A quartz crystal microbalance-based biosensor for enzymatic detection of hemoglobin A1c in whole blood

Here we present a quartz crystal microbalance (QCM) biosensor for enzymatic detection of hemoglobin A1c (HbA1c). It shows average plasma glucose concentration readings over the prior three months. HbA1c can be quantitatively measured based on changes of resonance frequency of QCM following mass changes on QCM sensor surface. These mass changes were caused by size enlargement of conjugated gold nanoparticle with thiol-terminated SAMs on the sensor surface due to gold staining by hydrogen peroxide (H2O2) generated from enzymatic HbA1c assay. Finally, we investigated sensor responses due to mass changes on various concentrations of applied H2O2. We also demonstrated its capability for analyzing HbA1c in whole blood sample with enzymatic assay. Our results showed that the proposed QCM biosensor could quantitatively analyze HbA1c with a detection limit of 0.147% HbA1c with respect to hemoglobin and a coefficient variation of less than 10%.