Amplification of surface-enhanced Raman scattering by the oxidation of capping agents on gold nanoparticles

Gorbachevskii, M. V.; Копицын, Д. С.; Котелев, М. С.; Иванов, Е. В.; Винокуров, В. А.; Новиков, А. А.

doi:10.1039/c8ra00417j

Cited by 18 publications

(10 citation statements)

References 41 publications

(54 reference statements)

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“…(Efrima and Zeiri, 2009) and discriminate between bacteria, at least at the genus level (Kopitsyn et al, 2019). Surface-enhanced Raman scattering (SERS) substrates were prepared as described elsewhere (Gorbachevskii et al, 2018; Kopitsyn et al, 2019).…”

Section: Methodsmentioning

confidence: 99%

Composition of the Biofilm Matrix of Cutibacterium acnes Acneic Strain RT5

et al. 2019

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In skin, Cutibacterium acnes (former Propionibacterium acnes ) can behave as an opportunistic pathogen, depending on the strain and environmental conditions. Acneic strains of C. acnes form biofilms inside skin–gland hollows, inducing inflammation and skin disorders. The essential exogenous products of C. acnes accumulate in the extracellular matrix of the biofilm, conferring essential bacterial functions to this structure. However, little is known about the actual composition of the biofilm matrix of C. acnes . Here, we developed a new technique for the extraction of the biofilm matrix of Gram-positive bacteria without the use of chemical or enzymatic digestion, known to be a source of artifacts. Our method is based on the physical separation of the cells and matrix of sonicated biofilms by ultracentrifugation through a CsCl gradient. Biofilms were grown on the surface of cellulose acetate filters, and the biomass was collected without contamination by the growth medium. The biofilm matrix of the acneic C. acnes RT5 strain appears to consist mainly of polysaccharides. The following is the ratio of the main matrix components: 62.6% polysaccharides, 9.6% proteins, 4.0% DNA, and 23.8% other compounds (porphyrins precursors and other). The chemical structure of the major polysaccharide was determined using a nuclear magnetic resonance technique, the formula being →6)-α- D -Gal p -(1→4)-β- D -Man p NAc3NAcA-(1→6)-α- D -Glc p -(1→4)-β- D -Man p NAc3NAcA-(1→3)-β-Gal p NAc-(1→. We detected 447 proteins in the matrix, of which the most abundant were the chaperonin GroL, the elongation factors EF-Tu and EF-G, several enzymes of glycolysis, and proteins of unknown function. The matrix also contained more than 20 hydrolases of various substrata, pathogenicity factors, and many intracellular proteins and enzymes. We also performed surface-enhanced Raman spectroscopy analysis of the C. acnes RT5 matrix for the first time, providing the surface-enhanced Raman scattering (SERS) profiles of the C. acnes RT5 biofilm matrix and biofilm biomass. The difference between the matrix and biofilm biomass spectra showed successful matrix extraction rather than simply the presence of cell debris after sonication. These data show the complexity of the biofilm matrix composition and should be essential for the development of new anti- C. acnes biofilms and potential antibiofilm drugs.

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Section: Methodsmentioning

confidence: 99%

Composition of the Biofilm Matrix of Cutibacterium acnes Acneic Strain RT5

et al. 2019

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“…At a higher concentration of R6G (10 −3 M) the SERS intensity slows, due to complete AuNP aggregation and saturation of ‘hot spots’ by the adsorbed dye (Fig. 2c , green line) 35 . Overall, the analytical enhancement factor (AEF) for Au substrate (λ max = 519 nm) using handheld-SERS could be calculated as 8.04 × 10 3 , using the main characteristic peak of R6G at 1362 cm −1 , in the absence and presence of AuNPs (Supplementary Eq.…”

Section: Resultsmentioning

confidence: 99%

Handheld SERS coupled with QuEChERs for the sensitive analysis of multiple pesticides in basmati rice

et al. 2022

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Pesticides are a safety issue globally and cause serious concerns for the environment, wildlife and human health. The handheld detection of four pesticide residues widely used in Basmati rice production using surface-enhanced Raman spectroscopy (SERS) is reported. Different SERS substrates were synthesised and their plasmonic and Raman scattering properties evaluated. Using this approach, detection limits for pesticide residues were achieved within the range of 5 ppb-75 ppb, in solvent. Various extraction techniques were assessed to recover pesticide residues from spiked Basmati rice. Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERs) acetate extraction was applied and characteristic spectral data for each pesticide was obtained from the spiked matrix and analysed using handheld-SERS. This approach allowed detection limits within the matrix conditions to be markedly improved, due to the rapid aggregation of nanogold caused by the extraction medium. Thus, detection limits for three out of four pesticides were detectable below the Maximum Residue Limits (MRLs) of 10 ppb in Basmati rice. Furthermore, the multiplexing performance of handheld-SERS was assessed in solvent and matrix conditions. This study highlights the great potential of handheld-SERS for the rapid on-site detection of pesticide residues in rice and other commodities.

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“…SERS studies were carried out with a BWS415 micro‐Raman spectrometer (BWTEC, Germany) equipped with a 785 nm laser (see for details ref. ). The sample was put on the XYZ stage, and the position of the laser focus was controlled via a USB microscope, Mikmed‐2000R (Micromed, Saint‐Petersburg, Russia).…”

Section: Methodsmentioning

confidence: 97%

Plasmonic Properties of Halloysite Nanotubes with Immobilized Silver Nanoparticles for Applications in Surface‐Enhanced Raman Scattering

Kornilova

Gorbachevskii

Kuralbayeva

et al. 2019

Physica Status Solidi (a)

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Halloysite nanotubes (HNTs) with surface-immobilized silver (Ag) nanoparticles (NPs) are explored as nano-templates for the surface-enhanced Raman scattering (SERS). The structure and plasmonic properties of HNTs/ Ag nanocomposite during storage in water are checked by means of the transmission electron microscopy and optical absorption spectroscopy, respectively. A remarkable SERS response is observed for and the SERS activity of HNTs/Ag stored in water for 1 week decreases by several times. The observed SERS-activity is explained by desired morphology of Ag NP distribution on the surface of HNTs, which is modified during storage in aqueous medium. The revealed SERS activity of HNTs/Ag nanocomposites seems to be promising for their application in biosensorics.

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Amplification of surface-enhanced Raman scattering by the oxidation of capping agents on gold nanoparticles

Abstract: The intensity of a surface-enhanced Raman scattering signal can be amplified by the peroxide-induced oxidation of citrate capping agents on gold nanoparticles.

Cited by 18 publications

References 41 publications

Composition of the Biofilm Matrix of Cutibacterium acnes Acneic Strain RT5

Composition of the Biofilm Matrix of Cutibacterium acnes Acneic Strain RT5

Handheld SERS coupled with QuEChERs for the sensitive analysis of multiple pesticides in basmati rice

Plasmonic Properties of Halloysite Nanotubes with Immobilized Silver Nanoparticles for Applications in Surface‐Enhanced Raman Scattering

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