Microfluidic-Free Surface Plasmonic Lattice Resonance Fiber Probe Enabled Portable Molecular Interaction Sensing

Balancing high sensitivity and detection efficiency is a key challenge in plasmonic molecular sensing. We report a portable surface plasmonic lattice resonance (SLR) optical fiber probe integrating a non-close-packed gold nanoparticle array on the fiber endface. Its coaxial optical design allows direct immersion in liquids, removing complex microfluidics and boosting efficiency. The high refractive-index sensitivity of SLRs enables the sensitive monitoring of molecular interactions. DNA hybridization experiments show a detection limit of 10 nM. This work establishes a practical strategy for integrating high-performance plasmonic nanostructures with optical fiber platforms and provides a promising route toward high-sensitivity portable biochemical sensors.