Development of a Portable Surface Plasmon Resonance Sensor with Multi-Sensing Points Based on the Linear CCD Sensor

Abstract

A portable-type surface plasmon resonance (SPR) sensor, composed from a new optical system for multi-sensing, has been developed to apply to environment analysis, clinical diagnosis etc., where many samples are desired to be analyzed at high throughput. The optical system of the sensor consists of a light-emitting diode, a pair of cylindrical lenses, a pair of collimator lenses, a correction lens, a prism, a polarizer and a linear CCD sensor with 2048 pixels. Reflected light from a sensor chip of the width of 6 mm at a certain incident angle was detected by ca. 618 pixels of the linear CCD sensor as an SPR sensor signal. An SPR sensor signal at a specified incident angle is controllable for optimization by adjusting the position of the CCD sensor. A sensor chip having a 30-stripe linear pattern (100 μm width/stripe) was prepared. The spatial resolution as well as the performance of the sensor were evaluated by using sucrose solutions. As a result, the acquisition of SPR sensor signals from 30 sensing points was successfully achieved with a spatial resolution of 100 μm (distance between 2 sensing points). A lower detection limit of ca. 3.2 − 5.5 × 10⁻⁵ RIU with a standard deviation of ±4.5% was obtained by averaging the signals from 6–7 pixels of the CCD sensor per one sensing stripe.