Label-Free Biosensor Arrays Based on Silicon Ring Resonators and High-Speed Optical Scanning Instrumentation

A platform for performing rapid, real-time binding assays on sensor arrays based on silicon ring resonators is presented in this paper. An array of 32 sensors is interrogated simultaneously. Using eight sensors as controls, 24 simultaneous binding curves are produced. The bulk refractive index sensitivity of the system was demonstrated down to 7.6 × 10^-7 and sensor-to-sensor variability is 3.9%. Using an 8-min incubation, real-time binding was observed over 8-logs of concentration down to 60 fM using immobilized biotin to capture streptavidin diluted in bovine serum albumin solution. Multiplexing in complex media is demonstrated with two DNA oligonucleotide probes. Time to result and repeatability are demonstrated to be adequate for clinical applications.