| AVS 64th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology Division | Tuesday Sessions |
| Session NS+EM+MN+PS+SS-TuA |
| Session: | Nano-Photonics, Plasmonics and Mechanics |
| Presenter: | Stephane Evoy, University of Alberta, Canada |
| Authors: | W. Zheng, University of Alberta, Canada R. Du, University of Alberta and The National Institute for Nanotechnology Y. Cao, University of Alberta and The National Institute for Nanotechnology, Canada M.A. Mohammad, University of Alberta, Canada S.K. Dew, University of Alberta, Canada M.T. McDermott, University of Alberta and The National Institute for Nanotechnology S. Evoy, University of Alberta, Canada |
| Correspondent: | Click to Email |
Analysis of biological molecules is vital in many fundamental problems of molecular biology. ELISA is a widely employed array-based technique for the parallel analysis of biological analystes. This technique however requires fluorescent tagging, which may disrupt the biochemical properties being investigated. Other platforms such as quartz crystal microbalance (QCM) and surface plasmon resonance sensors (SPR) offer alternatives for the analysis of molecular mixtures. However, these platforms are not readily scalable towards large arrays. Resonant mechanical sensors operate by monitoring shifts of resonance frequencies associated to the binding. Such approach enables the frequency modulation of the output, improving the stability/noise-immunity of the reading. In addition, the adsorption sensitivity per unit area of resonators scales favourably as their dimensions are reduced, offering a compelling path for the development large arrays with exquisite mass-sensitivities.
Suspended silicon resonators as narrow as 45 nm were initially reported by Carr, Evoy et al.1 The brittle properties of this material however limited the yield of these structures to less than 25 %, precluding their use in large arrays. We have recently reinvented the overall approach employed in NEMS fabrication. This new approach combines surface and bulk machining techniques for the release of the device, as opposed to the widely-accepted sacrificial layer approach. We are now routinely fabricating ultra-large arrays of SiCN nanostring resonators as narrow as 8 nm and a yield approaching 100%. These are the narrowest devices produced by any machining method. Each device offers a detection threshold as small as 200 Da. These arrays have successfully been employed for the detection and analysis of protein mixtures. Diazonium modification was developed onto the SiCN surfaces and validated by X-ray photoelectron spectroscopy. Similarly modified nanostrings were then covalently functionalized with anti-rabbit IgG as molecular probe. Specific enumeration of rabbit IgG was successfully performed through observation of downshifts of resonant frequencies. The specificity of this enumeration was confirmed through proper negative control experiments. Helium ion microscopy further verified the successful functionalization of nanostrings.
1D. W. Carr, S. Evoy, L. Sekaric, H. G. Craighead, J. M. Parpia, App. Phys. Lett. 75, 920 (1999).