Customized High-Sensitivity Plasmonic Metasensing Towards Immunodetection of Single Bio-Nanoparticles

Plasmonic metasurface biosensing has shown great potential in label-free detection of bio-nanoparticles with various sizes, such as cancer antigens, exosomes and SARS-CoV-2 virus. It typically relies on the immunoassay, but current studies usually neglect the perfect size matching between each target bio-nanoparticle and the surface near-field domain, which should be very critical for the enhancement of detection performance. In order to maximize the immunodetection capability for each bio-nanoparticle, we propose a plasmonic meta-biosensor based on the field-customized mechanism. Our design overcomes the serious interference of biofunctionalization and accomplishes a sensitivity of 27 times higher than the conventional nanoplasmonic counterpart. Our method also builds the important basis of single bio-nanoparticle immunodetection by a plasmonic metasurface. The customized plasmonic metasensing study implies a promising way towards ultra-low concentration biosensing or even single bio-nanoparticle detection for high-performance point-of-care-testing in the near future.