Reusable high-frequency electrodeless QCM biosensor with a bare quartz resonator embedded in a silicon microchannel

We present high-frequency electrodeless quartz crystal microbalance (QCM) chip with a bare quartz resonator encapsulated in a silicon microchannel. There is no issue about destruction on assembly because handling the fragile quartz resonator becomes unnecessary. In addition, it is possible to reuse the device, because the quartz surfaces can adsorb receptor proteins non-specifically, which can be removed by the washing procedure with a strong acid solution flowed in the microchannel. We succeeded in detecting the human immunoglobulin G (hIgG) at a concentration of 6 ug/ml via the staphylococcal protein A (SPA) immobilized non-specifically on the developed QCM chip in real time without any labeling.