In a previous communication, we reported a new method of synthesis of stable metallic copper nanoparticles (Cu-NPs), which had high potency for bacterial cell filamentation and cell killing. The present study deals with the mechanism of filament formation and antibacterial roles of Cu-NPs in E. coli cells. Our results demonstrate that NP-mediated dissipation of cell membrane potential was the probable reason for the formation of cell filaments. On the other hand, Cu-NPs were found to cause multiple toxic effects such as generation of reactive oxygen species, lipid peroxidation, protein oxidation and DNA degradation in E. coli cells. In vitro interaction between plasmid pUC19 DNA and Cu-NPs showed that the degradation of DNA was highly inhibited in the presence of the divalent metal ion chelator EDTA, which indicated a positive role of Cu(2+) ions in the degradation process. Moreover, the fast destabilization, i.e. the reduction in size, of NPs in the presence of EDTA led us to propose that the nascent Cu ions liberated from the NP surface were responsible for higher reactivity of the Cu-NPs than the equivalent amount of its precursor CuCl2; the nascent ions were generated from the oxidation of metallic NPs when they were in the vicinity of agents, namely cells, biomolecules or medium components, to be reduced simultaneously.

https://iopscience.iop.org/article/10.1088/0957-4484/25/13/135101/pdf

Mechanism of antibacterial activity of copper nanoparticles.

Wound healing is an intricate process that requires complex coordination between many cells and an appropriate extracellular microenvironment Chronic wounds often suffer from high protease activity, persistent infection, excess inflammation, and hypoxia While there has been intense investigation to find new methods to improve cutaneous wound care; the management of chronic wounds, burns, and skin wound infection remain challenging clinical problems Ideally, advanced wound dressings can provide enhanced healing and bridge the gaps in the healing processes that prevent chronic wounds from healing These technologies have great potential for improving outcomes in patients with poorly healing wounds but face significant barriers in addressing the heterogeneity and clinical complexity of chronic or severe wounds Active wound dressings aim to enhance the natural healing process and work to counter many aspects that plague poorly healing wounds including excessive inflammation, ischemia, scarring and wound infection This review paper discusses recent advances in the development of biomaterials and nanoparticle therapeutics to enhance wound healing In particular, this review focuses on the novel cutaneous wound treatments that have undergone significant preclinical development or currently used in clinical practice

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Biomaterials and Nanotherapeutics for Enhancing Skin Wound Healing.

Chitosan Based Metallic Nanocomposite Scaffolds as Antimicrobial Wound Dressings

Chitosan-based copper nanocomposite accelerates healing in excision wound model in rats.

Mercaptocarboxylic acids with different carbon chain lengths were used for stabilizing uniform 15 nm copper nanoparticles. The effects of surface chemistry such as ligand type and surface oxidation on the reactive oxygen species (ROS) generated by the copper nanoparticles were examined. Transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), UV-vis spectroscopy, and an acellular ROS assay show that ROS generation is closely related to the surface oxidation of copper nanoparticles. It was found that the copper nanoparticles with longer chain ligands had surfaces that were better protected from oxidation and a corresponding lower ROS generating capacity than did particles with shorter chain ligands. Conversely, the copper nanoparticles with greater surface oxidation also had higher ROS generating capacity.

/pdf/effects-of-surface-chemistry-on-the-generation-of-reactive-54jzfcvmmj.pdf

Effects of surface chemistry on the generation of reactive oxygen species by copper nanoparticles.

Results of a study on the wound-healing potential and physicochemical characteristics of copper nanoparticles prepared by high-temperature condensation and modified with a variety of agents (including oxygen, water vapors, and air) are reported. The modification of copper nanoparticles under monitored conditions guarantees the synthesis of particle species differing in size, phase composition, thickness, and composition of the oxide layer. Modified copper nanoparticles in the form of an ointment showed wound-healing behavior that differs in effectiveness depending on their physicochemical parameters. Nanoparticles of copper oxide (sample 7) (modified with air), with a particle size of 119 nm and crystalline copper content of ∼0.5%, and copper nanoparticles (sample 2) (modified with oxygen), with a particle size of 103 nm and crystalline copper content of 96%, demonstrated the maximum specific rate of wound adhesion.

Wound-healing properties of copper nanoparticles as a function of physicochemical parameters

Comparative study of chitosan wound healing properties and its synthesized derivatives in MC-100 gel was carried out using the model of experimental full thickness skin wounds. It was determined that N-sulfosuccinoyl chitosan derivatives added into the gel in a concentration of 0.05% possess the higher wound healing activity in comparison with other chitosan derivatives and decrease the half-healing period of wounds 2–3 times in comparison with the control.

T. P. Alekseeva

Papers

Wound-healing properties of copper nanoparticles as a function of physicochemical parameters

Wound healing potential of chitosan and N-sulfosuccinoyl chitosan derivatives