Quartz-on-Silicon Microacoustic Multiplexed Biosensor for In Vitro Label-Free Medical Diagnosis

Advanced biomedical analyses require simultaneous quantification of multiple entities (cells, proteins, viruses, vesicles, …) calling for a multiplexed and compact biosensor. Label-free approaches giving access to the kinetic of interaction between key molecules are solid candidates for these analyses, but they currently lack either robustness for field use, multiplexing ability, or specificity. In this contribution, we report on the development of a new type of device that merges advantages of microsystem-based integrated solutions and performance of quartz acoustic wave biosensors. We have fabricated an acoustic wave biosensor composed of multiple independent detection units, each equipped with a specific surface biointerface for the selective detection and quantification of target analytes. The implementation of reflector structures on each sensing unit enables effective wave confinement, allowing for multiplexed measurements without compromising the performance of individual units. This technology relies on commercially available quartz and silicon wafers. To demonstrate the usefulness of our approach, we developed a proof-of-concept biosensor for the assessment of primary hemostasis. This assessment is based on monitoring the adhesion of platelets on functionalized surfaces during the sequence of events that leads to primary hemostasis. The biosensor directly takes whole blood and allows real-time measurement of resonance frequency and dissipation factor of 3 sensing units placed in a row. We have then characterized the specificity, repeatability, cross-talk, and sensitivity and estimated the resolution of the multiplexed biosensor. Finally, the device allowed detecting a simulated primary hemostasis defect using a modified blood sample. This proposed bioassay technology offers strong potential for broad applications in biomedical studies as an improved alternative to quartz crystal microbalance-based devices for multiplexed biointeraction analysis.