Advances in surface plasmon resonance imaging research (<i>invited</i>)

Fig. 2. Schematic of surface plasma waves on metal and dielectric surfaces

Fig. 3. Imaging device diagram. (a) SPR imaging device with Kretschmann structure^[28]; (b) Picture of multispectral SPRI system^[30]; (c) Picture of SPR imaging device^[31]

Fig. 4. Experimental setup for measuring time-varying ethanol concentration and droplet geometry^[32]

Fig. 5. Experimental setup for imaging individual dielectric nanoparticles^[35]

Fig. 6. Schematic diagram of biosensor^[39]

Fig. 7. Schematic diagram of SPR polarization contrast method^[40]

Fig. 8. Schematic diagram of super-resolution SPRC optical microscope^[42]

Fig. 9. Composite field microimaging system diagram^[45]

Fig. 10. Experimental setup for enhanced Raman spectral detection and imaging^[47]

Fig. 11. SPR imaging system schematic^[51]

Fig. 12. Schematic of PC SMi biosensor^[52]

Fig. 13. System schematic. (a) Optical system schematic^[58]; (b) Surface plasmon resonance holographic microscope setup^[59]

Fig. 14. Schematic diagram of the SPRI biosensing approach^[63]

Fig. 15. Biosensing schematic^[64]

Fig. 16. Schematic diagram of a sensing scheme for indirect detection of adenovirus using SPRI-based biosensors^[69]

Fig. 17. Schematic representation of SARS-CoV-2 S protein detection using a DNA aptamer-based SPRI sensor^[74]

Table 1. Summary of SPRI basic principles

Table 1. Summary of SPRI basic principles

SPRI basic principle	Description
SPR principle	Monitoring of intermolecular interactions using light interacting with free electrons on metal surfaces to form surface plasmon resonances
SPRI principle	Combining SPR technology with imaging technology to detect molecular interactions in real time by monitoring changes in the refractive index on the surface of a biochip

Table 2. Summary of SPRI technology classifications

Table 2. Summary of SPRI technology classifications

SPRI technology classification		Description
Prism-coupled SPRI		A prism is utilized to direct incident light to the metal surface to form a plasma wave, and the binding is quantified by measuring the SPR angular shift due to biomolecular interactions
Non prism-coupled SPRI		Simplified system architecture using optical fibers or waveguides to guide light directly to the metal film enables real-time monitoring of biomolecular interactions

Table 3. Summary of new advances in imaging technology

Table 3. Summary of new advances in imaging technology

New advances in imaging technology	Description
Improvement in spatial resolution	Optimization of the optical system combined with the adoption of a nanostructured design improves imaging clarity and achieves nanoscale spatial resolution for fine observation of biomolecules
Multi-modal imaging fusion	SPRI combines a variety of imaging techniques, such as fluorescence, Raman, infrared and terahertz imaging, and has become an important direction of development, providing a comprehensive analysis of biomolecules and a multi-dimensional detection perspective
Real-time dynamic imaging development	High-speed imaging technology, optimized data processing algorithms and microfluidic technology are used to achieve real-time monitoring of the dynamic change process of biomolecules

Table 4. Summary of applications in the field biosensing