Although selenium nanoparticles (SeNPs) have gained attention in the scientific community mostly through investigation of their anticancer activity, a great potential of this nanomaterial was ...recognized recently regarding its antimicrobial activity. The particle form, size, and surface chemistry have been recognized as crucial parameters determining the interaction of nanomaterials with biological entities. Furthermore, considering a narrow boundary between beneficial and toxic effects for selenium per se, it is clear that investigations of biomedical applications of SeNPs are very demanding and must be done with great precautions. The goal of this work is to evaluate the effects of SeNPs surface chemistry and structure on antimicrobial activity against several common bacterial strains, including
(ATCC 6538),
(ATCC 29212),
(ATCC 6633), and
(ATCC 9341), as well as
(ATCC 8739),
Abony (NCTC 6017),
(NCIMB 9111) and
(ATCC 9027), and the standard yeast strain
(ATCC 10231). Three types of SeNPs were synthesized by chemical reduction approach using different stabilizers and reducing agents: (i) bovine serum albumin (BSA) + ascorbic acid, (ii) chitosan + ascorbic acid, and (iii) with glucose. A thorough physicochemical characterization of the obtained SeNPs was performed to determine the effects of varying synthesis parameters on their morphology, size, structure, and surface chemistry. All SeNPs were amorphous, with spherical morphology and size in the range 70-300 nm. However, the SeNPs obtained under different synthesis conditions, i.e. by using different stabilizers as well as reducing agents, exhibited different antimicrobial activity as well as cytotoxicity which are crucial for their applications. In this paper, the antimicrobial screening of the selected systems is presented, which was determined by the broth microdilution method, and inhibitory influence on the production of monomicrobial and dual-species biofilm was evaluated. The potential mechanism of action of different systems is proposed. Additionally, the cytotoxicity of SeNPs was examined on the MRC-5 cell line, in the same concentration interval as for antimicrobial testing. It was shown that formulation SeNPs-BSA expressed a significantly lower cytotoxic effect than the other two formulations.
Aims
To investigate the synergistic activity of colistin and selenium nanoparticles (SeNPs) against pandrug‐resistant (PDR) Ac. baumannii.
Methods and Results
Chequerboard and time‐kill assays were ...employed to explore the potential synergistic interactions between colistin and SeNPs against Ac. baumannii isolates (8), previously determined as colistin‐resistant (MIC range 16–256 μg ml−1). Also, whole‐genome sequencing (WGS) and gene expression analyses were used to elucidate the mechanisms of colistin resistance. Exceptionally strong synergistic activity (FICI range 0.004–0.035) of colistin and SeNPs against colistin‐resistant isolates was revealed. Colistin (0.5 or 1 μg ml−1) used in combination with SeNPs (0.5 μg ml−1) was able to reduce initial inoculum during the first 4 h of incubation, in contrast to colistin (0.5, 1 or 2 μg ml−1) alone.
Conclusions
These findings propose colistin/SeNPs combination as a new option to fight PDR Ac. baumannii, the therapeutic possibilities of which should be proved in future in vivo studies.
Significance and Impact of Study
Here we present the first evidence of synergy between colistin and selenium compounds against bacteria in general. Also, WGS and gene expression analyses provide some new insights into Ac. baumannii colistin resistance mechanisms.
Recently, many studies have shown various beneficial effects of polyphenol resveratrol (Res) on human health. The most important of these effects include cardioprotective, neuroprotective, ...anti-cancer, anti-inflammatory, osteoinductive, and anti-microbial effects. Resveratrol has cis and trans isoforms, with the trans isoform being more stable and biologically active. Despite the results of in vitro experiments, resveratrol has limited potential for application in vivo due to its poor water solubility, sensitivity to oxygen, light, and heat, rapid metabolism, and therefore low bioavailability. The possible solution to overcome these limitations could be the synthesis of resveratrol in nanoparticle form. Accordingly, in this study, we have developed a simple, green solvent/non-solvent physicochemical method to synthesize stable, uniform, carrier-free resveratrol nanobelt-like particles (ResNPs) for applications in tissue engineering. UV–visible spectroscopy (UV-Vis) was used to identify the trans isoform of ResNPs which remained stable for at least 63 days. The additional qualitative analysis was performed by Fourier transform infrared spectroscopy (FTIR), while X-ray diffraction (XRD) determined the monoclinic structure of resveratrol with a significant difference in the intensity of diffraction peaks between commercial and nano-belt form. The morphology of ResNPs was evaluated by optical microscopy and field-emission scanning electron microscope (FE-SEM) that revealed a uniform nanobelt-like structure with an individual thickness of less than 1 μm. Bioactivity was confirmed using Artemia salina in vivo toxicity assay, while 2,2–diphenyl-1-picrylhydrazylhydrate (DPPH) reduction assay showed the good antioxidative potential of concentrations of 100 μg/ml and lower. Microdilution assay on several reference strains and clinical isolates showed promising antibacterial potential on Staphylococci, with minimal inhibitory concentration (MIC) being 800 μg/ml. Bioactive glass-based scaffolds were coated with ResNPs and characterized to confirm coating potential. All of the above make these particles a promising bioactive, easy-to-handle component in various biomaterial formulations.
Graphical Abstract
Silver nanoparticles (AgNps) were prepared by modified chemical reduction with poly (α, γ, l-glutamic acid) (PGA) as capping agent. These Ag/PGA nanoparticles (AgNpPGAs) were highly stable over long ...periods of time without signs of precipitation. In addition to obtaining stable AgNpPGAs, a further aim was to examine their encapsulation in the poly(L-lactide-co-glycolide) (PLGA) polymer matrix. The current interest of polymer-AgNps in biomedical applications is because a versatile system must have antimicrobial activity upon target contact, without the release of toxic biocides. The synthesis of these PLGA/AgNpPGAs used physicochemical methods with solvent/non-solvent systems. Degradation of these PLGA/AgNpPGAs and the release rate of their AgNPs were studied in physiological solution over three months. The antimicrobial activity of the samples was investigated towards six laboratory control strains from the American Type Culture Collection (ATCC) and one clinical isolate methicillin-resistant Staphylococcus aureus strain by the broth microdilution method and the results showed superior and extended activity of PLGA/AgNpPGAs. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated good biocompatibility of these PLGA/AgNpPGAs. The formation of intracellular reactive oxygen species was measured spectrophotometrically using a fluorescent probe, which showed that these PLGA/AgNpPGAs are not inducers of such species. The samples were characterized by UV–VIS spectrometry, X-ray diffraction, zeta potential measurements, field-emission scanning electron microscopy, and transmission electron microscopy.
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In this work, we synthesized a new composite material comprised of previously formulated resveratrol nanobelt-like particles (ResNPs) and selenium nanoparticles (SeNPs), namely ResSeNPs. ...Characterization was provided by FESEM and optical microscopy, as well as by UV-Vis and FTIR spectroscopy, the last showing hydrogen bonds between ResNPs and SeNPs. DPPH, TBA, and FRAP assays showed excellent antioxidative abilities with ResNPs and SeNPs contributing mainly to lipid peroxidation inhibition and reducing/scavenging activity, respectively. The antibacterial effect against common medicinal implant colonizers pointed to notably higher activity against
isolates (minimal inhibitory concentrations 0.75-1.5%) compared to tested gram-negative species (
and
). Antibiofilm activity against
,
, and
determined in a crystal violet assay was promising (up to 69%), but monitoring of selected biofilm-related gene expression (
A and
D) indicated the necessity of the involvement of a larger number of genes in the analysis in order to further establish the underlying mechanism. Although biocompatibility screening showed some cytotoxicity and genotoxicity in MTT and alkaline comet assays, respectively, it is important to note that active antioxidative and antibacterial/antibiofilm concentrations were non-cytotoxic and non-genotoxic in normal MRC-5 cells. These results encourage further composite improvements and investigation in order to adapt it for specific biomedical purposes.
Multidrug-resistant bacterial strains represent an emerging global health threat and a great obstacle for bone tissue engineering. One of the major components of the extracellular matrix of the bone ...is a collagen protein, while selenium is an element that has antimicrobial potential, and is also important for bone metabolism and bone health. Here we represent the incorporation of selenium nanoparticles (SeNPs) synthesized by the green chemical reduction method into collagen gels to produce a composite material, collagen/SeNPs, with antimicrobial properties. The samples were comprehensively characterized by zeta potential measurements, dynamic light scattering inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), optical microscopy, field-emission scanning electron microscopy (FE-SEM), and differential scanning calorimetry The cytotoxicity of the SeNPS, as well as collagen/SeNPs, was tested on the MRC-5 cells. It was revealed that collagen/SeNPS expressed a lower cytotoxic effect. Collagen/SeNPs showed significant antibacterial activity against all tested Gram-positive strains, the major causative agents of orthopedic infections as well as Candida albicans. Furthermore, three-dimensional β-tricalcium phosphate (3D-TCP) scaffolds were fabricated by a well-established 3D printing (lithography) method, and afterward preliminary coated by newly-synthesized SeNPs or collagen/SeNPs. In addition, uncoated 3D-TCP scaffolds as well as coated by collagen/SeNPs were subjected to biofilm formation. The production of Staphylococcus aureus biofilm on coated scaffolds by collagen/SeNPs was significantly reduced compared to the uncoated ones.
Safe-by-design gelatin-modified zinc oxide nanoparticles Janićijević, Željko; Stanković, Ana; Žegura, Bojana ...
Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology,
09/2021, Letnik:
23, Številka:
9
Journal Article
Odprti dostop
We report an innovative low-cost wet precipitation synthesis method for gelatin-modified zinc oxide nanoparticles (GM ZnO NPs) at the interface between the gelatin hydrogel and aqueous electrolyte. ...Diffusion of ammonia through the hydrogel matrices with different gelatin contents induced precipitation of the product in contact with the surface of the aqueous solution of zinc ions. The obtained precipitate was subjected to thermal treatment to partially decompose the adsorbed gelatin in the NP structure. Physicochemical properties of obtained GM ZnO NPs were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential thermal analysis (DTA), thermogravimetry (TG), photon correlation spectroscopy (PCS), zeta potential measurements, and inductively coupled plasma-mass spectrometry (ICP-MS). The estimated mean crystallite size of GM ZnO NP powders was in the range from 5.8 to 12.1 nm. The synthesized NPs exhibited nanosheet morphology and arranged into flake-like aggregates. The toxic potential was investigated in vitro in human hepatocellular carcinoma cell line HepG2. The thiazolyl blue tetrazolium bromide (MTS) assay was used to assess cell viability, 2′,7′-dichlor-fluorescein-diacetate (DCFH-DA) assay to examine the formation of intracellular reactive oxygen species (ROS), and comet assay to evaluate the genotoxic response. GM ZnO NPs slightly reduced HepG2 cell viability, did not induce ROS formation, and showed low genotoxic potential at very high doses (100 µg mL
−1
). ZnO NPs fabricated and modified using the proposed methodology deserve further study as potential candidates for antibacterial agents or dietary supplements with low overall toxicity.
Graphical abstract
•Magnetic iron oxide nanocrystals are synthesized via a simple solvothermal approach.•Use of cheap and non-toxic chemicals: iron(III) chloride, glucose and oleic acid.•Synthesized nanocrystals show a ...low degree of polydispersity and sizes down to 5nm.•Produced hydrophobic nanocrystals are transformed to hydrophilic.•Nanocrystals are immobilised to a poly(l-lactide)/polyethileneimine polymeric matrix.
We report a simple and green procedure for the preparation of magnetic iron oxide nanocrystals via solvothermal synthesis. The nanocrystal synthesis was carried out under mild conditions in the water–ethanol–oleic acid solvent system with the use of the oleate anion as a surface modifier of nanocrystals and glucose as a reducing agent. Specific conditions for homogenous precipitation achieved in such a reaction system lead to the formation of uniform high-quality nanocrystals down to 5nm in diameter. The obtained hydrophobic nanocrystals can easily be converted to hydrophilic magnetic nanoparticles by being immobilized in a poly(l-lactide)–polyethyleneimine polymeric matrix. These hybrid nano-constructs may find various biomedical applications, such as magnetic separation, gene transfection and/or magnetic resonance imaging.
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