Reagentless Optical Biosensor

摘要

Critical to our ability to respond effectively to a biothreat attack is the development of sensitive and specific sensor systems that can easily be used for rapid screening of potential victims for infection due to biothreat agents and detection of pathogens in the environment. To help address these needs, we have developed a Reagentless Optical Biosensor (ROB) based on protein specific assays and waveguide-based evanescent fluorescence excitation. Modeled on host pathogen interactions, the sensor's membrane based assay provides rapid, sensitive detection without the addition of reagents. We report here the development of two waveguide based detection systems: a laboratory sensor test-bed system and a handheld, battery operated, prototype. Evanescent fluorescence excitation using planar optical waveguides provides spatial filtering of background auto-fluorescence found in many natural samples, thereby permitting direct analysis of complex environmental and medical samples. The waveguide based assay is fully self-contained in a small, exchangeable cartridge that is optically coupled to the sensor detection system making ROB simple to use and offering the possibility of inexpensive, disposable sensor elements. Using assays for cholera toxin we compare results using flourimetry of vesicle solutions against results for our waveguide based test-bed and prototype sensor systems.