scholarly journals Hydrogen Peroxide Generation of Copper/Ascorbate Formulations on Cotton: Effect on Antibacterial and Fibroblast Activity for Wound Healing Application

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2399 ◽  
Author(s):  
J. Edwards ◽  
Nicolette Prevost ◽  
Michael Santiago ◽  
Terri von Hoven ◽  
Brian Condon ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Wound Healing ◽  
Cotton Fiber ◽  
Cotton Effect ◽  
Aqueous Environment ◽  
Amplex Red ◽  
Low Levels ◽  
Icp Analysis ◽  
Hydrogen Peroxide Generation

Greige cotton (unbleached cotton) is an intact plant fiber that retains much of the outer cotton fiber layers. These layers contain pectin, peroxidases, and trace metals that are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. When greige cotton is subjected to a nonwoven hydroentanglement process, components of the outer cotton fiber layers are retained. When hydrated, this fabric can generate H2O2 (5–50 micromolar). This range has been characterized as inducing accelerated wound healing associated with enhanced cell signaling and the proliferation of cells vital to wound restoration. On the other hand, H2O2 levels above 50 micromolar have been associated with bacteriostatic activity. Here, we report the preparation and hydrogen peroxide activity of copper/ascorbate formulations, both as adsorbed and in situ synthesized analogs on cotton. The cooper/ascorbate-cotton formulations were designed with the goal of modulating hydrogen peroxide levels within functional ranges beneficial to wound healing. The cotton/copper formulation analogs were prepared on nonwoven unbleached cotton and characterized with cotton impregnation titers of 3–14 mg copper per gram of cotton. The copper/ascorbate cotton analog formulations were characterized spectroscopically, and the copper titer was quantified with ICP analysis and probed for peroxide production through assessment with Amplex Red. All analogs demonstrated antibacterial activity. Notably, the treatment of unbleached cotton with low levels of ascorbate (~2 mg/g cotton) resulted in a 99 percent reduction in Klebsiella pneumoniae and Staphylococcus aureus. In situ synthesized copper/ascorbate nanoparticles retained activity and did not leach out upon prolonged suspension in an aqueous environment. An assessment of H2O2 effects on fibroblast proliferation are discussed in light of the copper/cotton analogs and wound healing.

scholarly journals Multienzymatic in situ hydrogen peroxide generation cascade for peroxygenase-catalysed oxyfunctionalisation reactions

2019 ◽  
Vol 74 (3-4) ◽  
pp. 101-104 ◽  
Author(s):  
Milja Pesic ◽  
Sébastien Jean-Paul Willot ◽  
Elena Fernández-Fueyo ◽  
Florian Tieves ◽  
Miguel Alcalde ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Formate Dehydrogenase ◽  
Flavin Mononucleotide ◽  
Candida Boidinii ◽  
Reaction Parameters ◽  
Old Yellow Enzyme ◽  
Hydroxylation Reaction ◽  
In Situ Generation ◽  
Hydrogen Peroxide Generation

Abstract There is an increasing interest in the application of peroxygenases in biocatalysis, because of their ability to catalyse the oxyfunctionalisation reaction in a stereoselective fashion and with high catalytic efficiencies, while using hydrogen peroxide or organic peroxides as oxidant. However, enzymes belonging to this class exhibit a very low stability in the presence of peroxides. With the aim of bypassing this fast and irreversible inactivation, we study the use of a gradual supply of hydrogen peroxide to maintain its concentration at stoichiometric levels. In this contribution, we report a multienzymatic cascade for in situ generation of hydrogen peroxide. In the first step, in the presence of NAD+ cofactor, formate dehydrogenase from Candida boidinii (FDH) catalysed the oxidation of formate yielding CO2. Reduced NADH was reoxidised by the reduction of the flavin mononucleotide cofactor bound to an old yellow enzyme homologue from Bacillus subtilis (YqjM), which subsequently reacts with molecular oxygen yielding hydrogen peroxide. Finally, this system was coupled to the hydroxylation of ethylbenzene reaction catalysed by an evolved peroxygenase from Agrocybe aegerita (rAaeUPO). Additionally, we studied the influence of different reaction parameters on the performance of the cascade with the aim of improving the turnover of the hydroxylation reaction.

Metal-free carbon nitride photocatalysis with in situ hydrogen peroxide generation for the degradation of aromatic compounds

2019 ◽  
Vol 252 ◽  
pp. 128-137 ◽  
Author(s):  
André Torres-Pinto ◽  
Maria J. Sampaio ◽  
Cláudia G. Silva ◽  
Joaquim L. Faria ◽  
Adrián M.T. Silva
Keyword(s):  
Hydrogen Peroxide ◽  
Aromatic Compounds ◽  
Carbon Nitride ◽  
Free Carbon ◽  
Metal Free ◽  
Hydrogen Peroxide Generation

scholarly journals Influence of electrode material on hydrogen peroxide generation by DC pinhole discharge

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Edita Vyhnánková ◽  
Zdenka Kozáková ◽  
František Krčma ◽  
Aleš Hrdlička
Keyword(s):  
Hydrogen Peroxide ◽  
Electrode Material ◽  
Lower Cost ◽  
Electrode Materials ◽  
Decomposition Reactions ◽  
Discharge Operation ◽  
The Difference ◽  
Icp Analysis ◽  
Hydrogen Peroxide Generation ◽  
Titanium Zinc

AbstractIn this work, several materials were studied as electrodes in a pinhole configuration of a DC plasma discharge to estimate their effect on the efficiency of the discharge, indicated by hydrogen peroxide production. Detection was carried out using a specific titanium reagent. This was combined with ICP-OES analysis of the final solutions to determine the difference between the amount of electrode material released during the discharge operation and electrolysis experiment carried out under the same conditions. It was found that from seven studied electrode materials, graphite gives the best results, while lower cost aluminum and titanium-zinc still work well. The most unsuitable materials were copper and brass; in these cases, no hydrogen peroxide was detected in the cathode part of the reactor. Results obtained by ICP analysis indicate that even in the case of brass, the absence of hydrogen peroxide is due to the presence of copper in the material. It probably affects both directly the phase of discharge creation and propagation and the decomposition reactions.

scholarly journals Distinct Redox Signalling following Macrophage Activation Influences Profibrotic Activity

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Caitlin V. Lewis ◽  
Antony Vinh ◽  
Henry Diep ◽  
Chrishan S. Samuel ◽  
Grant R. Drummond ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Macrophage Activation ◽  
M2 Macrophage ◽  
Superoxide Generation ◽  
Amplex Red ◽  
Enhanced Chemiluminescence ◽  
M1 Macrophage ◽  
Adventitial Fibroblasts ◽  
Hydrogen Peroxide Generation ◽  
M1 And M2 Macrophages

Aims. To date, the ROS-generating capacities of macrophages in different activation states have not been thoroughly compared. This study is aimed at determining the nature and levels of ROS generated following stimulation with common activators of M1 and M2 macrophages and investigating the potential for this to impact fibrosis. Results. Human primary and THP-1 macrophages were treated with IFN-γ+LPS or IL-4-activating stimuli, and mRNA expression of established M1 (CXCL11, CCR7, IL-1β) and M2 (MRC-1, CCL18, CCL22) markers was used to confirm activation. Superoxide generation was assessed by L-012-enhanced chemiluminescence and was increased in both M(IFN-γ+LPS) and M(IL-4) macrophages, as compared to unpolarised macrophages (MΦ). This signal was attenuated with NOX2 siRNA. Increased expression of the p47phox and p67phox subunits of the NOX2 oxidase complex was evident in M(IFN-γ+LPS) and M(IL-4) macrophages, respectively. Amplex Red and DCF fluorescence assays detected increased hydrogen peroxide generation following stimulation with IL-4, but not IFN-γ+LPS. Coculture with human aortic adventitial fibroblasts revealed that M(IL-4), but not M(IFN-γ+LPS), enhanced fibroblast collagen 1 protein expression. Macrophage pretreatment with the hydrogen peroxide scavenger, PEG-catalase, attenuated this effect. Conclusion. We show that superoxide generation is not only enhanced with stimuli associated with M1 macrophage activation but also with the M2 stimulus IL-4. Macrophages activated with IL-4 also exhibited enhanced hydrogen peroxide generation which in turn increased aortic fibroblast collagen production. Thus, M2 macrophage-derived ROS is identified as a potentially important contributor to aortic fibrosis.

In Situ Hydrogen Peroxide Generation for Use as a Disinfectant and as an Oxidant for Water Recovery by Aqueous Phase Catalytic Oxidation

1996 ◽  
Author(s):  
James R. Akse ◽  
James E. Atwater ◽  
Leonard J. Schussel ◽  
John O. Thompson ◽  
Frank C. Garmon ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Oxidation ◽  
Aqueous Phase ◽  
Water Recovery ◽  
Hydrogen Peroxide Generation
Sign in / Sign up

Export Citation Format

Share Document