Surface-Enhanced Raman Scattering (SERS) in Microbiology: Illumination and Enhancement of the Microbial World

Abstract

The microbial world forms a huge family of organisms that exhibit the greatest phylogenetic diversity on Earth and thus colonize virtually our entire planet. Due to this diversity and subsequent complex interactions, the vast majority of microorganisms are involved in innumerable natural bioprocesses and contribute an absolutely vital role toward the maintenance of life on Earth, whilst a small minority cause various infectious diseases. The ever-increasing demand for environmental monitoring, sustainable ecosystems, food security, and improved healthcare systems drives the continuous search for inexpensive but reproducible, automated and portable techniques for detection of microbial isolates and understanding their interactions for clinical, environmental, and industrial applications and benefits. Surface-enhanced Raman scattering (SERS) is attracting significant attention for the accurate identification, discrimination and characterization and functional assessment of microbial cells at the single cell level. In this review, we briefly discuss the technological advances in Raman and Fourier transform infrared (FT-IR) instrumentation and their application for the analysis of clinically and industrially relevant microorganisms, biofilms, and biological warfare agents. In addition, we summarize the current trends and future prospects of integrating Raman/SERS-isotopic labeling and cell sorting technologies in parallel, to link genotype-to-phenotype in order to define community function of unculturable microbial cells in mixed microbial communities which possess admirable traits such as detoxification of pollutants and recycling of essential metals.

Label‐free serum detection based on Raman spectroscopy for the diagnosis and classification of glioma

“…The peak assignments are listed in Table 3 according to the reported literature. [11,14,[21][22][23][24][25][26][27][28] The HGG and LGG group peak intensity changes compared with the normal group are shown in Table 2. The HGG group had lower intensities than the LGG group at all specific peaks except 749 cm −1 .…”

“…T A B L E 3 Raman peak attribution in normal and glioma serum [11,14,[21][22][23][24][25][26][27][28] Raman shift (cm − PCA-LDA for glioma diagnosis, an ROC curve was produced, as shown in Figure 3b, and the accuracy of the discriminant analysis results was evaluated by the area under the ROC curve. Therefore, we performed a pairwise comparison of the PCA-LDA diagnostic algorithm results.…”

Detection and Characterization of Antibiotic-Resistant Bacteria Using Surface-Enhanced Raman Spectroscopy

“…SERS is a derivative of Raman spectroscopy with the aid of nanomaterials. Numerous research studies have been conducted during the past four decades about using SERS for trace detection of the targeted analytes [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Different from the conventional Raman spectroscopic technology, SERS signal can be significantly enhanced due to both electromagnetic enhancement and chemical enhancement, with the former being the dominant contributor [ 24 ].…”

Discrimination of bacteria using whole organism fingerprinting: the utility of modern physicochemical techniques for bacterial typing

“…For information on quantification of analytes and bacteria by SERS the reader is direct to these recent reviews. 83,104,112 Finally, perhaps the most exciting aspect of Raman spectroscopy is that it is possible to measure single bacteria. This is because the excitation source used for Raman is a UV to near IR laser is highly focused and thus possesses similar dimensions to bacterial cells (ca.…”

“…A further study carried out by Schmilovitch et al101 enabled clear distinction between Gram-positive andGram-negative bacteria using Raman spectroscopy with a diode laser of 785 nm excitation.These examples provide evidence that Raman spectroscopy can be used for the analysis of bacterial samples using various sample preparation methods, instrumentation parameters and chemometrics tools.Although Raman spectroscopy exhibit poor quantum efficiency in comparison to IR spectroscopic techniques, SERS is often employed to enhance Raman signals, resulting in increased sensitivity down to single molecule detection 102. SERS involves the measurement of the interactions between plasmonic metallic nanoparticles (NPs) and sample molecules; these molecules can be in direct contact to or reside in close proximity to the NP surface 103,104. Although the SERS enhancement mechanisms are still inconclusive, and that the debate is still ongoing within the SERS community105 , the enhancement of the Raman scattering observed via SERS method is largely due to the incident excitation frequency being resonant with the surface plasmon resonance in metallic nanostructures; the so-called localised surface plasmon resonance (LSPR).…”