A. Radadia, N. Privorotskaya, E. Corbin, R. Bashir, Bill King; University of Illinois, Urbana-Champaign
This is a joint project between Advanced Diamond Technologies Inc. (ADT), Center for Nanoscale Materials (ANL), the University of Wisconsin-Madison (UW), and the University of Illinois. The aim of this project is to develop sensitive, robust diamond microcantilever-based biosensors for real-time detection of water-borne bacterial pathogens, with intial testing to be done using E. coli O157:H7.
Figure 1a shows an atomic force microscope image of the ultra nano crystalline diamond (UNCD) surface as deposited by ADT. UNCD is a special diamond thin film that can be deposited on silicon wafer and patterned using standard cleanroom processes. UNCD microcantilever structures like the one shown in figure 1b (20 x 8 x 2 micron) have been fabricated in Prof. King and Bashir’s group at Illinois. Also previous reports (shown in figure 1c) from Prof. Hamers’ group show that surface chemistry on diamond is highly stable to temperature cycling and is advantageous for carrying out multiple DNA hybridization and dehybridization cycles. Current work focuses on evaluating the functional and structural stability of immunoglobulins when tethered to UNCD surface under sensor operation conditions. Figure 1d and 1e show green fluorescence and SEM images of E.coli O157:H7 captured on anti-O157:H7 functionalized UNCD surface. Figure 1f shows capture of fluorescently labeled E.coli O157:H7 on UNCD microcantilevers (120 microns x 80 microns x 2 micron). Upcoming work will involve system integration aspects including biofunctionalization of UNCD microstructures, microfluidics, and device testing for bacterial capture.