Electrolyte-gated IGZO Thin-film Transistors For Anti-TB Drug Screening And M.tb Sensing

Recently,amorphous indium gallium zinc oxide(a-IGZO)-based thin film transistors(TFTs)have been widely used in the field of biological detection due to their superior features such as high electrical mobility,low-preparation temperature,strong chemical stability and good biocompatibility.Compared with traditional IGZO TFTs,electrolyte-gated IGZO TFTs can operate stably in aqueous environment with relatively low working voltages(?1 V),which are more suitable to development of a real-time monitoring anti-tuberculosis(anti-TB)drug screening test platform and highly sensitive Mycobacterium tuberculosis(M.tb)detection technology.In this thesis,we mainly focus on the following three parts:(1)preparation and optimization of electrolyte-gated IGZO TFTs;(2)electrolyte-gated IGZO TFTs-based biosensor for macrophage sensing and anti-TB drug screening;(3)construction of photo-electrolyte-gated IGZO TFTs-based biosensor and its use for highly sensitive M.tb detection.Firstly,the effects of different a-IGZO film preparation methods on the electrical properties and stability of the electrolyte-gated IGZO TFTs were investigated.The results showed the devices fabricated by magnetron sputtering and pulsed laser deposition both have a good electrical property and stability.And then the magnetron sputtering method was used in our research for preparation of the electrolyte-gated IGZO TFTs,because of its advantages such as strong practicability,large-area deposition and so on.The process conditons of argon-oxygen ratio and annealing temperature were optimized with an optimal value of 60:6 and 350?,respectively.The channel current of the devices prepared by magnetron sputtering could vary by 5?6orders of magnitude when the gate voltage varied of within 1 V,and the devices could keep stable within 7 days in PBS solution.Secondly,the real-time monitoring growing process of macrophage by electrolyte-gated IGZO TFTs was studied.The results showed that with the growth and proliferation of macrophages,the?V_GS-T curve of the devices kept rising firstly,and followed by a stationary stage.After 48 hours,there was a shift of transfer curve(?V_GS)about 120 m V.In addition,using the electrolyte-gated IGZO TFTs,we monitored the interaction between macrophages infected with M.tb and anti-TB drugs.We found that a slowly upward trend appeared after 48 hours in the?V_GS-T curve with 100?g/m L of rifampicin treatment,which indicated that the rifampicin at this concentration has a remarkable antibacterial effect on intracellular M.tb,resulting in a recovery of the celluar activity in some macrophages.Therefore,the electrolyte-gated IGZO TFTs can be used as a platform for drug susceptibility tests.By designing array structure,rapid and high-throughput screening of anti-TB drugs can be achieved.Finally,a photo-electrolyte-gated IGZO TFTs was successfully constructed by combining the electrolyte-gated IGZO TFTs with photoelectrochemical(PEC)bioanalysis,and achieved a highly sensitive detection of M.tb.Furthermore,the working principle of the photo-electrolyte-gated IGZO TFTs was explored.It was found that under a certain wavelength photoexcitation,the photoactive materials Cd S quantum dots(Cd S QDs)on the gate electrode undergone an electron transition accompanied with a simultaneous charge transfer,causing the potential at the gate/electrolyte interface of device to change.As a result,the channel current of device changed under the effective gate voltage changing.The photo-electrolyte-gated IGZO TFTs-based biosensor was studied for high-sensitively detecting M.tb.The results showed that the optimal performance of the device could be achieved when the aptamer concentration and incubation time were 5?M and 2 hours,respectively.The M.tb biosensor had a linear detection range from 50 to 10⁸ cells/m L,with a detection limit of 50 cells/m L.Moreover,the device had a good selectivity to M.tb.And the sensing mechanism could be attributed to the hindrance effect of M.tb to the charge transfer on the gate electrode.We believe that electrolyte-gated IGZO TFTs-based biosensor array is very suitable for rapid and high-throughput screening of anti-TB drugs and will help accelerate the development of new drugs.In addition,the photo-electrolyte-gated IGZO TFTs-based biosensor can be highly sensitive to detect M.tb,which is beneficial to the early discovery TB,so as to the effective control of infection.