Delivery and quantification of hydrogen peroxide generated via cold atmospheric pressure plasma through biological material

The ability of plasma-generated hydrogen peroxide (H 2O 2) to traverse bacterial biofilms and the subsequent fate of the generated H 2O 2 has been investigated. An in vitro model, comprising a nanoporous membrane impregnated with artificial wound fluid and biofilms of varying maturity was treated with a helium-driven, cold atmospheric pressure plasma (CAP) jet. The concentration of H 2O 2 generated below the biofilms was quantified. The results showed that the plasma-generated H 2O 2 interacted significantly with the biofilm, thus exhibiting a reduction in concentration across the underlying nanoporous membrane. Biofilm maturity exhibited a significant effect on the penetration depth of H 2O 2, suggesting that well established, multilayer biofilms are likely to offer a shielding effect with respect to cells located in the lower layers of the biofilm, thus rendering them less susceptible to plasma disinfection. This may prove clinically significant in the plasma treatment of chronic, deep tissue infections such as diabetic and venous leg ulcers. Our results are discussed in the context of plasma-biofilm interactions, with respect to the fate of the longer lived reactive species generated by CAP, such as H 2O

A small-molecular inhibitor against Proteus mirabilis urease to treat catheter-associated urinary tract infections

Infection and blockage of indwelling urinary catheters is significant owing to its high incidence rate and severe medical consequences. Bacterial enzymes are employed as targets for small molecular intervention in human bacterial infections. Urease is a metalloenzyme known to play a crucial role in the pathogenesis and virulence of catheter-associated Proteus mirabilis infection. Targeting urease as a therapeutic candidate facilitates the disarming of bacterial virulence without affecting bacterial fitness, thereby limiting the selective pressure placed on the invading population and lowering the rate at which it will acquire resistance. We describe the design, synthesis, and in vitro evaluation of the small molecular enzyme inhibitor 2-mercaptoacetamide (2-MA), which can prevent encrustation and blockage of urinary catheters in a physiologically representative in vitro model of the catheterized urinary tract. 2-MA is a structural analogue of urea, showing promising competitive activity against urease. In silico docking experiments demonstrated 2-MA’s competitive inhibition, whilst further quantum level modelling suggests two possible binding mechanisms

Delivery and quantification of hydrogen peroxide generated via cold atmospheric pressure plasma through biological material

The ability of plasma-generated hydrogen peroxide (H2O2) to traverse bacterial biofilms and the subsequent fate of the generated H2O2 has been investigated. An in vitro model, comprising a nanoporous membrane impregnated with artificial wound fluid and biofilms of varying maturity was treated with a helium-driven, cold atmospheric pressure plasma (CAP) jet. The concentration of H2O2 generated below the biofilms was quantified. The results showed that the plasma-generated H2O2 interacted significantly with the biofilm, thus exhibiting a reduction in concentration across the underlying nanoporous membrane. Biofilm maturity exhibited a significant effect on the penetration depth of H2O2, suggesting that well established, multilayer biofilms are likely to offer a shielding effect with respect to cells located in the lower layers of the biofilm, thus rendering them less susceptible to plasma disinfection. This may prove clinically significant in the plasma treatment of chronic, deep tissue infections such as diabetic and venous leg ulcers. Our results are discussed in the context of plasma-biofilm interactions, with respect to the fate of the longer lived reactive species generated by CAP, such as H2O2