Surface Functionalized Graphene Biosensor on Sapphire for Cancer Cell Detection

Graphene has several unique physical, optical and electrical properties such as a two-dimensional (2D) planar structure, high optical transparency and high carrier mobility at room temperature. These make graphene interesting for electrical biosensing. Using a catalyst-free chemical vapor deposition (CVD) method, graphene film is grown on a sapphire substrate. There is a single or a few sheets as confirmed by Raman spectroscopy and atomic force microscopy (AFM). Electrical graphene biosensors are fabricated to detect large-sized biological analytes such as cancer cells. Human colorectal carcinoma cells are sensed by the resistance change of an active bio-functionalized graphene device as the cells are captured by the immobilized antibody surface. The functionalized sensors show an increase in resistance as large as similar to 20% of the baseline with a small number of adhered cells. This study suggests that the bio-functionalized electrical graphene sensors on sapphire, which is a highly transparent material, can potentially detect circulating tumor cells (CTCs) and monitor cellular electrical behavior while being compatible with fluorescence-based optical detection bioassays.We acknowledge support for this research from the AFOSR MURI FA9550-09-1-0705 and from Cornell Center for Materials Research (CCMR: DMR-1120296). This work was performed in part at the Cornell NanoScale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the National Science Foundation. We would like to thank Pengcheng Bu, Joyce Chen and Nikolai Rakhilin for helpful suggestions and discussions