Title: Development of real-time and label-free Immunoassay Chips by Using IGZO(Indium Gallium Zinc Oxide)-TFT(Thin Film Transistor)-based biosensors

Biography:

Dongchen Zhu has completed his bachelor at the age of 22 years from Shanghai Jiaotong University, China and currently he is pursuing master studies from Department of chemical system engineering, Tokyo University, Japan.       

Abstract

Thin film transistor (TFT) technology has been widely utilized in display, but seldomly been used in biosensing in spite of its priority in relatively high electron-mobility, economic-friendly manufacturing and lower energy consumption. Here we immobilized anti-human albumin (anti-HAlb) and examined to directly detect human serum albumin (HSAlb) molecules at the surface of an IGZO (Indium Gallium Zinc Oxide)-TFT array with 400 transistors densely from impedance measurements[]. DC and AC voltages were applied on the neighboring two gates and sources, respectively. After the recognition of HSAlb by anti-HAlb, the output current at 1000Hz increased in a pH 7.4 phosphate buffer solution (PBS) due to changes in electrostatic capacitance and ion mobility at the ITO (Indium Tin Oxide) surfaces as shown in Fig. 1. We also successfully observed the output current response even at the low level of 20 ng/ml for albumin molecules. Furthermore, higher diluted PBS demonstrates larger magnitude of output signals after antibody-antigen reactions, as shown in Fig. 2, probably due to lower ionic strength. The other reason could be pH value of higher diluted PBS is much closer to the isoelectric point of albumin and its antibody, where both of them are approximately of electrical neutrality. In the future, the present IGZO-TFT biosensors are promising for a label-free multiple immunoassay method.