Single-Cell Raman Spectroscopy Applications in Microbial Analysis

Single-cell Raman spectroscopy has emerged as a transformative, label-free technique for probing the biochemical heterogeneity of microbial cells at individual resolution. By measuring intrinsic molecular vibrations, this approach yields unique spectral fingerprints that reflect cellular composition, metabolic state and phenotypic adaptations without requiring external labels or extensive sample preparation. Applications span rapid species identification, antibiotic-susceptibility profiling, stress-response monitoring and microbial sorting. Advances in microfluidic integration, flow-cytometric coupling and surface-enhancement strategies have markedly increased throughput and sensitivity, enabling real-time classification of pathogens, elucidation of metabolic networks and in situ detection of antimicrobial resistance in complex environments.

Research from Nature Portfolio

Recent studies have refined single-cell spectral fingerprinting to probe microbial stress responses and resistance phenotypes. A biochemical fingerprinting approach termed “ramanome” collects single-cell Raman spectra across populations to quantify cytotoxicity and stress-response mechanisms, revealing marker bands that discriminate between antimicrobial, alcohol and heavy-metal challenges while tracking metabolic heterogeneity. In parallel, rapid antibiotic-susceptibility testing has been demonstrated by acquiring Raman spectra from individual bacterial cells after brief drug exposure, identifying spectral signatures of antibiotic action and enabling minimum inhibitory concentration estimation within hours without culture. Complementary work has linked label-free Raman spectral features to transcriptomic adaptations, showing that resistance acquisition induces metabolic shifts detectable through distinct peak intensities correlated with gene-expression changes, thereby bridging phenotypic and genotypic layers.

Single-Cell Raman Spectroscopy Applications in Microbial Analysis publication trend

The graph below shows the total number of articles in single-cell raman spectroscopy applications in microbial analysis across all publications each year (not limited to Nature Index journals).

Technical terms

Single-cell Raman spectroscopy (SCRS): Label-free optical method capturing vibrational spectra of individual cells to reveal biochemical composition.

Ramanome: Composite collection of SCRS from a population, serving as a metabolic phenome fingerprint to quantify heterogeneity and stress responses.

Raman flow cytometry: Integration of Raman spectroscopy with microfluidic flow cytometry for automated, high-throughput analysis of single-cell spectra.

Raman stable isotope probing (Raman-SIP): Technique using isotopically labelled substrates (e.g. 13C, D2O) to trace incorporation into cellular biomass via Raman shifts.

Surface-enhanced Raman spectroscopy (SERS): Plasmonic approach using metallic nanostructures to amplify Raman scattering signals for enhanced sensitivity.

pDEP-DLD: Periodic positive dielectrophoresis induced deterministic lateral displacement, a microfluidic cell-focusing mechanism for stable Raman interrogation.

References

1. Robust Spontaneous Raman Flow Cytometry for Single‐Cell Metabolic Phenome Profiling via pDEP‐DLD‐RFC. Advanced Science (2023).
2. Label-free, rapid and quantitative phenotyping of stress response in E. coli via ramanome. Scientific Reports (2016).
3. Culture-free Antibiotic-susceptibility Determination From Single-bacterium Raman Spectra. Scientific Reports (2018).
4. Raman spectral signature reflects transcriptomic features of antibiotic resistance in Escherichia coli. Communications Biology (2018).
5. Continuous cell sorting in a flow based on single cell resonance Raman spectra. Lab on a Chip (2016).
6. Reverse and Multiple Stable Isotope Probing to Study Bacterial Metabolism and Interactions at the Single Cell Level. Analytical Chemistry (2016).
7. Raman-Deuterium Isotope Probing for in-situ identification of antimicrobial resistant bacteria in Thames River. Scientific Reports (2017).