Mobile Phone Camera-Based Detection of Surface Plasmon-Coupled Fluorescence from Streptavidin Magnetic Nanoparticles and Graphene Oxide Hybrid Nanointerface

Surface plasmon-coupled fluorescence (SPCF) technique has developed as a highly sensitive, specific, and versatile methodology for quantitative and qualitative bioassays. It relies on the ability of prism-coupling approach to channelize the emitted photons into sharply directional emission with attributes of propagating surface plasmons resulting in highly p-polarized emission. There are voluminous research studies demonstrating the utility of wide range of nanomaterials as effective spacers in SPCF. Streptavidin magnetic nanoparticles (SMNPs) serve as excellent candidates for biomedical applications on account of their biocompatibility and tunable magnetic properties. From the perspective of magneto-plasmonics, although they are excellent candidates for SPCF explorations, they are underutilized in this domain. In this background, we report the first-time demonstration of quintessential integration of SMNPs and graphene oxide π-plasmons as crucial spacer material for augmented SPCF. The results obtained with exorbitant detector systems are substituted with reliable mobile phone camera based detectors, amenable for resource-limited settings.