Surface-Enhanced Raman Spectroscopy Substrates for Analyte Detection

Surface-enhanced Raman spectroscopy (SERS) offers unparalleled sensitivity for molecular fingerprinting by exploiting the intense electromagnetic fields generated at nanostructured surfaces. Substrates are engineered to create dense “hot-spots” where analyte molecules experience extreme field enhancement, yielding signal amplifications of up to 10^12 times. Advances in material composition, topology and wettability allow substrates to concentrate trace analytes from liquids, solids and gases into these active regions. Designs range from metal plasmonic arrays to carbon-based and levitated platforms, each balancing sensitivity, reproducibility and durability. Recent efforts emphasise scalable fabrication, directional enrichment and compatibility with portable Raman spectrometers, unlocking applications in environmental monitoring, point-of-care diagnostics and in situ chemical sensing.

Research from Nature Portfolio

Recent studies have demonstrated a metal-free nanowire array composed of porous carbon that achieves signal enhancement comparable to plasmonic metals through strong broadband charge-transfer resonance. The absence of hot-spot dependence confers exceptional uniformity, biocompatibility and resistance to oxidation. A levitated-droplet platform uses acoustic levitation to suspend volatile droplets, enabling lossless concentration of analytes and metal nanoparticles into a confined volume. This approach yields attomolar detection limits without surface coatings and extends to multiphase samples. Another work introduces buoyant plasmonic particles on a slippery surface to prevent coffee-ring effects, driving analyte aggregation at few-to-single-particle junctions. The resulting sensors detect molecules at femto- to attomolar levels with simple, cost-effective fabrication.

Research from all publishers

A hierarchical silver/fluoroalkyl-modified substrate employs a double-layer design combining superhydrophobic micro-armour structures with anodic aluminium oxide nanopillars. The superhydrophobic layer concentrates analyte droplets into nanopillar arrays, generating ordered hot-spots and achieving detection limits down to 10^–7 M. In another development, superhydrophobic ZnO/Ag nanowires draw trace antibiotics from water into the tips of nanowires, aligning analyte molecules with enhanced fields for in situ detection in harsh aqueous environments at 10^–9 M levels. Wearable sensors based on ultrathin gold nanomesh demonstrate scalable fabrication of flexible SERS substrates. These can be adhered to skin or surfaces for label-free, in situ monitoring of sweat biomarkers, drugs and microplastics across concentration ranges spanning 10^–9 to 10^–1 M.

Surface-Enhanced Raman Spectroscopy Substrates for Analyte Detection publication trend

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

Technical terms

Localized Surface Plasmon Resonance (LSPR): optical phenomenon where conduction electrons in metal nanostructures resonate with incident light, amplifying the electromagnetic field at the surface.

Hot spot: nanoscale region of intense electromagnetic field enhancement, critical for high SERS sensitivity.

Enhancement factor (EF): ratio quantifying the increase in Raman signal intensity due to the SERS substrate compared to normal Raman scattering.

Detection limit: the lowest concentration of analyte that can be reliably identified by the SERS substrate.

Acoustic levitation: technique using sound waves to suspend droplets, enabling lossless analyte enrichment during evaporation.

Hydrophobicity: property of a surface that repels water, used to concentrate analytes by minimising contact area.

Nanowire array: ordered arrangement of nanoscale wires offering uniform SERS activity through controlled charge-transfer resonance or plasmonic effects.

References

1. Porous carbon nanowire array for surface-enhanced Raman spectroscopy. Nature Communications (2020).
2. Lossless enrichment of trace analytes in levitating droplets for multiphase and multiplex detection. Nature Communications (2022).
3. Buoyant particulate strategy for few-to-single particle-based plasmonic enhanced nanosensors. Nature Communications (2020).
4. In Situ Raman Monitoring of Trace Antibiotics in Different Harsh Water Environments. Energy & Environmental Materials (2023).
5. Highly Scalable, Wearable Surface‐Enhanced Raman Spectroscopy. Advanced Optical Materials (2022).