Inner Surface Biofilm Inactivation by Atmospheric Pressure Helium Porous Plasma Jet

We present a helium porous plasma jet based on gas diffuser, designed with the aim ofdecontaminating inner surfaces of contaminated structures, e.g., pipes. The porous plasma jet operates with three discharge modes in ambient air and inside a vessel. Its decontamination capacity is demonstrated by evaluating the inactivation efficacy of biofilm form of Pseudomonas aeruginosa, adherent to inner surface of a glass vial.Plasma treatments for 5 min with filament mode and double region helium discharge mode reduced bacterial numbers by 2.4 and 2.5 Log10CFU/ml.Plasma treatment with double region air-like discharge mode was the most effective, reducin bacterial cells by 4.5 Log10CFU/ml, which demonstrates porous plasma jet could provide an efficient approach for inner surface decontamination

PLGA-Gold Nanocomposite: Preparation and Biomedical Applications

A composite system consisting of both organic and inorganic nanoparticles is an approach to prepare a new material exhibiting “the best of both worlds”. In this review, we highlight the recent advances in the preparation and applications of poly(lactic-co-glycolic acid)-gold nanoparticles (PLGA-GNP). With its current clinically use, PLGA-based nanocarriers have promising pharmaceutical applications and can “extract and utilize” the fascinating optical and photothermal properties of encapsulated GNP. The resulting “golden polymeric nanocarrier” can be tracked, analyzed, and visualized using the encapsulated gold nanoprobes which facilitate a better understanding of the hosting nanocarrier’s pharmacokinetics and biological fate. In addition, the “golden polymeric nanocarrier” can reveal superior nanotherapeutics that combine both the photothermal effect of the encapsulated gold nanoparticles and co-loaded chemotherapeutics. To help stimulate more research on the development of nanomaterials with hybrid and exceptional properties, functionalities, and applications, this review provides recent examples with a focus on the available chemistries and the rationale behind encapsulating GNP into PLGA nanocarriers that has the potential to be translated into innovative, clinically applicable nanomedicine.A.M.A. acknowledge funding support from the University of Jordan. The APC was funded by the University of Illinois at Urbana-Champaign

Atmospheric air plasma induces increased cell aggregation during the formation of Escherichia coli biofilms

Atmospheric air plasma has previously been shown to be a novel and effective method for biofilm eradication. Here we study the effects of plasma on both microbial inactivation and induced structural modification for forming biofilms. New structures are created from aggregates of extracellular polysaccharides and dead bacterial cells, forming a protective and resilient matrix in which the remaining living cells grow and reproduce under proper growth conditions. The new colonies are found to be more resilient in this state, reducing the efficacy of subsequent plasma treatment. We verify that the observed effect is not caused by chemicals produced by plasma reactive species, but instead by the physical processes of drying and convection caused by the plasma discharge

Antimicrobial applications of atmospheric pressure non-thermal plasma

In this study, an in-house built atmospheric. pressure non-thermal plasma jet has been investigated for its potential utilisation as a new alternative antimicrobial tool for a variety of medical applications. Anti - biofilm activity of this plasma jet has been evaluated against biofilms of a selected panel of bacterial species, grown on different abiotic surfaces, where complete eradication of all tested bacterial biofilms was achieved after relatively short plasma exposures of up to 10 minutes. Multiple approaches of cell viability evaluation were adopted to show the nature, extent and distribution of the remarkable anti-biofilm activity of the plasma jet including colony counting, XTT metabolic assay, scanning electron microscopy examination and differential Live/Dead fluorescent staining followed by confocal laser scanning microscopy examination. Antibacterial efficacy of the plasma jet has also been evaluated against similar bacterial species in their planktonic mode of growth where plasma exposures even shorter than those required for biofilm eradication were sufficient to cause complete inactivation of these planktonic bacteria. Such excellent bactericidal activity resulted from the ability of plasma exposure to mediate an oxidative damage to multiple cellular targets including cellular membrane, DNA and proteins of bacterial cells. However, damage of cellular membrane and the resultant disruption of its integrity and permeability were shown to be the primary rate-determining step in the plasma mediated bacterial cell death. Furthermore, in depth investigation of the plasma- mediated bacterial destruction mechanism has been carried out to identify the plasma-produced reactive species that were responsible for mediating its bactericidal activity. Based on the findings of this study, a hypothesis was formulated to describe the mechanism of bacterial cell destruction after plasma exposure. This hypothesis assumed a two-part mechanism; one part was a rapid H20 2-dependent mechanism associated with Fenton's or Fenton's-like reaction that was catalysed by metal ions released from the bacterial cells initially damaged by another proposed H20 2 - independent mechanism.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The In Vitro Susceptibility of Biofilm Forming Medical Device Related Pathogens to Conventional Antibiotics

Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm eradication concentration (MBEC) and kill kinetics were established for vancomycin, rifampicin, trimethoprim, gentamicin, and ciprofloxacin against the biofilm forming bacteria Staphylococcus epidermidis (ATCC 35984), Staphylococcus aureus (ATCC 29213), Methicillin Resistant Staphylococcus aureus (MRSA) (ATCC 43300), Pseudomonas aeruginosa (PAO1), and Escherichia coli (NCTC 8196). MICs and MBCs were determined via broth microdilution in 96-well plates. MBECs were studied using the Calgary Biofilm Device. Values obtained were used to investigate the kill kinetics of conventional antimicrobials against a range of planktonic and biofilm microorganisms over a period of 24 hours. Planktonic kill kinetics were determined at 4xMIC and biofilm kill kinetics at relative MBECs. Susceptibility of microorganisms varied depending on antibiotic selected and phenotypic form of bacteria. Gram-positive planktonic isolates were extremely susceptible to vancomycin (highest MBC: 7.81 mg L−1: methicillin sensitive and resistant S. aureus) but no MBEC value was obtained against all biofilm pathogens tested (up to 1000 mg L−1). Both gentamicin and ciprofloxacin displayed the broadest spectrum of activity with MIC and MBCs in the mg L−1 range against all planktonic isolates tested and MBEC values obtained against all but S. epidermidis (ATCC 35984) and MRSA (ATCC 43300)