Surface-Enhanced Raman Spectroscopy in Microfluidic Systems

Surface-Enhanced Raman Spectroscopy (SERS) in microfluidic platforms has emerged as a powerful approach for the rapid, sensitive and label-free analysis of chemical and biological analytes within confined volumes. By integrating plasmonic nanostructured substrates—typically noble metal features such as gold or silver—into microscale channels or droplets, SERS overcomes the inherently weak Raman scattering cross-section to deliver signal enhancements of several orders of magnitude. Microfluidic architectures, ranging from continuous-flow and droplet systems to open-channel designs, afford precise control over fluid handling, mixing and reaction kinetics. This synergy enables real-time monitoring of molecular events, high-throughput screening of reaction conditions and point-of-care diagnostics. Advances in substrate fabrication—such as laser-induced nanoparticle embedding, nanochain assembly and monolithic integration of nanoporous arrays—have driven improvements in sensitivity, reproducibility and reusability. The resulting platforms have been applied to trace-level detection of contaminants in water, multiplexed biomarker assays for disease diagnostics and in situ characterisation of rapid chemical transformations, underscoring the global significance of microfluidic SERS for environmental monitoring, clinical testing and fundamental research.

Research from Nature Portfolio

Researchers have developed a magnetic nanochain-integrated microfluidic biochip that unites rapid mixing, target separation and SERS-based signal transduction within a simple planar design. Magnetically actuated nanochains serve both as stirring elements and as affinity agents, while SERS-active nanoprobes enable parallel ultrasensitive detection of cancer protein biomarkers and bacterial species in microlitre samples within minutes. The device’s streamlined configuration, free of complex valves or mixers, demonstrates the potential of functionalised nanochains to accelerate on-chip assays and enhance assay kinetics in clinical and research settings.

Another cornerstone study describes a compact, battery-controlled SERS fluidic system for water-borne pollutant monitoring. Vertically aligned ZnO nanotapers decorated with silver nanoparticles are housed within a glass capillary alongside thermoresponsive microgels and gold nanorod colloids. Upon electrical heating, the microgels contract to capture analyte molecules and promote three-dimensional plasmonic coupling, generating dense hotspots for amplified Raman signals. This integrated device achieves trace-level detection of organophosphate pesticides and other small molecules with high reproducibility and offers simple regeneration via temperature cycling.

Research from all publishers

A novel femtosecond laser nanoparticle implantation technique has been harnessed to produce homogeneous gold nanoparticle arrays on flexible polymer films, which are then integrated into microfluidic chips for SERS analysis. The embedded arrays exhibit uniform electromagnetic field enhancement, enabling detection limits below ten parts per trillion for model contaminants and robust reusability after multiple cleaning cycles. This approach facilitates online monitoring of reaction pathways in flow, demonstrating a versatile route to durable and high-performance SERS substrates.

A comprehensive review of microfluidic systems for disease diagnostics highlights the diversification of channel designs—continuous-flow, microarray-embedded, droplet, digital droplet and gradient platforms—each tailored to enhance sample throughput, mixing efficiency and analyte confinement for SERS detection. The survey underscores key challenges in translating laboratory demonstrations into clinical practice, including substrate standardisation, fluidic integration and regulatory compliance, while mapping future directions for multiplexed biomarker panels and automated assay workflows.

Advances in 3D printed microfluidic devices have enabled the incorporation of Janus magnetic-plasmonic Fe₃O₄/Au nanostars as colloidal SERS substrates. By applying external magnetic fields, these multifunctional nanostars are localized at defined detection zones within printed channels, amplifying Raman signals for environmental and biomedical analytes. The rapid prototyping capability of 3D printing, coupled with magnetic trapping, allows quantitative assays in under thirty minutes using minimal sample volumes, paving the way for low-cost, scalable SERS sensing platforms.

Surface-Enhanced Raman Spectroscopy in Microfluidic Systems publication trend

The graph below shows the total number of articles in surface-enhanced raman spectroscopy in microfluidic systems across all publications each year (not limited to Nature Index journals).

Technical terms

Surface-Enhanced Raman Spectroscopy (SERS): A vibrational spectroscopy technique that exploits plasmonic nanostructures to amplify weak Raman signals by several orders of magnitude.

Microfluidics: The manipulation and control of small fluid volumes, typically microlitres to picolitres, within networks of channels measuring tens to hundreds of micrometres in diameter.

Plasmonic nanostructures: Nanometre-scale metallic features that support collective oscillations of conduction electrons, creating strong local electromagnetic fields.

Hotspots: Localised regions near plasmonic nanostructures where electromagnetic fields are greatly intensified, leading to enhanced Raman scattering.

Droplet microfluidics: A microfluidic modality in which discrete droplets serve as individual reaction vessels, enabling high-throughput parallel assays and precise control over mixing and incubation.

References

1. Femtosecond laser-induced nanoparticle implantation into flexible substrate for sensitive and reusable microfluidics SERS detection. International Journal of Extreme Manufacturing (2024).
2. Magnetic nanochain integrated microfluidic biochips. Nature Communications (2018).
3. A Surface-Enhanced Raman Scattering Sensor Integrated with Battery-Controlled Fluidic Device for Capture and Detection of Trace Small Molecules. Scientific Reports (2015).
4. Microfluidic surface-enhanced Raman scattering sensor with monolithically integrated nanoporous gold disk arrays for rapid and label-free biomolecular detection. Journal of Biomedical Optics (2014).
5. Microfluidics for disease diagnostics based on surface-enhanced raman scattering detection. Nano Convergence (2024).
6. 3D Printed Microfluidic Device for Magnetic Trapping and SERS Quantitative Evaluation of Environmental and Biomedical Analytes. ACS Applied Materials & Interfaces (2021).