Surface Plasmon Resonance Imaging in Nanoparticle Detection

Surface plasmon resonance imaging (SPRI) is a label-free optical technique that exploits the sensitivity of surface plasmons—collective oscillations of electrons at a metal–dielectric interface—to changes in the local refractive index. When a nanoparticle binds or resides in close proximity to the metal film, it perturbs the evanescent field of the surface plasmon polariton, producing a distinctive plasmonic image. By monitoring reflectivity or scattering intensity across an extended field of view, SPRI can detect and characterise individual nanoparticles in real time, with typical size sensitivity down to tens of nanometres. Variations in particle composition, size, shape and binding kinetics can be inferred from the spatial and temporal profiles of the plasmonic signal. Instrumental implementations range from prism-coupled Kretschmann configurations to objective-based high-numerical-aperture systems, often augmented with interferometric or dark-field contrast. Recent advances have improved spatial resolution through azimuthal modulation and optimised prism geometries, while computational models now enable quantitative interpretation of complex plasmonic images. The global impact of SPRI in nanoparticle detection spans environmental monitoring, nanomedicine, catalysis studies and point-of-care diagnostics, offering rapid, multiplexed analysis without fluorescent labels or secondary reagents.

Research from Nature Portfolio

Recent studies have introduced azimuth-modulated plasmonic scattering interferometry to achieve high-resolution imaging of single silver nanowires during electrochemical reactions. By modulating the incidence angle and suppressing interference artefacts, the approach delivers a dramatic enhancement in spatial resolution—beyond conventional limits—and reveals heterogeneous surface chemistry at the nanoscale. This technique demonstrates the potential to track dynamic interfacial processes on individual nanoparticles, offering a general strategy for real-time plasmonic imaging of nanomaterial transformations under ambient conditions.

Research from all publishers

An analytical model for plasmonic image formation has been developed to describe the electromagnetic interaction between sub-wavelength nanoparticles and surface plasmons, providing predictive insight into how particle size and chemical composition influence the plasmonic signature. Complementary work has addressed the optimisation of spatial resolution in prism-based SPR microscopy, showing that geometrical aberrations of the coupling prism can supersede plasmon propagation length as the principal limiting factor, and demonstrating diffraction-limited lateral imaging by tailored prism configurations.

Surface Plasmon Resonance Imaging in Nanoparticle Detection publication trend

The graph below shows the total number of articles in surface plasmon resonance imaging in nanoparticle detection across all publications each year (not limited to Nature Index journals).

Technical terms

Surface plasmon polariton (SPP): A surface-confined electromagnetic wave arising from the coupling of light to collective electron oscillations at a metal–dielectric interface.

Evanescent wave: An exponentially decaying electromagnetic field extending from the interface into the dielectric, which probes only nanoparticles or molecules within a few hundred nanometres.

Kretschmann configuration: A prism-coupling arrangement in which light undergoes total internal reflection to excite surface plasmons on a thin metal film.

Refractive index: A dimensionless measure of how much light slows down and bends when entering a medium, key to sensing changes induced by nanoparticle binding.

Plasmonic scattering interferometry: A modulation technique that interferometrically isolates scattered plasmonic signals to enhance spatial resolution and suppress background noise.

References

1. Dynamic imaging of interfacial electrochemistry on single Ag nanowires by azimuth-modulated plasmonic scattering interferometry. Nature Communications (2023).
2. Principles of nanoparticle imaging using surface plasmons. New Journal of Physics (2015).
3. Spatial resolution in prism-based surface plasmon resonance microscopy. Optics Express (2014).