  Plasmonic surface lattice resonance (SLR) is a phenomenon in which individual
localized surface plasmon resonances (LSPRs) excited in periodically-arranged
plasmonic nanoparticles couple through the interaction with propagating
diffracted incident light. The SLR optical absorption peak is by at least one
order of magnitude more intense than the LSPR one, making SLR superior for
applications in which LSPR is commonly used. Recently, we have developed a
route for the fabrication of spherical virus-like particles (VLPs) with
plasmonic cores and protein coronas, where the LSPR in the cores amplifies
vibrational signals originating from protein-antibody bonding, showing the
potential of VLPs in biodetection. However, the signals were not strong enough
to detect antibodies at very low concentrations. Here, we show that by ordering
the VLPs in periodic nanoarrays exhibiting SLR amplifies the signals by two
orders of magnitude, revealing superior potential of SLR arrays in
ultrasensitive biodetection.
