acid with diols; the values of association and dissociation constants were determined. The sensors with a monolayer of boronic groups were better suited for binding of glycated hemoglobin, probably due to improved steric access to the ligand.