Fabrication and Characterization of an Aptamer-Based N-type Silicon Nanowire FET Biosensor for VEGF Detection

Abstract

Cancer detection is an important part of modern medical diagnosis and many strategies based on nanotechnology had been developed in recent years. Of which, silicon nanowire (SiNW) field-effect transistor (FET) biosensor via DNA aptamer capture is considered as an interesting and viable option. Hence, in this report, we had assembled a n-type triple SiNW FET biosensor for the detection of vascular endothelial growth factor (VEGF) via surface functionalized DNA aptamer for a proof-of-concept. The SiNW FET biosensor was fabricated via "top-down" approach and the physical nature of the nanowire assembly was examined via atomic force microscopy (AFM) as well as scanning electron microscopy (SEM). We had subsequently grafted VEGF specific DNA aptamer via conventional EDC/NHS chemistry and later measured the conductance of the nanowires in a four-point probe detector for VEGF detection. We had demonstrated that the detection of VEGF was possible even at a concentration of 2.59 nM which was highly comparable to the other common biosensors for detection of VEGF protein. In addition to being scalable with complementary metal–oxide–semiconductor (CMOS) technology, the findings as demonstrated from our simple SiNW FET biosensor setup had helped to provide better insights towards optimizing the approach for the development of the next generation of miniature biosensors.