Study On Differential Graphene Field Effect Transistor Biomolecules Sensor

In recent years,the prevalence of chronic diseases has increased dramatically,threatening human health and affecting people’s quality of life.The existing clinical detection technology is expensive and time-consuming,which cannot realize the low-cost and rapid detection of chronic diseases.Graphene Field Effect Transistor(GFET)biomolecular sensor has the advantage of high sensitivity and fast response,which has broad application prospects in disease prevention and diagnosis.This paper studys on the differential GFET biomolecular sensor based on GFET biosensors at this stage of research,and designs a differential GFET sensor for portable detection of biomolecules.This paper analyzes the electrical characteristics and sensing principle of GFET,determines the sensing detection range,and establishes the mathematical model of the differential GFET sensor response signal,so as to establish the quantitative relationship between the output of GFET and the concentration of target molecule.This paper designs the dual-channel differential GFET structure of detection channel and reference channel.The detection channel modifies the target molecular probe to identify the weak detection signal of the doping interference.The reference channel does not modify the target molecular probe to identify the interference signal.This paper makes a difference between them using compensation check method,getting detection signals related to the concentration of the target molecule,so as to reduce external interference.Differential sensor processing is carried out by means of micro-nano processing technology,such as transfer,lithography,gold plating and oxygen ion etching.At the same time,the low-noise differential amplifier circuit is designed to collect the weak current signal from the differential GFET sensor,and carry out differential amplification and other mathematical processing.The front-end differential GFET sensor is connected with the back-end low-noise amplifier circuit to make differential GFET portable detection equipment.In this paper,the Aptameric GFET sensor and Boric acid GFET sensor are the typical representatives of affinity GFET sensor and metabolic GFET sensor,which were taken as examples to detect bio-interferon γ and glucose in phosphate solution(pH7.4)and in a clean room with a temperature of 25~27℃ by using a differential GFET sensor portable device.Raman spectroscopy,AFM detection and electrical detection were used to characterize PASE,aptameric and graphene before and after PBA modification.Verify the sensor’s ability to resist external interference through artificially changing the PH value and ion concentration of phosphate solution.In this paper,the detection data of interferon gamma and glucose were normalized,the differential GFET sensor response signal mathematical model was used for fitting,and verify the performance of the sensor.