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The glass-based low-temperature polycrystalline-silicon (LTPS) thin-film transistor (TFT) process, as widely known for making liquid crystal displays, is utilized in this work to realize a fully integrated, microbead-based micro-manipulation and biosensing platform. The operation utilizes arrays of microelectrodes made of transparent iridium tin oxide (ITO) to move the immobilized polystyrene microbeads to sensor surface by dielectrophoresis (DEP). Detection of remaining microbeads after specific antigen/antibody reaction is accomplished by photo-detectors under the transparent electrodes. It was found that microbeads can be driven successfully by the 30×30 μm2 microelectrodes separated by 10 μm with no more than 6 V p-p , which is compatible with the operating range of thin-film transistors. Microbeads immobilized with anti-mouse immunoglobulin (IgG) antibody were successfully detected after specific binding, illustrating the potential of LTPS TFT microarrays for more versatile biosensing applications.

The glass-based LTPS (low temperature polysilicon) TFT (thin-film transistor) process, as widely known for making liquid crystal displays, is utilized for the first time to make CMOS capacitive sensors for dopamine detection. Dopamine plays important roles in human behavior, cognition, and motor activity. The interface capacitance change, after its binding with 4-carboxyphenylboronic acid (CPBA), was detected by interdigitated microelectrodes and integrated sensing circuits. Three sensor designs showed measured sensitivities of −3.9 fF/mM, −5.4 fF/mM, and −7.2 fF/mM, respectively. The minimum detectable capacitance changes were 12.7 aF, 14.7 aF, and 13.5 aF, equivalent to detectable dopamine concentrations of 3.2 µM, 2.7 µM, and 1.9 µM, respectively.

The glass-based low-temperature polycrystalline-silicon (LTPS) thin-film transistor (TFT) process, widely known for making liquid crystal displays, is utilized in this work to realize a fully integrated, microbead-based micro-manipulation and biosensing platform. The operation utilizes arrays of microelectrodes made of transparent iridium tin oxide (ITO) to move the immobilized polystyrene microbeads to the sensor surface by dielectrophoresis (DEP). Detection of remaining microbeads after a specific antigen/antibody reaction is accomplished by photo-detectors under the transparent electrodes. It was found that microbeads can be driven successfully by the 30???30??m2?microelectrodes separated by 10??m with no more than 6?Vp?p, which is compatible with the operating range of thin-film transistors. Microbeads immobilized with antimouse immunoglobulin (IgG) and prostate-specific antigen (PSA) antibody were successfully detected after specific binding, illustrating the potential of LTPS TFT microarrays for more versatile biosensing applications.