Microring resonator biosensing platform for sensitive detection of thrombin

Integrated-optical biosensors such as, for example, the microring resonator (MRR) and Mach-Zehnder interferometer, are more and more commercialized, mainly because of their high intrinsic sensitivity in combination with the possibilities they offer for integration in optofluidic devices. Previously, we have described the development and basic characteristics of MRR sensor chips that were fabricated in the TriPleX based silicon-nitride platform1 . In the present work, results are shown for the quantitative and sensitive detection of thrombin with aptamer-modified sensor chips. First, the modified MRR biosensor chips were tested for the binding and detection of thrombin using a repetitive number of binding/regeneration cycles on buffer sample containing 100 nM of thrombin. Then the binding curve was determined using different concentrations of thrombin, which revealed a limit of detection of 1 nM and a dynamic range up to roughly 0.5 μM of thrombin. Results from the thrombin binding experiment showed a stable performance during the course of multiple binding and regeneration cycles.