Surface‐Enhanced Raman Spectroscopy for the Detection of a Metabolic Product in the Headspace Above Live Bacterial Cultures

Abstract

In situ surface‐enhanced Raman spectra of the headspace above cultures of six bacterial species showed strong characteristic bands from chemisorbed methyl sulfide. This marker compound is created by dissociation of dimethyl disulfide (DMDS), a fermentative metabolite of bacteria, on the surface of the enhancing Au or Ag nanoparticle films. Kinetic binding plots of media spiked with DMDS and of live cultures showed that the Au‐based substrates were more suitable for the rapid detection of bacteria than Ag‐based substrates. For E. coli DH5α, the sensitivity limit for headspace SERS detection was 1.5×107 CFU mL−1, which corresponded to detection 15 min after inoculation of the growth medium. Since the metabolites are only produced by viable bacteria, antibiotic (gentamicin) treatment stopped the normal signal growth of the marker peak. This work is a promising step towards rapid bedside detection of bacterial infections and rapid screening of antibiotics against bacteria.

Present and Future of Surface-Enhanced Raman Scattering

“…The first study by Premasiri et al showed that purine-related molecules were predominantly measured by SERS of intact bacteria, while other studies using SERS-SIP have also used this principle for the same purpose. , This approach has also been used to image single bacterial cells and to identify phenotypic function in mixed communities . Surface-enhanced Raman scattering is becoming a powerful tool for characterizing bacterial pathogens, and this method can be used to assess antibiotic susceptibility or resistance, both by probing the bacteria directly or by measuring the volatile organic compounds from the headspace of bacteria cultures …”

Ta@Ag Porous Array with High Stability and Biocompatibility for SERS Sensing of Bacteria

“…However, due to the poor chemical stability and photostability of the substrate, irreversible adsorption of an organic agent during wet chemical preparation, , and invasion of the biological sample, the ideal SERS detection with supersensitivity and higher steadiness still faces many challenges . Pathogen is a kind of high-impact biological cell; rapid and in situ sensing of bacteria could help to assess the effectiveness of antibiotics and combat “superbug” infections or antimicrobial resistance . Currently, the optical detection of bacterial signal mainly relies on bacterial biosensors carrying foreign reporter genes.…”

“…8 Pathogen is a kind of high-impact biological cell; rapid and in situ sensing of bacteria could help to assess the effectiveness of antibiotics and combat "superbug" infections or antimicrobial resistance. 9 Currently, the optical detection of bacterial signal mainly relies on bacterial biosensors carrying foreign reporter genes. This method requires a complex process of gene editing for expressing bioluminescent proteins or fluorescent proteins.…”

Quantitative Analysis of Salmonella typhimurium Based on Elemental-Tags Laser-Induced Breakdown Spectroscopy

“…At present, traditional bacterial detection methods including pure culture, enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR) are still widely used as gold standards. − However, the shortcomings of being time-consuming and labor-intensive make them difficult to meet the requirement of high timeliness. As alternatives, some new technologies such as inductively coupled plasma mass spectrometry (ICPMS) , and surface-enhanced Raman spectroscopy (SERS) , have been reported for pathogen detection. Although they have played a vital role in the investigation and development of biology, they usually suffer from the unsatisfactory defects of dependence on sample preparation and complicated working procedures. − Therefore, it is imperative to establish a set of bacterial detection systems with easy operation and rapid detection.…”

“…6−9 However, the shortcomings of being time-consuming and labor-intensive make them difficult to meet the requirement of high timeliness. As alternatives, some new technologies such as inductively coupled plasma mass spectrometry (ICPMS) 10,11 and surfaceenhanced Raman spectroscopy (SERS) 12,13 have been reported for pathogen detection. Although they have played a vital role in the investigation and development of biology, they usually suffer from the unsatisfactory defects of dependence on sample preparation and complicated working procedures.…”