Surface-Enhanced Raman Scattering Techniques with MXene Substrates

Surface-enhanced Raman scattering (SERS) has emerged as a powerful optical tool for trace-level molecular detection, leveraging near-field amplification of Raman signals in the vicinity of tailored substrates. Two-dimensional transition metal carbides and nitrides, known as MXenes, have attracted considerable interest as SERS hosts owing to their metallic conductivity, tunable surface terminations and exceptional chemical stability. Layered MXenes such as Ti3C2Tx and Nb2C offer a high density of charge carriers that enhance electromagnetic fields at material discontinuities and facilitate charge-transfer resonance with target molecules. Furthermore, MXenes can be combined with noble metal nanoparticles or engineered into heterostructures to introduce abundant “hot spots”—regions of intensified local field—and to synergise electromagnetic and chemical enhancement pathways. Fabrication techniques including vacuum-assisted filtration, spin-casting, spray coating and electrostatic assembly have demonstrated precise control over layer thickness, surface roughness and nanoparticle distribution, which critically influence reproducibility and sensitivity. Applications span real-time pathogen screening, environmental pollutant monitoring and food safety analysis, exemplified by the detection of viral antigens, trace toxins and flavour compounds at sub-micromolar concentrations. Despite rapid progress, challenges remain in uniform large-scale production, long-term stability and the fundamental understanding of interfacial charge dynamics. Continued optimisation of MXene compositions, surface chemistry and hybrid architectures promises to advance SERS platforms towards routine diagnostic and field-deployable instruments.

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A comprehensive mini-review has outlined the current landscape of MXene-based SERS substrates, distinguishing between pristine MXene films and composites with noble metal nanoparticles. The authors examine representative biomedical, environmental and food-safety applications, underscore the role of surface termination groups in tuning chemical enhancement and highlight practical bottlenecks such as substrate degradation and batch variability.

Investigations into the correlation between MXene surface morphology and SERS performance have revealed that vacuum-assisted filtration yields dense, uniform Ti3C2Tx layers with enhanced spot-to-spot reproducibility and detection limits down to tens of nanomolar for standard dyes. In contrast, spray-coated films exhibit larger aggregates that localise analytes unevenly, reducing uniformity and sensitivity.

Studies of Nb2C and Ta2C MXenes have demonstrated exceptionally high enhancement factors—on the order of 10^6—through the synergistic action of charge-transfer resonance and electromagnetic amplification. These platforms achieved real-time detection of viral spike proteins at clinically relevant concentrations, illustrating the potential of MXene SERS for point-of-care diagnostics.

Surface-Enhanced Raman Scattering Techniques with MXene Substrates publication trend

The graph below shows the total number of articles in surface-enhanced raman scattering techniques with mxene substrates across all publications each year (not limited to Nature Index journals).

Technical terms

Surface-enhanced Raman scattering (SERS): An analytical technique that amplifies Raman scattering signals by exploiting localised electromagnetic fields near nanostructured substrates.

MXene: A family of two-dimensional transition metal carbides and nitrides with high electrical conductivity and controllable surface chemistry.

Hot spot: A nanoscale region where the local electromagnetic field is significantly intensified, enhancing Raman signal strength.

Charge-transfer resonance: A mechanism of chemical enhancement in SERS wherein electron exchange between substrate and analyte intensifies vibrational modes.

Enhancement factor: A quantitative measure of signal amplification in SERS, defined as the ratio of intensity with and without the enhancing substrate.

References

1. Charge-Transfer Resonance and Electromagnetic Enhancement Synergistically Enabling MXenes with Excellent SERS Sensitivity for SARS-CoV-2 S Protein Detection. Nano-Micro Letters (2021).
2. Substrate types and applications of MXene for surface-enhanced Raman spectroscopy. Frontiers in Chemistry (2024).
3. SERS Performance of Ti3C2Tx MXene-Based Substrates Correlates with Surface Morphology. Materials (2024).
4. Functionalized MXene (Ti3C2TX) Loaded with Ag Nanoparticles as a Raman Scattering Substrate for Rapid Furfural Detection in Baijiu. Foods (2024).