Ultrasensitive detection of adipocytokines with CMOS : compatible silicon nanowire array
Tou, Zhi Qiang.
Date of Issue2009
School of Chemical and Biomedical Engineering
Silicon nanowire (SiNW) configured as field-effect transistor (FET) has emerged as a promising biosensor for quantification of molecules at low concentration levels pivotal in many areas including molecular biology research, early medical diagnosis, drug screening, etc. This project outlines large scale, high throughput fabrication of such SiNW array with well defined dimensions and reproducibility using standard complementary metal-oxide-semiconductor (CMOS) compatible techniques and demonstrates its capability for parallel detection of two adipocytokines: leptin and resistin. The sensor adopts a simple, label free electrical sensing approach to realize highly specific, ultrasensitive detection in the picomolar region with conductance change of the functionalized SiNWs logarithmically proportional to adipocytokine concentration over four orders of magnitude. The SiNW array was applied to secretion studies of 3T3-L1 fibroblast derived adipocytes. It was found that the adipocytes constitutively secrete leptin and resistin, presumably to maintain a basal serum level in the body. In the presence of glucose, pyruvate and insulin (GPI) stimulation, leptin secretion increased 3.14 folds while resistin secretion decreased 5.23 folds. Kinetics of secretion of both adipocytokines appear unchanged by GPI stimulation. These data corresponds well with literature and the device can be used to unravel the poorly understood secretion mechanism of adipocytokines, the pathways with which they exert their influence and their implications in diseases like obesity and diabetes.
Final Year Project (FYP)
Nanyang Technological University