MOFs-based Field Effect Transistor Biosensor And Their Eletrical And Sensing Performance

The detection of bioactive molecules is of great significance in environmental monitoring,biological research and medical testing.The field effect transistor biosensor is a new type of detection device that can convert biological signals into electrical signals for detection,because it has the advantages of fast response,real-time detection and high sensitivity,which makes it possess important value in the field of biological detection and research.MOFs materials have the characteristics of high specific surface area,rich active sites,and adjustable pore structure.They are one of the ideal choices for field effect transistor channel layer materials.Research and preparation of MOFs-based field effect transistors as electrochemical biosensors can expand the application of field effect transistors in the field of biological detection,and combine the advantages of MOFs materials and field effect transistors to develop new and high-performance biosensor devices.Based on the above discussion,the main research contents and results obtained are as follows:1.A simple,in-situ growth method based on solid-liquid interface reactions was used to prepare a Ni-MOFs-FET device with a large area,uniform,and controllable thin film structure.As the reaction time is appropriately extended(less than 120 minutes),the conductivity and field-effect performance of the field-effect transistor are improved,thereby realizing the regulation of the electrical performance by changing the reaction time.Compared with devices prepared by other methods(stamping method,drop coating method and blend spin coating method),the optimized Ni-MOFs-FET device has high carrier mobility of 45.4 cm2 V-1s-1 and good current switching ratio of 2.29×103.However,a method of spin coating with a certain concentration of chitosan and Ni-MOFs powder can produce a uniform film,and the thickness and conductivity of the film can be adjusted by spin coating.Therefore,this method can be further studied in subsequent studies.In addition,the Ni-MOFs-FET device can be used as a liquid-gated field-effect transistor,which has better stability in solution testing,and has a good response to gluconic acid in the range of 10-6 g/mL to 10-3 g/mL,showing its potential applications in the field of biosensors.2.A bimetallic Ni/Cu-MOFs thin film with good film formation properties is prepared by the in-situ reaction of mixed metal solution and HATP organic ligand on a field effect transistor,wherein the Ni ion and Cu ion input in the reaction are adjusted.The Ni/Cu-MOFs(7:1)-FET prepared when the molar ratio is 7:1 has good field effect performance.X-ray photoelectron spectroscopy analysis shows that Ni ions and Cu ions in bimetal MOFs have a synergistic effect,which is also the main reason for the increased conductivity and field effect performance of Ni/Cu-MOFs(7:1)-FET compared to single metal Ni-MOFs-FET and Cu-MOFs-FET.Ni/Cu-MOFs(7:1)-FET was modified with glutaraldehyde and glucose oxidase to obtain GOD-GA-Ni/Cu-MOFs(7:1)-FET enzyme sensor device,which is used as a liquid gated device in PBS solution.The transconductance(gm)during the test in the buffer solution was 20.47 ?S,the carrier mobility(?)was 401.05 cm2 V-1,s-1,the current switching ratio(Ion/Ioff)was 4.89,and the threshold voltage(Vth)was 0.32 V.GOD-GA-Ni/Cu-MOFs(7:1)-FET enzyme sensor has good detection performance for glucose through enzymatic reaction,and it has a wide detection range of 1?M to 20 mM:In the low concentration range(1?100?M)has a higher sensitivity of 26.05?A cm-2 mM-1:when tested at the higher concentration(100?M?20mM),its sensitivity reaches 10.96 ?A cm-2 mM-1,and it can achieve lower detection limit of 0.51?M.The enzyme sensor has the advantages of good specificity,reproducibility,short-term stability,and short response time in the application of glucose detection,so it is expected to be a biosensor for real-time detection of glucose in the future.