FEASIBILITY OF OPTICAL WAVE-GUIDE IMMUNOSENSORS FOR PESTICIDE DETECTION - PHYSICAL ASPECTS

The feasibility of detecting small molecules such as pesticides using optical evanescent-wave sensors is discussed with emphasis on the Mach-Zehnder sensor and a newly developed sensor called a 'critical' sensor. For direct detection of an estimated average pesticide layer growth of 2X10(-4) nm, the sensitivity of the Mach-Zehnder sensor is almost adequate (1X10(-3) nm within one hour), whereas that of the 'critical' sensor (2X10(-2) nm) is not sufficient. However, the simplicity of this latter sensor is very attractive. Results of alpha-hSA/hSA immunoreaction experiments obtained with this last type of sensor are presented.