Interfering surface and localized plasmon: Tuning the Wood anomaly for biosensing

•Plasmon resonance pinned to a surface of sensing element provides a challenge to detect negligible concentrations of biomolecules in human fluids.•Aiming at optical sensors for the lab-on-a-chip technology, our work discusses how to get the maximum of sensitivity via tuning the Wood anomaly.•We demonstrate spectra of high quality lithography-made plasmonic 1D nanostructures.•These nanostructures are believed to be good candidates for integration into compact microfluidic devices for SPR-based biosensing. We demonstrate spectra of slabs of plasmonic 1D nanostructures and show their changes when detecting specific biomolecular binding. The slabs were fabricated by electron-beam lithography, they had sub-millimeter dimensions and allowed us to detect a specific binding of low-density lipoproteins. Optical spectra of the slabs exhibiting a spectrally sharp resonant peak have been analyzed numerically to interpret their features and to define structural parameters governing the quality factor of the resonance. We show a comparison between the sensing performances of the different slabs under study, thus discussing their better designs and experimental geometries.