Photoluminescent molecule-boosted metasurface plasmon resonance via nonradiative energy transfer

Surface plasmon resonance (SPR) technology has become a powerful tool for studying molecular interactions due to its label-free, real-time detection capabilities. However, the sensitivity limitations of conventional SPR have restricted its broader application. In response to this challenge, our study introduces an optical optimization, the photoluminescent-boosted Metasurface plasmon resonance (PLMLMSPR), which integrates photoluminescent molecule materials with a multilayer metal-enhanced metasurface plasmon resonance (MLM-MetaSPR) chip. Building upon the optimization of the nanocup array structure and multilayer metal composition, the metasurface chip is modified with a three-dimensional scaffold of carboxymethyl chitosan via carbene photopolymerization, further enhancing both protein immobilization and sensor sensitivity. Leveraging the metasurface chip, the photoluminescent molecule is labeled onto the antibody for signal amplification through a sandwich immunoassay system, achieving the ultra-sensitive PLMLMSPR platform. The incorporation of photoluminescent materials successfully harnessed nonradiative energy transfer to augment the local free electric field through enhanced transmission by absorbance of a photon, thereby significantly enhancing the plasmonic resonance effect in MetaSPR technology. This approach has doubled the sensor's response signal and improved the detection limit fourfold while maintaining protein-ligand affinity, as demonstrated by the effective detection of both SARS-CoV-2 wild-type and emerging variants, highlighting its remarkable practicality in diagnostic applications.