Optical biosensor based on hollow integrated waveguides

摘要

The first absorbance biosensor based on pure silicon hollow integrated waveguides. is presented in this work. With the use of horseradish peroxidase (HRP) as a model recognition element, an enzymatic sensor for the measurement of hydrogen peroxide was fabricated, numericaflysitnulated,and experimentally characterized. Waveguides with widths ranging from 50 to 80 mu m, having a depth of 50 mu m and lengths up to 5 mm were easily fabricated by just one photolithographic step. These were further modified by covalent immobilization of HRP using silanization chemistry. Simulation studies of the proposed approach showed a sensor linear behavior up to 300 mu M H2O2 and a sensitivity of 2.7 x 10(-3) AU/mu M. Experimental results were in good agreement with the simulated ones. A linear behavior between 10 and 300 mu M H2O2, a sensitivity of 3 x 10(-3) AU/mu M, and a signal-to-noise ratio around 20 dB were, attained. Also, kinetic studies of the activity of the immobilized enzyme on the silicon waveguide surface gave an apparent Michaelis-Menten constant of 0.44 mM. The simple technology proposed in this work enables the fabrication of cost-effective, easy-to-use, miniaturized biosensor generic platforms, these being envisioned as excellent candidates for the development of lab-on-a-chip systems.