Improvement for sensitivity of biosensor with total internal reflection imaging ellipsometry (TIRIE)

The biosensor based on the total internal reflection imaging ellipsometry (TIRIE) is realized as an automatic analysis method for protein interaction processes in real-time, with high throughput and label-free. An evanescent wave is used as the optical probe to monitor bio-molecular interactions on a chip surface with a high sensitivity due to its phase sensitive property. In this paper, the technique is optimized with a polarization setting, a spectroscopic light source and a low noise CCD detector to improve the performance of the biosensor in sensitivity and detection limit, as evidenced by a quantitative detection of Hepatitis B virus surface antigen (HbsAg) with concentrations of 8, 16, 32, 64, 125 and 250 ng/ml. The sensitivity is increased by one order of magnitude and the detection limit has been extended more than 50 times for HbsAg detection.