Quantifying the degradation of extracellular polysaccharides of Escherichia coli by CdS quantum dots

Abstract

For the first time, we report the degradative ability of CdS QDs on extracellular polysaccharides of E. coli cells. The optimal concentration at which EPS peak enhancement is observed and beyond which concentration the degradative activity of CdS QDs become significant has been demonstrated. 20 mL L À1 of CdS QDs lead to enhancement of EPS peaks upto incubation time of 3h. Concentration above 50 mL L À1 CdS showed significant EPS degradation. The EPS degradation by the CdS QDs has been quantified and the significance has been statistically analyzed using Tukey-Kramer Multiple comparison test. We have also defined the enrichment and degradation rate and calculated these rates based on the increasing or decreasing of EPS peaks detected from the MALDI-MS spectra.

Electrospray ionization and matrix‐assisted laser desorption/ionization mass spectrometric analysis of extrapolysaccharides of Escherichia coli

“…This indicated that, irrespective of the mass spectrometric technique, these peaks appear when analyzing E. coli EPS. We have previously discussed the effectiveness of using MALDI‐MS for analysis of EPS and have proved that the low‐mass peaks belong to the EPS moieties related to the slime layer of bacterial cells …”

Future perspective of nanoparticle interaction‐assisted laser desorption/ionization mass spectrometry for rapid, simple, direct and sensitive detection of microorganisms

“…We have already tested the use of Quantum Dot interaction‐assisted laser desorption/ionization mass spectrometry (QDIALDI‐MS) for microorganism research and have found that CdS QDs are effective in enabling the rapid, sensitive and direct detection detection of fungi such as Saccharomyces cereviesea and Candida utilis . CdS QDs proved to be useful for the rapid, sensitive and direct detection of EPS molecules secreted by E.coli . Our ongoing studies with CdS, CdSe and ZnO QDs suggest that QDs are more versatile than the NPs and hence would significantly enhance the sensitivity of the NPILDI‐MS technique.…”

“…CdS QDs proved to be useful for the rapid, sensitive and direct detection of EPS molecules secreted by E.coli. [50] Our ongoing studies with CdS, CdSe and ZnO QDs suggest that QDs are more versatile than the NPs and hence would significantly enhance the sensitivity of the NPILDI-MS technique. Figure 7 gives an overview of the current scenario of NPILDI-MSbased rapid, sensitive and direct detection of microorganisms and also projects the future extension this technique.…”

Recent Advances in Bacteria Identification by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Using Nanomaterials as Affinity Probes

“…Gopal et al [ 71 ] has reported that CdS QDs can degrade the extracellular polysaccharides of E. coli cells when using MALDI-MS. Adding 20 μL/L of CdS QDs was observed to enhance the extracellular polymeric substance (EPS) peaks using an incubation time of up to 3 h. The authors confirmed that CdS QDs can function as more than just affinity probes, being able to degrade EPSs.…”