We have demonstrated real-time, label-free detection of small molecule binding using a novel optical biosensor. This sensor is a recently developed sensing platform incorporating a one-dimensional photonic crystal (PC) structure in a total-internal-reflection (TIR) geometry (PC-TIR). This simple configuration functions as an open Fabry-Perot resonator which provides a narrow optical resonance to enable label-free, highly sensitive detection of analyte molecules on the sensing surface in the enhanced evanescent field. Moreover, when the differential intensity modulation during binding is measured, a very high detection sensitivity can be obtained, and real-time binding observed. The well-studied biotinstreptavidin system was chosen to calibrate the detection limit for small molecule detection. Effective surface functionalization methods for streptavidin immobilization on the silica sensing surface were investigated, and analyte biotin molecules specifically binding to the sensing surface were monitored in real time. The binding of the smallest molecule D-Biotin, with a molecular weight of 244 Da, was easily experimentally observed with a high signal to noise ratio, which shows that the PC-TIR sensor has great potential to be a high-sensitivity and high-throughput sensing technology for small molecule binding analysis.

Date Published: 25 February 2010
PDF: 8 pages
Proc. SPIE 7553, Frontiers in Pathogen Detection: From Nanosensors to Systems, 755303 (25 February 2010); doi: 10.1117/12.846011

Published in SPIE Proceedings Vol. 7553:
Frontiers in Pathogen Detection: From Nanosensors to Systems
Philippe M. Fauchet; Benjamin L. Miller, Editor(s)