New microphotonic resonant devices for label-free biosensing

In the last few years, the interest towards chip-scale microphotonic resonant label-free biosensor is quickly growing. In this context, novel low-cost platforms able to simultaneously detect, with high resolution, several target molecules in an ultra-small volume of biologic fluid are strongly demanded. In this paper, the recent advances in the field of resonant microphotonic platforms for label-free biosensing are critically reviewed, with a special emphasis on the devices exhibiting an ultra-high sensitivity due to a strong light-matter interaction. A new multi-analyte biosensing platform in silicon nitride technology is reported. The platform is based on a properly designed configuration of planar ring resonator and exhibits a record limit-of-detection of 0.06 pg/mm2. The applications of the platform in the field of medical diagnostics and environmental monitoring are discussed.