Research On Application Of MOSFET-based Biosensor In Biochemical Detection

Biosensing technology is the frontier technology of the modern information society.It is a research field formed by the infiltration of various disciplines such as biology,chemistry,medicine,physics,and electronics.It has been highly valued and widely used in medical diagnosis,environmental monitoring,food industry and other fields,and has developed rapidly in recent years.Among them,the silicon nanowire field-effect biosensor has become a representative of a new generation of biosensors due to the advantages of both nanomaterials and field effect devices.Silicon nanowire field-effect biosensors can respond to changes in electrical signals caused by molecular binding on the surface of silicon nanowires quickly and in real time.At the same time,no additional labeling signal is required for detection,thereby enabling real-time label-free detection.In addition,it also has the advantages of high sensitivity,good selectivity,fast analysis speed,low reagent consumption,simple operation,etc.,and it has broad space in practical applications.In this paper,we focus on improving the application of sensors in biochemical detection by optimizing the performance of SiNW-FET biosensors.including fabrication of ultra-small size silicon nanowire arrays,selection of dielectric layers,and improvement of surface functionalization schemes of silicon nanowires.The sinw biosensor obtained by the optimized process was used to detect sulfonamides with high sensitivity and to verify the car-t targeted new drugs.The main research contents and results of this paper are as follows:1. Silicon nanowire arrays with high efficiency and uniform consistency were designed and prepared by Self-Aligned Double Patterning?SADP?technology compatible with CMOS process.Meanwhile,its metal contact electrode was designed and optimized,and a high-k HfO₂ dielectric layer of 2-4 nm was deposited to enhance the sensitivity of the nanowire biosensor.2. The device was surface functionalized by O₂ plasma treatment of the high-k HfO₂ dielectric layer and combined with the traditional modification scheme of APTES?glutaraldehyde to achieve antibody immobilization.The experimental results show that the sensitivity of high-k HfO₂ dielectric layer is increased by 3.15 times after O₂ plasma treatment,which is the innovation of this paper.3. The SiNW-FET biosensor was applied to the biochemical detection of sulfadiazine drugs.The measurement of electrical properties showed that the sensor achieved real-time,rapid,highly sensitive and highly specific detection of sulfadiazine drugs,the detection limit was as low as 10 pg/ml,and the sensor showed good specificity.4. Meanwhile,the effects of CAR-T cells and tumor cells were tested by SiNW-FET biosensor.The experimental results show that the sensor can test the signal information of the interaction between cells,and has the advantages of short detection time and high sensitivity compared with traditional fluorescent immunoassay methods,and can be used for CAR-T targeted new drug evaluation to predict Risk of Cytokine Storms.