Design and Fabrication of a Novel Biomass Sensor

Currently, there is immense interest and demand for novel biosensors to detect a growing number of diverse analytes at increasingly low concentrations. Here for the first time, a novel ultra-sensitive MEMS mass sensor is proposed capable of measuring masses in the order of femtogram. The sensor consists of a rotational disk surrounded by a group of moving cantilever beams which are electrostatically excited through the fixed cantilever electrodes. The proposed device will be tested for the detection of alphafetoprotein (AFP), which is a biomarker for liver cancer. The liver cancer is one of the few tumors for which cytotoxic chemotherapy has little effect and this justifies the early-stage diagnosis of it for more survival. The sensitivity, selectivity and detection limit of the biosensor will be determined. We intend to uncover the underlying nonlinear dynamics and reduce the knowledge gap in the field.
The proposed MEMS sensor/switch takes advantage of the in-plane rotational motion to overcome the complications of the out-ofplane motion of traditional cantilever MEMS sensors and accordingly results in enhanced sensitivity in comparison with Quartz Crystal Microbalance technology. Furthermore, considering the ratio of the biomass to the resonator mass the position dependency of the biomass on the cantilever beam becomes more pronounced. Due to the unique architecture of the proposed model, the output of the sensor will be independent of the position of the biomarker and the deposition of the receptor, and the biomarker will not change the stiffness of the sensor. Therefore, the proposed biomass sensor offers a sensitivity beyond the available cantilever-based biomass sensors without the need to scale down to nano regime, which significantly demands higher fabrication costs and increases complexities. This enables the rapid detection of a wide range of biomasses (such as biomarkers associated with different diseases) in real-time and at ultra-high sensitivity.