Ionic liquids as capping agents of silver nanoparticles. Part II: Antimicrobial and cytotoxic study (original) (raw)
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Iranian endodontic journal, 2017
The antibacterial efficacy and toxicity of silver nanoparticles (AgNPs) depends on their physicochemical properties including size, shape, surface charge and surface coatings. The Objectives of this study were: i) To synthesize and characterize positively charged AgNPs coated by different ionic-liquids with different alkyl chain lengths, ii) To evaluate the antimicrobial activity of these nanoparticles against Enterococcus faecalis compared to sodium hypochlorite (NaOCl) and chlorhexidine (CHX), iii) To compare the cytocompatibility of these solutions against L929 mouse fibroblasts. AgNPs with positive surface charges capped by two different ionic liquids [imidazolium (Im) and pyridinium (Py)] with two alkyl chain lengths (C12 and C18) were synthesized. Im and Py were also tested as control groups. The characterization revealed synthesis of spherical NPs in the size range of 6.7-18.5 nm with a surface charge ranging from +25 to +58 mV. To standardize the comparisons, the surface cha...
Journal of Nanoparticle Research, 2015
Recently, ionic liquids have been used as dispersing agents for silver nanoparticle (AgNP) preparation. In this paper, we have shown a simple method to prepare AgNP in aqueous media using an ionic liquid called hexadecylpyridinium salicylate (HDPSal) as dispersing agent. The dispersions were produced by the chemical reduction of silver ions in aqueous media with different concentrations of HDPSal and tetrabutylammonium borohydride as reducing agent. The UV-Visible electronic spectra showed the characteristic plasmonic resonance band around 420 nm, confirming the formation of AgNPs. The TEM images confirmed the formation of spherical particles with diameters lower than 10 nm. The charge of these particles was determined by Zeta potential and they were around ?50 mV, indicating that the HDP cations are surrounding the AgNPs, avoiding their agglomeration. Most of the dispersions remained stable for at least 1 month. Microbiological assays showed that the combination of AgNP with HDPSal results in wider range of antimicrobial effect.
International Journal of Sciences
The formation of monometallic silver and bimetallic copper-silver nanoparticles in 1-butyl-3methylimidazolium methanesulfonate ionic liquid, through chemical reduction is reported. The synthesized particles were characterized using SEM/EDX, UV-vis, and FTIR spectroscopy. UV-vis and FTIR revealed the formation of nanoparticles with active components being adsorbed on the surface of the particles, as stabilizers. SEM revealed uniformed microspheres and microcubes for AgNPs and AgCuNPs, respectively. On the bactericidal and fungicidal activity of AgNPs and AgCuNPs against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebseilla pneumonia (bacteria) and Candidaalbicans (fungus), we observed that AgNPs inhibited Pseudomonas aeruginosa (23 mm) and Candida albicans (29 mm) higher than the bimetallic particles and the antibiotics used as control. It is interesting to note that AgCuNPs inhibited Staphylococcus aureus (21 mm) better than AgNPs (15 mm) indicative of the synergistic effect of two metals. Evaluation of Antimicrobial Activity of Ionic Liquid-Assisted Synthesis of Monometallic Silver and Bimetallic Copper-silver Nanoparticles http://www.ijSciences.com Volume 7-May 2018 (05)
Antibacterial activity and toxicity of silver – nanosilver versus ionic silver
Journal of Physics: Conference Series, 2011
The in vitro study of antibacterial activity of silver nanoparticles (NPs), prepared via modified Tollens process, revealed high antibacterial activity even at very low concentrations around several units of mg/L. These concentrations are comparable with concentrations of ionic silver revealing same antibacterial effect. However, such low concentrations of silver NPs did not show acute cytotoxicity to mammalian cells-this occurs at concentrations higher than 60 mg/L of silver, while the cytotoxic level of ionic silver is much more lower (approx. 1 mg/L). Moreover, the silver NPs exhibit lower acute ecotoxicity against the eukaryotic organisms such as Paramecium caudatum, Monoraphidium sp. and D. melanogaster. The silver NPs are toxic to these organisms at the concentrations higher than 30 mg/L of silver. On contrary, ionic silver retains its cytoxicity and ecotoxicity even at the concentration equal to 1 mg/L. The performed experiments demonstrate significantly lower toxicity of silver NPs against the eukaryotic organisms than against the prokaryotic organisms.
Synthesis and characterization of silver and gold nanoparticles in ionic liquid
2009
Silver and gold nanoparticles were synthesized using an aqueous extract of the seaweed Turbinaria conoides and their antibiofilm activity against marine biofilm forming bacteria is reported here. The UV-Vis spectra showed the characteristics SPR absorption band for Ag NPs at 421 and for Au NPs at 538 nm. Further, the synthesized nanoparticles were characterized using FT-IR, XRD, FESEM, EDX, and HRTEM analysis. Spherical and triangular nanostructures of the Ag and Au nanoparticles were observed between the size ranges of 2-17 nm and 2-19 nm, respectively. The synthesized Ag NPs are efficient in controlling the bacterial biofilm formation; however, Au NPs did not show any remarkable antibiofilm activity. The maximum zone of inhibition was recorded against E. coli (17.6 ± 0.42 mm), followed by Salmonella sp., S. liquefaciens, and A. hydrophila. The macrotube dilution method inferred the MIC (20-40 L mL −1 ) and MBC (40-60 L mL −1 ) of Ag NPs. The CLSM images clearly showed the weak adherence and disintegrating biofilm formation of marine biofilm bacterial strains treated with Ag NPs. The Artemia cytotoxicity assay recorded the LC 50 value of 88.914 ± 5.04 L mL −1 . Thus the present study proved the efficiency of Ag NPs as a potent antimicrofouling agent and became the future perspective for the possible usage in the biofouling related issues in the aquaculture installations and other marine systems.
International Endodontic Journal, 2014
charged imidazolium-based ionic liquid-protected silver nanoparticles: a promising disinfectant in root canal treatment. International Endodontic Journal. Aim To synthesize and characterize silver nanoparticles (Ag NPs) with different surface charges in order to evaluate their cytotoxicity and antibacterial activity in the absence and presence of dentine compared with NaOCl and CHX. Methodology Ag NPs with positive, negative and neutral surface charges were synthesized and characterized. The first phase of the experiment determined the minimum inhibitory concentrations (MICs) of NPs against planktonic E. faecalis and compared them with that of NaOCl and CHX. The second phase tested the elimination of E. faecalis at different contact times (5, 20 and 60 min and 4 and 24 h), and the role of dentine in their inactivation was assessed. In the third phase, the most effective Ag NP solution was selected for cytocompatibility assessment. An MTT-based cytotoxicity assay was used to evaluate the cytotoxicity of the selected NP solution in different concentrations on L929 fibroblasts compared to that of 2.5% NaOCl and 0.2% CHX. Student's t-test and repeated measures MANOVA approach were used for statistical analyses. Results The characterization revealed synthesis of colloidal NPs in the size range of 5-10 nm in diameter. The results indicated that Ag NP with a positive surface charge had the smallest MIC against planktonic E. faecalis, and it was active in very lower concentrations compared to NaOCl, CHX and the other tested AgNPs. Positive-charged Ag NPs at 5.7 9 10 À10 mol L À1 completely prevented the growth of E. faecalis after 5 min of contact time, a finding comparable to 0.025% NaOCl. Dentine powder had variable inhibitory effects on all tested materials after 1 h incubation period, but after 24 h, NaOCl and the positive-charged Ag NPs were not inhibited by dentine at any concentration used. CHX was the most and the positively charged Ag NP solution was the least toxic solutions to L929 fibroblasts (P < 0.001). Conclusions Ag NP surface charge was important in bactericidal efficacy against E. faecalis. The positively charged imidazolium-based ionic liquidprotected Ag NPs showed promising antibacterial results against E. faecalis and exhibited a high level of cytocompatibility to L929 cells.
ACS Applied Materials & Interfaces, 2012
We present a new approach for fabricating robust, regenerable antimicrobial coatings containing an ionic liquid (IL) phase incorporating silver nanoparticles (AgNPs) as a reservoir for Ag 0 /Ag + species within sol−gel-derived nanocomposite films integrating organosilicate nanoparticles. The IL serves as an ultralow volatility (vacuum-compatible) liquid target, allowing for the direct deposition and dispersion of a high-density AgNP "ionosol" following conventional sputtering techniques. Two like-anion ILs were investigated in this work: methyltrioctylammonium bis(trifluoromethylsulfonyl)imide, [N 8881 ][Tf 2 N], and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [emim][Tf 2 N]. Silver ionosols derived from these two ILs were incorporated into silica-based sol−gel films and the resultant antimicrobial activity evaluated against Pseudomonas aeruginosa bacteria. Imaging of the surface morphologies of the as-prepared films established a link between an open macroporous film architecture and the observation of high activity. Nanocomposites based on [N 8881 ][Tf 2 N] displayed excellent antimicrobial activity against P. aeruginosa over multiple cycles, reducing cell viability by 6 log units within 4 h of contact. Surprisingly, similar films prepared from [emim][Tf 2 N] presented negligible antimicrobial activity, an observation we attribute to the differing abilities of these IL cations to infiltrate the cell wall, regulating the influx of silver ions to the bacterium's interior.
We report here a systematic study of the antibacterial behavior of silver nanoparticles coated with fatty acids (oleic: AgNP-O, linoleic: AgNP-L, and palmitic acids: AgNP-P) in water. We have found remarkable differences in their capability to penetrate bacteria cell over a broader range of particle size of *4–96 nm compared to previously reported work, and a variable toxicity depending on the particles size. Our results indicate that silver nanoparticles stabilized with oleic acid showed clear advantages in antibacterial activity, penetration inside the bacteria cells, cytotoxicity, time effectiveness, efficiency, and stability against light.