Recent advances in external physical field-assisted microfluidic SERS

Surface-enhanced Raman scattering (SERS) integrated with microfluidics offers low-consumption and high-specificity analysis, but conventional microfluidic-SERS (MF-SERS) remains constrained by laminar-flow-dominated passive diffusion, limited mass transfer, and poor signal reproducibility. This review summarizes recent advances in external physical field-assisted MF-SERS, highlighting how optical, electrical, magnetic, and acoustic fields enable active transport, localized enrichment, dynamic assembly, and in situ regeneration of analytes and SERS substrates. Key mechanisms, device architectures, and application scenarios are discussed, including photocatalysis, photothermal manipulation, optical tweezers, dielectrophoresis, electrochemical regulation, magnetic separation/assembly, and acoustofluidic control. Special focus is placed on the emerging role of artificial intelligence (AI) in adaptive spectral preprocessing, multicomponent classification, and quantitative analysis. By integrating multiphysics-field regulation with AI-driven analysis, MF-SERS is evolving from passive sensing toward automated, intelligent, and high-throughput analytical platforms. Finally, the review compares the characteristics of different field-assisted strategies and outlines future directions toward higher integration, portability, robustness, and real-world deployment.