Diagnose Pathogens in Drinking Water via Magnetic Surface-Enhanced Raman Scattering (SERS) Assay

Abstract

Rapid identification and diagnosis of bacteria and other microorganisms is a great challenge for drinking water safety due to the increasing frequency of pathogenic infections. Raman spectroscopy is a non-destructive tool to characterize the biochemical fingerprints of bacterial cells and its signal can be improved by surface-enhanced Raman scattering (SERS). Thus, Raman scattering has a huge potential in fast diagnosis of pathogens in drinking water, with low cost and high reproducibility. In this work, we developed a novel fast diagnosis method to detect aquatic pathogens via magnetic SERS assay. With chemical co-precipitation synthesis and surface glucose reduction, the silver coated magnetic nanoparticles (Ag@MNPs) had a well-developed core-shell structure and high efficiency to capture bacterial cells. Ag@MNPs achieved 10 3 enhancement factor for rhodamine 6G and the limit of detection was 10-9 M. The magnetic SERS assay also successfully detected various bacteria (A. baylyi and E. coli) with high sensitivity (10 5 CFU/mL). This platform provided a promising and easy-operation approach for pathogen detection for food and drinking water safety.

Application of Raman Spectroscopic Methods in Food Safety: A Review

“…Another study used silver-coated magnetic nanoparticles to capture Acintobacter baylyi and E. coli in drinking water for the detection by SERS. This detection method showed a sensitivity of 10 5 CFU/mL and achieved rapid screening of bacteria in water in less than 15 min [43]. Krafft and co-authors developed a microfluidic device that trapped and concentrated bacterial cells of E. coli and Pseudomonas as well as aggregated silver nanoparticles from tap water by the electrokinetic flow of the sample across a porous membrane.…”

Applications of Iron Oxide-Based Magnetic Nanoparticles in the Diagnosis and Treatment of Bacterial Infections

“…In order to make the most of SERS for bacterial detection and monitoring, it is desirable to combine MNPs with SERS to construct a method for bacteria capture and detection (Liu et al, 2011). Recently, Fe 3 O 4 @Ag (Fargašová et al, 2017; Wang et al, 2018a) and Ag@Fe 3 O 4 (Li et al, 2017a) composite MNPs have been constructed and modified with different target molecules such as vancomycin for a wide range of bacteria, biotinylated antibodies for both S. aureus , and Streptococcus pyogenes ( S. pyogenes ), for pathogenic bacteria separation and detection. Wang and co-researchers presented a sensitive MNPs-assisted SERS biosensor based on Fe 3 O 4 @Ag MNPs and Au@Ag NPs to effectively capture and discriminate bacteria.…”

The Rocky Road From Fed-Batch to Continuous Processing With E. coli

“…Esmonde-White et al found that Raman spectroscopy is already applied in GMP facilities (good manufacturing practice) for monoclonal antibody (mAB) production (Esmonde-White et al, 2017). Raman spectroscopy can be found in diverse fields, ranging from bacterial impurity measurement of water (Li et al, 2017) to surface-enhanced Raman spectroscopy (SERS), which can be used to determine bacterial contaminations in cell cultures (Esmonde-White et al, 2017). Teng et al monitored stress reactions using Raman spectroscopy on a single-cell bacterial level (Teng et al, 2016), and overflow metabolites in an E. coli fermentation were monitored by Lee et al using online Raman spectroscopy (Lee et al, 2004).…”

“…Mammalian cell cultivations for RPP already make use of RAMAN- and NIR-signals (Iversen et al, 2014; Berry et al, 2015; Esmonde-White et al, 2017; Li et al, 2017), and even have implemented signal-derived feedback controls (Li et al, 2013; Craven et al, 2014). As the major advantage of microbial processes compared to mammalian cell line cultivations is the cheap manufacturing, the devices and detectors needed for Raman and NIR spectroscopy are possibly too high in price to establish microbial process controls until now (Rathore, 2014).…”