An integrated micromanipulation and biosensing platform built in glass-based LTPS TFT technology

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.