Intensity-detection-based guided-mode-resonance optofluidic biosensing system for rapid, low-cost, label-free detection

摘要

We present an intensity-detection-based optofluidic biosensing system with a disposable guided-mode-resonance (GMR) biosensor chip for low-cost, rapid, label-free biosensing. The developed sensing system consists of a low-cost spectrally limited light-emitting diode (LED) as the light source and a photodetector as the optical receiver. This detection instrument can transform the GMR wavelength shift induced by the change in the local refractive index (RI) near the chip's grating surface into change in the light intensity, thus enabling label-free, real-time detection. RI measurement experiments in both the transmission and reflection modes are performed to study the corresponding sensing mechanisms and compare detection performance. The results indicate that this sensing system operating in the reflection mode can achieve a superior RI resolution of 4.10 × 10~(-5) RIU over a wide linear detection range of 0.04 RIU. Label-free biomolecular interaction experiments show that a low limit of detection (LOD) of 7.5 × 10~(-8)g/ml for dinitro-phenyl (DNP)/anti-DNP interactions can be achieved, thus confirming the our system's sensitivity. The present investigation demonstrates a low-cost, compact, high-performance optofluidic biosensing system for rapid and sensitive biochemical detection that can be utilized for a wide variety of applications.