All-dielectric photonic nanoresonators for visible-range biosensing with cell-mimetic functionalization

Abstract All-dielectric nanophotonic sensors are emerging as powerful platforms for high-resolution, label-free detection, exploiting sharp Mie-type resonances in low-loss materials. These sensors offer key advantages over metallic counterparts, including biocompatibility, highly hydrophilic surfaces and negligible heating that preserves delicate biochemical assemblies. While most reported all-dielectric sensors operate in the infrared, where resonances are stronger, translation into the visible spectrum is highly desirable for biological sensing, offering compatibility with standard optical components and enhanced sample interaction. In this work, we present a cost-effective nanofabrication strategy for high-performance silicon-based nanoresonators operating in the visible range and integrated into compact light prism-coupling devices. Using hole-mask colloidal lithography, we reproducibly fabricate short-range ordered silicon nanodisk array sensors with refractometric resonances around 720 nm and narrow bandwidths. We demonstrate a bulk refractometric sensitivity of 543 nm per refractive index unit (nm RIU −1 ) and a detection resolution as low as 10 − 6 RIU, superior to analogous nanoplasmonic sensors. Integration of these nanosensors into a small-footprint optofluidic device allows for time-resolved analysis of biochemical interactions in a user-friendly, semi-automated format. Finally, as a proof of concept, we demonstrate their stable and efficient functionalization with supported lipid bilayers as cell membrane-mimicking interfaces for advanced on-chip studies of cell interactions or cell activity monitoring.