Tryptophan-functionalized gold nanoparticles for deep UV imaging of microbial cells

Pajović, Jelena; Dojčilović, Radovan; Božanić, Dušan K.; Kaščáková, Slávka; Réfrégiers, Matthieu; Dimitrijević-Branković, Suzana; Vodnik, Vesna; Milosavljević, Aleksandar R.; Piscopiello, E.; Luyt, A. S.; Djoković, Vladimir

doi:10.1016/j.colsurfb.2015.08.050

Cited by 36 publications

(21 citation statements)

References 25 publications

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“…Under these conditions, the photoluminescence of TiO 2 particles enables tracking their accumulation in bacteria with a higher spatial resolution compared to conventional optical methods ( Jamme et al, 2010 ). In previous works, this technique has been successfully employed to probe the distribution of antimicrobials in Enterobacter aerogenes ( Kašèáková et al, 2012 ) as well as the accumulation of tryptophan-functionalized gold and silver nanoparticles in E. coli ( Pajović et al, 2015 ; Dojčilović et al, 2016 ). Here, DUV fluorescence imaging with single-cell resolution revealed TiO 2 /cell co-localization by enabling to distinguish between the fluorescent signal pertaining to TiO 2 particles and the autofluorescence of treated E. coli or L. lactis bacterial cells.…”

Section: Discussionmentioning

confidence: 99%

“…Deep ultraviolet fluorescence imaging of E. coli K12 MG1655 and L. lactis IBB477 cells after TiO 2 exposure was carried out on a Zeiss Axio Observer Z-1 microscope at the DISCO beamline ( Giuliani et al, 2009 ) of the SOLEIL synchrotron facility, as previously described for tryptophan-functionalized gold ( Pajović et al, 2015 ) and silver nanoparticles ( Dojčilović et al, 2016 ). Bacterial cells were cultured in appropriate medium containing TiO 2 at a concentration of 320 μg/mL (aggregated vs. dispersed forms, E171 vs. P25), collected at the stationary phase of growth and washed twice in phosphate buffered saline (5000 g, 5 min, room temperature).…”

Section: Methodsmentioning

confidence: 99%

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Toxicity of Food-Grade TiO2 to Commensal Intestinal and Transient Food-Borne Bacteria: New Insights Using Nano-SIMS and Synchrotron UV Fluorescence Imaging

et al. 2018

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Titanium dioxide (TiO2) is commonly used as a food additive (E171 in the EU) for its whitening and opacifying properties. However, a risk of intestinal barrier disruption, including dysbiosis of the gut microbiota, is increasingly suspected because of the presence of a nano-sized fraction in this additive. We hypothesized that food-grade E171 and Aeroxyde P25 (identical to the NM-105 OECD reference nanomaterial in the European Union Joint Research Centre) interact with both commensal intestinal bacteria and transient food-borne bacteria under non-UV-irradiated conditions. Based on differences in their physicochemical properties, we expect a difference in their respective effects. To test these hypotheses, we chose a panel of eight Gram-positive/Gram-negative bacterial strains, isolated from different biotopes and belonging to the species Escherichia coli, Lactobacillus rhamnosus, Lactococcus lactis (subsp. lactis and cremoris), Streptococcus thermophilus, and Lactobacillus sakei. Bacterial cells were exposed to food-grade E171 vs. P25 in vitro and the interactions were explored with innovative (nano)imaging methods. The ability of bacteria to trap TiO2 was demonstrated using synchrotron UV fluorescence imaging with single cell resolution. Subsequent alterations in the growth profiles were shown, notably for the transient food-borne L. lactis and the commensal intestinal E. coli in contact with food-grade TiO2. However, for both species, the reduction in cell cultivability remained moderate, and the morphological and ultrastructural damages, observed with electron microscopy, were restricted to a small number of cells. E. coli exposed to food-grade TiO2 showed some internalization of TiO2 (7% of cells), observed with high-resolution nano-secondary ion mass spectrometry (Nano-SIMS) chemical imaging. Taken together, these data show that E171 may be trapped by commensal and transient food-borne bacteria within the gut. In return, it may induce some physiological alterations in the most sensitive species, with a putative impact on gut microbiota composition and functioning, especially after chronic exposure.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Toxicity of Food-Grade TiO2 to Commensal Intestinal and Transient Food-Borne Bacteria: New Insights Using Nano-SIMS and Synchrotron UV Fluorescence Imaging

et al. 2018

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“…During the next several hours (3-12 h), AuNCs become more ordered inside the protein due to structural optimization [32]. Furthermore, it is known that tyrosine and tryptophan are able to reduce Au(III) under strongly alkaline pH values to Au(0), thus forming AuNCs and nanoparticles [42][43][44]. Therefore, cysteine, tyrosine, and tryptophan residues are visualized in Figure 1.…”

Section: Bsa Structural Changes In the Course Of Auncs Synthesismentioning

confidence: 99%

The Effect of Fatty Acids and BSA Purity on Synthesis and Properties of Fluorescent Gold Nanoclusters

et al. 2020

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Fluorescent gold nanoclusters (AuNCs) are envisaged as a novel type of fluorophores. This work reports on the first comparative study investigating the effect of presence/absence/abundance of fatty acids (namely palmitic acid, PA) or other substances (like glycoproteins and globulins) in the protein (bovine serum albumin, BSA) on synthesis and properties of the final AuNCs. The most popular template (BSA) and microwave (MW)-assisted synthesis of AuNCs have been intentionally chosen. Our results clearly demonstrate that the fluorescent characteristics (i.e., fluorescence lifetime and quantum yield) are affected by the fatty acids and/or other substances. Importantly, the as-prepared AuNCs are biocompatible, as determined by Alamar Blue assay performed on Hep G2 cell line.

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“…[16][17][18][19][20] This technique allows excitation of fluorophores below 300 nm that is a major advantage in terms of the resolution of fluorescence images in comparison with conventional imaging techniques. In our latest study, 20 we developed a method for functionalization of gold nanoparticles with UV fluorescent tryptophan biomolecules. The obtained hybrid nanostructures emitted radiation in the UV region that provided the detection of the nanostructures within bacteria by the DUV fluorescence imaging technique with high spatial resolution (one pixel ∼150 nm).…”

Section: Introductionmentioning

confidence: 99%

“…We tried to probe the interaction of silver nanoparticles with live E. coli cells and for that reason we used a non-invasive optical deep ultraviolet (DUV) fluorescence imaging method. [16][17][18][19][20] This technique allows excitation of fluorophores below 300 nm that is a major advantage in terms of the resolution of fluorescence images in comparison with conventional imaging techniques. In our latest study, 20 we developed a method for functionalization of gold nanoparticles with UV fluorescent tryptophan biomolecules.…”

Section: Introductionmentioning

confidence: 99%

A fluorescent nanoprobe for single bacterium tracking: functionalization of silver nanoparticles with tryptophan to probe the nanoparticle accumulation with single cell resolution

Dojčilović

Pajović

Božanić

et al. 2016

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The investigation of the interaction of silver nanoparticles and live bacteria cells is of particular importance for understanding and controlling their bactericidal properties. In this study, the process of internalization of silver nanoparticles in Escherichia coli cells was followed by means of synchrotron excitation deep ultraviolet (DUV) fluorescence imaging. Antimicrobial nanostructures that can absorb and emit light in the UV region were prepared by functionalization of silver nanoparticles with tryptophan amino acid and used as environmentally sensitive fluorescent probes. The nanostructures were characterized by morphological (TEM) and spectroscopic methods (UV-vis, FTIR, XPS, and photoluminescence). The TEM images and the analyses of the UV-vis spectra suggested that the addition of tryptophan led to the formation of hybrid nanostructures with pronounced eccentricity and larger sizes with respect to that of the initial silver nanoparticles. The DUV imaging showed that it was possible to distinguish the fluorescent signal pertaining to silver-tryptophan nanostructures from the autofluorescence of the bacteria. The spatial resolution of the fluorescence images was 154 nm which was sufficient to perform analyses of the accumulation of the nanostructures within a single bacterium. The DUV imaging results imply that the tryptophan-functionalized silver nanoparticles interact with cell membranes via insertion of the amino acid into the phospholipid bilayer and enter the cells.

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Tryptophan-functionalized gold nanoparticles for deep UV imaging of microbial cells

Cited by 36 publications

References 25 publications

Toxicity of Food-Grade TiO2 to Commensal Intestinal and Transient Food-Borne Bacteria: New Insights Using Nano-SIMS and Synchrotron UV Fluorescence Imaging

Toxicity of Food-Grade TiO2 to Commensal Intestinal and Transient Food-Borne Bacteria: New Insights Using Nano-SIMS and Synchrotron UV Fluorescence Imaging

The Effect of Fatty Acids and BSA Purity on Synthesis and Properties of Fluorescent Gold Nanoclusters

A fluorescent nanoprobe for single bacterium tracking: functionalization of silver nanoparticles with tryptophan to probe the nanoparticle accumulation with single cell resolution

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