The neglected role of copper ions in wound healing

Copper nanoparticles promote rapid wound healing in acute full thickness defect via acceleration of skin cell migration, proliferation, and neovascularization

Worldwide, impaired wound healing leads to a large burden of morbidity and mortality. Current treatments have several limitations. Recently, nanomaterials such as copper nanoparticles (CuNPs) have attracted considerable research interest. Here, we investigated the potential therapeutic effect of various CuNPs concentrations (1 μM, 10 μM, 100 μM, 1 mM, and 10 mM) and sizes (20 nm, 40 nm, 80 nm) in wound healing. Our results revealed that the 10 μM concentration of 40 nm CuNPs and the 1 μM concentration of 80 nm CuNPs were not toxic to the cultured fibroblast, endothelial, and keratinocyte cells, and also 1 μM concentration of 80 nm CuNPs enhanced endothelial cell migration and proliferation. Extensive assessment of in vivo wound healing demonstrated that the 1 μM concentration of 80 nm CuNPs accelerated wound healing over a shorter time via formation of granulation tissue and higher new blood vessels. Importantly, serum biochemical analysis confirmed that the 40 nm CuNP (10 μM) and 80 nm CuNP (1 μM) did not show any accumulation in the liver during wound healing. Overall, our results have indicated that the 1 μM concentration of 80 nm CuNPs is a promising NP for wound healing applications without adverse side effects.

EPR Spectroscopic Examination of Different Types of Paramagnetic Centers in the Blood in the Course of Burn Healing

The multicomponent electron paramagnetic resonance spectra of the blood during healing of skin burned wounds treated with a new generation biodegradable dressings containing poly(lactide-co-glycolide) were analysed. The evolution of different types of paramagnetic centers in the blood with time of healing was determined. The EPR spectra of the blood samples at 230 K temperature were measured at 1, 10, and 21 days after burning of the pig skin. The EPR lines of the following paramagnetic centers: the high-spin Fe³⁺ in methemoglobin (line I), high-spin Fe³⁺ in transferrin (line II), and Cu²⁺ in ceruloplasmin and free radicals (line III) were observed in the X-band (9.3 GHz) spectra of the blood. The multicomponent structure of the EPR spectra of the tested blood samples depended on the time of the healing of the burned wounds. The amount of the high-spin Fe³⁺ in methemoglobin (line I) in the blood decreased after 21 days of the healing of the burned wounds. The amount of the high-spin Fe³⁺ in transferrin (line II) slightly increased after 21 days of therapy with the basis. The amount of Cu²⁺ in ceruloplasmin and free radicals (line III) in the blood was very high after 10 days of therapy. At the first day of the healing of the burned wounds, the highest amount of the high-spin Fe³⁺ in methemoglobin (line I), the relatively lower amounts of the high-spin Fe³⁺ in transferrin (line II), and Cu²⁺ in ceruloplasmin and free radicals (line III) existed in the blood. In the medium phase (after 10 days) of the healing of the burned wounds, the extremely higher amounts of Cu²⁺ in ceruloplasmin and free radicals (line III) appeared in the blood. In the last phase (after 21 days), only the low differences between the amounts of the high-spin Fe³⁺ in methemoglobin (line I), the high-spin Fe³⁺ in transferrin (line II), and Cu²⁺ in ceruloplasmin and free radicals (line III) were observed. The present study may serve as a starting point for the development of a new technique for monitoring molecular complexes containing iron Fe³⁺ (methemoglobin, transferrin) or copper Cu²⁺ ions (ceruloplasmin) and free radicals in the blood during wound healing.

Nanocarrier-based systems for wound healing

In general, the systems intended for the treatment and recovery of wounds, seek to act as a coating for the damaged area, maintaining an adequate level of humidity, reducing pain, and preventing the invasion and proliferation of microorganisms. Although many of the systems that are currently on the market meet the purposes mentioned above, with the arrival of nanotechnology, it has sought to improve the performance of these coatings. The variety of nano-systems that have been proposed is very extensive, including the use of very different materials (natural or synthetic) ranging from polymers or lipids to systems derived from microorganisms. With the objective of improving the performance of the systems, seeking to combat several of the problems that arise in a wound, especially when it is chronic, these materials have been combined, giving rise to nanocomposites or scaffolds. In recent years, the interest in the development of systems for the treatment of wounds is notable, which is reflected in the increase in publications related to the subject. Therefore, this document presents generalities of systems involving nanocarriers, mentioning some examples of representative systems of each case.

Copper metal-organic frameworks loaded on chitosan film for the efficient inhibition of bacteria and local infection therapy

Although multiple advanced antibacterial and sterilization materials are available, bacterial infections still remain a big challenge in wound healing as they usually induce serious complications and cannot be thoroughly eliminated. Herein, we report an antibacterial film composed of the naturally derived polysaccharide chitosan (CS) and a copper metal-organic framework (HKUST-1) as a multifunctional platform for antibacterial and local infection therapy applications. As expected, the as-prepared HKUST-1/CS film possessed versatile abilities such as slow release of copper ions and reduced cytotoxicity; moreover, fluorescent staining and morphological changes of the bacteria treated with the HKUST-1/CS film confirmed the antibacterial activity of the fabricated film. Furthermore, in vivo results revealed that the HKUST-1/CS film could simultaneously kill bacteria and promote vessel regeneration; this resulted in an enhanced wound closure rate during the local infection therapy process. Overall, these results highlight that the HKUST-1/CS film exhibits significant potential as a suitable and promising wound dressing.

Copper (II) Ions Activate Ligand-Independent Receptor Tyrosine Kinase (RTK) Signaling Pathway

Receptor tyrosine kinase (RTK) is activated by its natural ligand, mediating multiple essential biological processes. Copper (II) ions are bioactive ions and are crucial in the regulation of cell signaling pathway. However, the crosstalk between copper (II) ions and RTK-mediated cellular signaling remains unclear. Herein, we reported the effect of copper (II) ions on the ligand-independent RTK cellular signaling pathway. Our results indicate that both EGFR and MET signaling were activated by copper (II) in the absence of the corresponding ligands, EGF and HGF, respectively. Consequently, copper (II) ions initiate two RTK-mediated downstream signal transductions, including AKT and ERK. Moreover, copper (II) significantly increased proliferation and cellular migration. Our study proposes a novel role of copper in RTK-mediated signaling for growth factor-independent cancer cell proliferation and migration, implying that targeting both the copper (II) and growth factor in tumor microenvironments may be necessary for cancer treatment.

Using Bioactive Glasses in the Management of Burns

The management of burn injuries is considered an unmet clinical need and, to date, no fully satisfactory solution exists to this problem. This mini-review aims to explore the potential of bioactive glasses (BGs) for burn care due to the therapeutic effects of their ionic dissolution products. BGs have been studied for more than 40 years and boast a long successful history in the substitution of damaged tissues, especially bone. Considering their exceptional versatility and attractive characteristics, these synthetic materials have also recently been proposed in the treatment of soft tissue-related disorders such as skin wounds. Specifically, improving fibroblast proliferation, inducing angiogenesis, and eliciting antibacterial activity (with the additional advantage of avoiding administration of antibiotics) are all considered as key added values carried by BGs in the treatment of burn injuries. However, some issues deserve careful consideration while proceeding with the research, including the selection of suitable BG compositions, appropriate forms of application (e.g., BG fibers, ointments or composite patches), as well as the procedures for reliable in vivo testing.

Laser-Activatable CuS Nanodots to Treat Multidrug-Resistant Bacteria and Release Copper Ion to Accelerate Healing of Infected Chronic Nonhealing Wounds

Chronic nonhealing wounds have imposed serious challenges in the clinical practice, especially for the patients infected with multidrug-resistant microbes. Herein, we developed an ultrasmall copper sulfide (covellite) nanodots (CuS NDs) based dual functional nanosystem to cure multidrug-resistant bacteria-infected chronic nonhealing wound. The nanosystem could eradicate multidrug-resistant bacteria and expedite wound healing simultaneously owing to the photothermal effect and remote control of copper-ion release. The antibacterial results indicated that the combination treatment of photothermal CuS NDs with photothermal effect initiated a strong antibacterial effect for drug-resistant pathogens including methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase Escherichia coli both in vitro and in vivo. Meanwhile, the released Cu2+ could promote fibroblast cell migration and endothelial cell angiogenesis, thus accelerating wound-healing effects. In MRSA-infected diabetic mice model, the nanosystem exhibited synergistic wound healing effect of infectious wounds in vivo and demonstrated negligible toxicity and nonspecific damage to major organs. The combination of ultrasmall CuS NDs with photothermal therapy displayed enhanced therapeutic efficacy for chronic nonhealing wound in multidrug-resistant bacterial infections, which may represent a promising class of antibacterial strategy for clinical translation.

A controllable local drug delivery system based on porous fibers for synergistic treatment of melanoma and promoting wound healing

A controllable local drug delivery system can effectively inhibit melanoma growth with chemo-photothermal synergistic therapy and accelerate wound healing.

Role of poly(ethylene oxide) in copper-containing composite used for intrauterine contraceptive devices

Copper-containing composite is a cupric ions release system to prepare a novel copper intrauterine devices (Cu-IUDs), its biocompatibility and weight of the prepared composite Cu-IUDs are directly relevant to its such side-effects as pain and bleeding. To improve its biocompatibility and reduce its weight of such a composite Cu-IUDs, a copper-containing composite based on polymer alloy of poly(ethylene oxide) (PEO) and low-density polyethylene (LDPE) is developed. Here the role of its PEO in this novel cupric ions release system is reported. The results show that its cupric ions release rate can be adjusted easily by only changing its PEO content, and it increases remarkably with the increase of its PEO content. Our study also show that this influence is caused by the improvement of its hydrophilicity and the formation of its porous structure owing to the introduction of PEO. The improvement of its hydrophilicity make it easier for the surrounding aqueous solution to infiltrate into the composite, and the formation of its porous structure provide more routes for entry of the aqueous solution and diffusion of the released cupric ions. All these results indicate that the Cu/PEO/LDPE composite is a potential material that can be used to prepare such cupric ions release micro-devices as Cu-IUDs with slighter side-effects through its smaller weight.

Electroactive biomaterials: Vehicles for controlled delivery of therapeutic agents for drug delivery and tissue regeneration

Electrical stimulation for delivery of biochemical agents such as genes, proteins and RNA molecules amongst others, holds great potential for controlled therapeutic delivery and in promoting tissue regeneration. Electroactive biomaterials have the capability of delivering these agents in a localized, controlled, responsive and efficient manner. These systems have also been combined for the delivery of both physical and biochemical cues and can be programmed to achieve enhanced effects on healing by establishing control over the microenvironment. This review focuses on current state-of-the-art research in electroactive-based materials towards the delivery of drugs and other therapeutic signalling agents for wound care treatment. Future directions and current challenges for developing effective electroactive approach based therapies for wound care are discussed.

Copper Metal-Organic Framework Nanoparticles Stabilized with Folic Acid Improve Wound Healing in Diabetes

The successful treatment of chronic nonhealing wounds requires strategies that promote angiogenesis, collagen deposition, and re-epithelialization of the wound. Copper ions have been reported to stimulate angiogenesis; however, several applications of copper salts or oxides to the wound bed are required, leading to variable outcomes and raising toxicity concerns. We hypothesized that copper-based metal-organic framework nanoparticles (Cu-MOF NPs), referred to as HKUST-1, which are rapidly degraded in protein solutions, can be modified to slowly release Cu²⁺, resulting in reduced toxicity and improved wound healing rates. Folic acid was added during HKUST-1 synthesis to generate folic-acid-modified HKUST-1 (F-HKUST-1). The effect of folic acid incorporation on NP stability, size, hydrophobicity, surface area, and copper ion release profile was measured. In addition, cytotoxicity and in vitro cell migration processes due to F-HKUST-1 and HKUST-1 were evaluated. Wound closure rates were assessed using the splinted excisional dermal wound model in diabetic mice. The incorporation of folic acid into HKUST-1 enabled the slow release of copper ions, which reduced cytotoxicity and enhanced cell migration in vitro. In vivo, F-HKUST-1 induced angiogenesis, promoted collagen deposition and re-epithelialization, and increased wound closure rates. These results demonstrate that folic acid incorporation into HKUST-1 NPs is a simple, safe, and promising approach to control Cu²⁺ release, thus enabling the direct application of Cu-MOF NPs to wounds.

Development of banana (Musa balbisiana) pseudo stem fiber as a surgical bio-tool to avert post-operative wound infections

The search to develop an ideal suture material encourages us to explore novel suture biomaterials with superior characteristics to the current commercially available products. Surgical sutures play a crucial role in the development of post-operative wound infection by acting as a substrate for biofilm formation which leads to dehisced wounds. In this context, the present invention meets this need by fabricating banana (Musa balbisiana) fibre into an advanced antimicrobials releasing suture biomaterial (BSc) for the prevention of post-operative wound infection. Suture material developed from banana pseudo stem fiber was impregnated with chloramphenicol, clotrimazole and growth factors with the aid of a hydro-gel system. The fabricated suture material was found to be biocompatible towards human erythrocytes and L929 mouse fibroblast cells. BSc exhibited promising physico-chemical characteristics which were comparable to the commercially available Bombyx mori silk fibroin (BMSF) suture. BSc displayed a biphasic release pattern with sustained release of chloramphenicol for up to 140 h. Apart from being environment friendly and having a facile fabrication method, this advanced suture biomaterial showed broad spectrum in vitro antimicrobial activity against bacterial and fungal pathogens. BSc successfully impeded biofilm formation on its surface, as is evident from the confocal microscopy analysis. This contributes to superior wound healing efficacy in terms of reduced microbial burden and a subsequent decrease in the inflammatory cytokine levels. Histopathological observations further supported the pronounced healing efficacy of BSc sutured wounds. The findings of this study establish the banana pseudo stem fiber as a novel advanced suture biomaterial to prevent post-operative wound infections.

A novel antimicrobial suture biomaterial developed from banana waste fibers to avert post operative wound infections.

Antimicrobials tethering on suture surface through a hydrogel: a novel strategy to combat postoperative wound infections

The present study aimed to develop a novel biocompatible suture biomaterial from Eri silk waste to avoid surgical site infections.