Quartz thickness shear mode resonators for living cells based functional biosensors

In this study, we investigate the use of quartz thickness shear mode (TSM) resonators to monitor the behavior of human patellar tendon fibroblasts (HPTFs). The quartz resonator used is an AT-cut crystal coated with either gold or indium-tin oxide (ITO). The use of transparent ITO as resonator electrodes enables the combination of the device with a microscope to form a sensor platform. The time dependent information of cell behavior is obtained by monitoring the characteristic frequency shift Δf and the motional resistance change ΔR in real-time. The HPTFs morphology is also monitored simultaneously to correlate with the quantitative sensor responses. Trypsin, which can significantly detach cells from the resonator surface, is used for cell detachment. The experimental study demonstrates that the functional biosensor system with combination of acoustic wave resonators, appropriate biocompatible interface, living cells, mini-incubator and optical microscopy provides a fast, yet quantitative functional biosensing approach for cell adhesion, contraction and other behaviors under controlled biological conditions in real time.