High Sensitive Optical Detection of Bio-Chemicals onto a Silicon Oxide Surface Based on Waveguide Mode
- PDF / 1,459,433 Bytes
- 6 Pages / 595 x 842 pts (A4) Page_size
- 15 Downloads / 257 Views
0900-O12-39.1
High Sensitive Optical Detection of Bio-Chemicals onto a Silicon Oxide Surface Based on Waveguide Mode Nobuko Fukuda, Makoto Fujimaki1, Koichi Awazu1, Kaoru Tamada2 and Kiyoshi Yase Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Higashi 1-1-1, Tsukuba 305-8565, Japan 1
Center for Applied Near-Field Optics Research, National Institute of Advanced Industrial
Science and Technology (AIST), Higashi 1-1-1, Tsukuba 305-8565, Japan 2
Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Nagatsuda-cho 4259, Midori-ku, Yokohama 226-8502, Japan ABSTRACT This work presents high sensitive detection of specific adsorption of proteins onto a silicon oxide (SiOx) surface modified by molecules with a biotinyl-end group. We fabricated a SiOx waveguide by sputtering onto a thin gold film and measured the incident angle-dependence of reflectivity using a polarized He-Ne laser under total internal reflection condition. When the s-polarized light was irradiated to the SiOx waveguide (760 nm) coupled with a prism, the incident angle-dependence of reflectivity showed narrow dips due to excitation of the waveguide mode. The waveguide surface was modified by the molecules with the biotinyl-end group as a protein probe. Specific adsorption of streptavidin in a PBS buffer solution was monitored through time course of the reflectivity change at a constant incident angle, where the waveguide mode was excited. As compared with conventional SPR system using a gold surface, high sensitive detection of the specific adsorption was achieved. Additionally, we fabricated micro-patterned arrays of biotinyl-end layers onto the SiOx waveguide surface by micro-contact printing (µCP). Then we observed the specific adsorption behavior on the micro-patterned arrays by the imaging based on the waveguide mode using a CCD camera. INTRODUCTION In design of bio-sensing devices, fabrication of suitable interface for sensing methods and chemicals such as probes and analytes is one of the most important steps. The advantages of a silicon oxide (SiOx) surface as a biosensing interface are inertness to bio-chemicals and ease of surface modification using silane coupling agents. The SiOx is also a useful dielectric material as
0900-O12-39.2
a waveguide. The waveguide mode is excited by incidence of the p- or s- polarized light under total internal reflection condition. The optical setup for surface plasmon resonance (SPR), which has been widely used for a powerful bio-sensing tool [1], is available for excitation of the waveguide mode [2-4]. In this work, we fabricated a SiOx waveguide surface and investigated the sensitivity for bio-sensing based on the waveguide mode. Moreover, we fabricated the micro-patterned arrays of protein probes onto the SiOx waveguide surface by µCP [5,6] and observed the specific adsorption behavior of proteins by an imaging technique [7] based on the waveguide mode. EXPERIMENTAL DETAILS A hig
Data Loading...
