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

Abstract

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.

Hottest Hotspots from the Coldest Cold: Welcome to Nano 4.0

“…These attributes of enhanced longitudinal modes and anisotropy in the structures contributes significantly to the scattering cross section of the nanostructures (and less toward the absorption cross section). ,, Consequently, such nanomaterials are considered ideal for MEF and SPCE applications. − Further, the hydrodynamic radius displayed an increasing trend for increasing time of adiabatic cooling (Figure b). This indicates that a higher number of NPs constitutes the nanoassembly with an increase in time.…”

“…The hexagonal array of bright diffraction spots observed in the selected area electron diffraction (SAED) study (Figure 5e and f) provides strong evidence for the graphene-like honeycomb structure. 3,15,26,27,40 The SAED taken in the nanojunction between the AgNP and GO belonging to a single AgGOCS is shown in Figure 5e. Here, we observed the diffraction bright spots corresponding to that of Ag (with d-spacing and Miller indices given in white) in the dim background of the 6-fold array of bright spots corresponding to GO.…”

“…The line profile study indicates a relatively lower intensity of the outer ring [2110-type (blue)] as compared to that of the inner ring [1100-type (yellow)] (given in Miller− Bravais hkil notation), thereby confirming the monolayer attribute of GO, in accordance with earlier works. 3,15,26,27,40 All of the samples were studied in spacer, cavity, and extended cavity nanointerfaces, and the results are presented in Figure 5h. We observe that AgNPs, GO, and AgGOCS presented different trends in the SPCE enhancements.…”

Sericin-Based Bio-Inspired Nano-Engineering of Heterometallic AgAu Nanocubes for Attomolar Mefenamic Acid Sensing in the Mobile Phone-Based Surface Plasmon-Coupled Interface

“…In this background, it is imperative to specify the futuristic opportunities with the development of mobile phone-based detection systems, from the plasmonics-based biosensors perspective. Conventional photo-plasmonic biosensors are developed with the use of nanotechnology, wherein the nanomaterials or nano-antennas are specifically designed to understand the physicochemical demands or target optical property/design. − Theoretical and simulation-based analyses are extensively performed to comprehend the expected light–matter interactions, and accordingly, the experimental protocols are designed. These analyses are generally carried out with the use of numerical equations, solving the Maxwell equation under appropriate boundary conditions.…”

“…The property of the evanescent wave generated in the surface plasmon-coupled emission (SPCE) platform has been effectively modulated with different nano-engineering strategies in the past decade. Nanomaterials sustaining metal plasmons (Ag, Au, Pt), , dielectric plasmons (Nd 2 O 3 , TiC, TiN, TiCN), − magnetic plasmons, and graphene Dirac fermions and other 2D material plasmons − have been evaluated in the SPCE platform to comprehend insightful attributes of light–matter interactions such as Rabi splitting, Fabry–Perot photonic mode coupling, Casimir force, Fano resonance, quantum confinement, and Purcell effect. ,, Consequently, the aforementioned strategies aim at augmenting electromagnetic (EM) field intensity at the nanogaps between plasmonic nanomaterials and the metal thin film, which are termed as “hotspots” that are essentially utilized for demonstrating novel biosensing frameworks.…”