Evaluation of Cellular and Systemic Toxicity of Dielectric Barrier Discharge Plasma-Treated N-Acetylcysteine as Potential Antimicrobial Catheter Lock Solution

Intravenous catheter-related bloodstream infections are a cause of remarkable problems. Catheter lock solutions are used to keep catheter patency and prevent catheter-related bloodstream infections. The leakage of catheter lock solution to the bloodstream raises toxicity concerns. Plasma-treated liquids carry the potential to act as catheter lock solutions by virtue of their strong antimicrobial effects. The present study investigates the tolerance of the proposed solution in vitro and in vivo. N-acetylcysteine (NAC) solution was treated with atmospheric-air DBD plasma and antimicrobial assays were performed. The cytotoxicity of the plasma-treated NAC solution was evaluated on an EA.hy926 cell line. Intravenous administration of plasma-treated NAC solution in different doses was given to Sprague Dawley rats. One week after infusion with plasma-treated NAC solution, first, the blood samples were collected, and then liver, kidney, tail vein, heart, and lung tissue samples were collected from euthanized rats for histopathological examination. The cytotoxicity of plasma-treated NAC solution depended on plasma treatment time, contact time, and cell number. A strong antimicrobial effect with no cytotoxicity of plasma-treated NAC solution was observed in endothelial cells. Based on blood tests and histopathological examination, no signs of systemic toxicity were observed that can be correlated to the plasma-treated-NAC solution. This solution has the potential to be used as a catheter lock solution with strong antimicrobial properties, keeping catheter patency

Deionized water can substitute common bleaching agents for nonvital tooth bleaching when treated with non-thermal atmospheric plasma

WOS: 000462712900015PubMed ID: 30713266The bleaching efficacy of common bleaching agents and deionized water treated with non-thermal atmospheric pressure plasma in the pulp chamber for nonvital tooth bleaching was evaluated. A total of 120 extracted human maxillary first incisors were stained using human blood. Teeth were randomly divided into eight groups (n = 15). In the first four groups, teeth were bleached using 35% hydrogen peroxide gel, 37% carbamide peroxide gel, 2:1 (w/v) sodium perborate paste, and deionized water for 30 min. In the remaining groups, bleaching agents were treated with non-thermal atmospheric plasma for 5 min inside the pulp chamber. Overall color changes (Delta E) were determined using Commission Internationale de L'Eclairage Lab Colour System. The plasma-assisted tooth bleaching has not increased tooth temperature beyond 37 degrees C. Bleaching efficacies of bleaching agents were significantly improved when treated with non-thermal atmospheric plasma compared to their application (P < 0.05). A remarkable bleaching effect was obtained when bleaching agents were substituted with water and when treated with non-thermal atmospheric plasma. Non-thermal atmospheric plasma treatment could be a novel tool for activation of bleaching agents in the pulp chamber for nonvital tooth bleaching procedure. Moreover, water could be used as a novel bleaching agent when treated with the non-thermal atmospheric plasma to eliminate possible risks which might arise from peroxide-containing agents

Evaluation of Cellular and Systemic Toxicity of Dielectric Barrier Discharge Plasma-Treated <i>N</i>-Acetylcysteine as Potential Antimicrobial Catheter Lock Solution

Intravenous catheter-related bloodstream infections are a cause of remarkable problems. Catheter lock solutions are used to keep catheter patency and prevent catheter-related bloodstream infections. The leakage of catheter lock solution to the bloodstream raises toxicity concerns. Plasma-treated liquids carry the potential to act as catheter lock solutions by virtue of their strong antimicrobial effects. The present study investigates the tolerance of the proposed solution in vitro and in vivo. N-acetylcysteine (NAC) solution was treated with atmospheric-air DBD plasma and antimicrobial assays were performed. The cytotoxicity of the plasma-treated NAC solution was evaluated on an EA.hy926 cell line. Intravenous administration of plasma-treated NAC solution in different doses was given to Sprague Dawley rats. One week after infusion with plasma-treated NAC solution, first, the blood samples were collected, and then liver, kidney, tail vein, heart, and lung tissue samples were collected from euthanized rats for histopathological examination. The cytotoxicity of plasma-treated NAC solution depended on plasma treatment time, contact time, and cell number. A strong antimicrobial effect with no cytotoxicity of plasma-treated NAC solution was observed in endothelial cells. Based on blood tests and histopathological examination, no signs of systemic toxicity were observed that can be correlated to the plasma-treated-NAC solution. This solution has the potential to be used as a catheter lock solution with strong antimicrobial properties, keeping catheter patency

Calcium Binding-Mediated Sustained Release of Minocycline from Hydrophilic Multilayer Coatings Targeting Infection and Inflammation

<div><p>Infection and inflammation are common complications that seriously affect the functionality and longevity of implanted medical implants. Systemic administration of antibiotics and anti-inflammatory drugs often cannot achieve sufficient local concentration to be effective, and elicits serious side effects. Local delivery of therapeutics from drug-eluting coatings presents a promising solution. However, hydrophobic and thick coatings are commonly used to ensure sufficient drug loading and sustained release, which may limit tissue integration and tissue device communications. A calcium-mediated drug delivery mechanism was developed and characterized in this study. This novel mechanism allows controlled, sustained release of minocycline, an effective antibiotic and anti-inflammatory drug, from nanoscale thin hydrophilic polyelectrolyte multilayers for over 35 days at physiologically relevant concentrations. pH-responsive minocycline release was observed as the chelation between minocycline and Ca²⁺ is less stable at acidic pH, enabling ‘smart’ drug delivery in response to infection and/or inflammation-induced tissue acidosis. The release kinetics of minocycline can be controlled by varying initial loading, Ca²⁺ concentration, and Ca²⁺ incorporation into different layers, enabling facile development of implant coatings with versatile release kinetics. This drug delivery platform can potentially be used for releasing any drug that has high Ca²⁺ binding affinity, enabling its use in a variety of biomedical applications.</p></div

Nonthermal Dielectric-Barrier Discharge Plasma-Induced Inactivation Involves Oxidative DNA Damage and Membrane Lipid Peroxidation in Escherichia coli▿

Oxidative stress leads to membrane lipid peroxidation, which yields products causing variable degrees of detrimental oxidative modifications in cells. Reactive oxygen species (ROS) are the key regulators in this process and induce lipid peroxidation in Escherichia coli. Application of nonthermal (cold) plasma is increasingly used for inactivation of surface contaminants. Recently, we reported a successful application of nonthermal plasma, using a floating-electrode dielectric-barrier discharge (FE-DBD) technique for rapid inactivation of bacterial contaminants in normal atmospheric air (S. G. Joshi et al., Am. J. Infect. Control 38:293-301, 2010). In the present report, we demonstrate that FE-DBD plasma-mediated inactivation involves membrane lipid peroxidation in E. coli. Dose-dependent ROS, such as singlet oxygen and hydrogen peroxide-like species generated during plasma-induced oxidative stress, were responsible for membrane lipid peroxidation, and ROS scavengers, such as α-tocopherol (vitamin E), were able to significantly inhibit the extent of lipid peroxidation and oxidative DNA damage. These findings indicate that this is a major mechanism involved in FE-DBD plasma-mediated inactivation of bacteria

Mechanism schematic and growth of LbL assembly.

<p>(A) Schematic illustrating the mechnism of MH incorporation and LbL assembly. (B) UV absorbance of MH during DS/MH LbL assembly. (C) UV absorbance of MH during DS/MH/GA LbL assembly. *, <i>P</i><0.05 compared with (DS+Ca²⁺/MH/GA) and (DS+Ca²⁺/MH+Ca²⁺/GA) LbL films. (D) Fluorescent intensity of FITC-GA during DS/MH/GA LbL assembly. (E) Film thickness of as a function of the number of trilayers deposited on silicon substrates. Data shown are average ±STD (n = 3).</p

Effect of Ca²⁺ incorporation on MH release from (DS+Ca²⁺/MH+Ca²⁺/GA+Ca²⁺)₈ LbL films.

<p>Data shown are average ±STD (n = 3).</p

The anti-biofilm activity of (DS+Ca²⁺/MH+Ca²⁺/GA+Ca²⁺)₈ LbL film.

<p>(A) XTT assays to detect surviving bacteria demonstrate inactivation of bacteria in biofilms as a result of MH release from coatings. Significant anti-biofilm activity was observed in the wells coated with films containing MH. *, <i>P</i><0.05 compared with uncoated control (polystyrene); +, <i>P</i><0.05 compared with coatings without MH. Data shown are average ±STD (n = 4). (B) Fluorescent images of <i>A. baumannii</i> from ATCC and clinical isolate cultured on uncoated polystyrene, coatings with and without MH. The cells were stained with “live” SYTO 9 stain (green) and “dead” propidium iodide stain (red). Biofilm formation was eliminated on coatings with MH. Scale bar  = 10 µm.</p