The downside of antimicrobial agents for wound healing

Comprehensive developmental investigation on simvastatin enriched bioactive film forming spray using the quality by design paradigm: a prospective strategy for improved wound healing

The use of topical antimicrobials in wound healing presents challenges like risk of drug resistance and toxicity to local tissue. Simvastatin (SIM), a lipid-lowering agent which reduces the risk of cardiovascular events, is repurposed for its pleiotropic effect in wound healing. A bioactive bioadhesive polymer-based film forming spray (FFS) formulation of SIM was designed using chitosan, collagen, hyaluronic acid and optimised by employing the DoE approach. Optimised formulation demonstrated moderate viscosity (12.5 ± 0.3 cP), rapid film formation (231 ± 5.6 s), flexibility, tensile strength and sustained drug release (T80 - time for 80% drug release - 9.05 ± 0.7 h). Scanning electron microscopy (SEM) verified uniformly dispersed drug within the composite polymer matrix. SIM FFS demonstrated antimicrobial activity against gram positive and gram negative bacteria. In vivo excision wound model studies in mice affirmed the beneficent role of bioactive polymers and the efficacy of SIM FFS in wound contraction and closure, tissue remodelling and re-epithelization in comparison to standard antimicrobial preparation. Cytokines TNF- alpha, IL-6 were downregulated and IL-10 was upregulated. Biochemical markers; hydroxyproline, hexosamine and histopathology were consistent with wound contraction observed. This is an exploratory effort in repurposing SIM for wound healing in a novel dosage form, underscoring its potential as an alternative to conventional topical antimicrobials.

Two-dimensional nanomaterials: A multifunctional approach for robust for diabetic wound repair

Diabetic wounds pose a clinical challenge due to persistent inflammation, severe bacterial infections, inadequate vascularization, and pronounced oxidative stress. Current therapeutic modalities fail to provide satisfactory outcomes in managing these conditions, resulting in considerable patient distress. Two-dimensional nanomaterials (2DNMs), characterized by their unique nanosheet structures, expansive surface areas, and remarkable physicochemical properties, have garnered considerable attention for their potential in therapeutic applications. Emerging 2DNMs can be loaded with various pharmacological agents, including small molecules, metal ions, and liposomes. Moreover, they can be integrated with various biomaterials such as hydrogels, microneedles, and microspheres, thus demonstrating unprecedented advantages in expediting the healing process of diabetic wounds. Moreover, 2DNMs exhibit exceptional performance characteristics, including high biocompatibility, effective antimicrobial properties, optimal phototherapeutic effects, and enhanced electrostimulation capabilities. These properties enable them to modulate the wound microenvironment, leading to widespread application in tissue repair with remarkable outcomes. This review delineates several emerging 2DNMs, such as graphene and its derivatives, black phosphorus, MXenes, and transition metal dichalcogenides, in the context of diabetic wound repair. Furthermore, it elucidates the translational challenges and future perspectives of 2DNMs in wound healing treatments. Overall, 2DNMs present a highly promising strategy for ameliorating diabetic wounds, thus providing novel avenues for diagnostic and therapeutic strategies in diabetic wound management.

Evaluation of the efficacy of topical rifamycin application on postoperative complications after lower impacted wisdom teeth surgery

PURPOSE

This study aimed to evaluate the efficacy of a single-dose topical rifamycin application on postoperative complications after impacted lower third molar surgery.

MATERIALS AND METHODS

This prospective, controlled clinical study consisted of individuals with bilaterally impacted lower third molars that would be extracted for orthodontic reasons. The extraction sockets were irrigated with 3 ml/250 mg of rifamycin solution in Group 1, while in Group 2 (control group) the extraction sockets were irrigated with 20 ml of physiological saline. Pain intensity was measured daily for 7 days by using visual analog scale. Trismus and edema were evaluated preoperatively and on the postoperative days 2 and 7 by calculating the proportional changes in maximum mouth opening and mean distance between reference points of the face, respectively. Paired samples t-test, Wilcoxon signed rank test and Chi-square test were used to analyze the study variables.

RESULTS

35 patients (19 female, 16 male) were included in the study. The mean age of all participants was 22.19±4.98. Alveolitis was observed in 8 patients, (6 in the control group, 2 in the rifamycin group). There was no statistically significant difference between groups in terms of trismus and swelling measurements on the 2nd and 7th postoperative days (p>0.05). VAS scores were significantly low in rifamycin group on postoperative days 1 and 4 (p<0.05).

CONCLUSION

Within the limits of the present study, topical rifamycin application reduced the incidence of alveolitis, prevented infection, and provided analgesic effect after surgical removal of impacted third molars.

Cannabinoids in Integumentary Wound Care: A Systematic Review of Emerging Preclinical and Clinical Evidence

This systematic review critically evaluates preclinical and clinical data on the antibacterial and wound healing properties of cannabinoids in integument wounds. Comprehensive searches were conducted across multiple databases, including CINAHL, Cochrane library, Medline, Embase, PubMed, Web of Science, and LILACS, encompassing records up to May 22, 2024. Eighteen studies met the inclusion criteria. Eleven were animal studies, predominantly utilizing murine models (n = 10) and one equine model, involving 437 animals. The seven human studies ranged from case reports to randomized controlled trials, encompassing 92 participants aged six months to ninety years, with sample sizes varying from 1 to 69 patients. The studies examined the effects of various cannabinoid formulations, including combinations with other plant extracts, crude extracts, and purified and synthetic cannabis-based medications administered topically, intraperitoneally, orally, or sublingually. Four animal and three human studies reported complete wound closure. Hemp fruit oil extract, cannabidiol (CBD), and GP1a resulted in complete wound closure in twenty-three (range: 5-84) days with a healing rate of 66-86% within ten days in animal studies. One human study documented a wound healing rate of 3.3 cm2 over 30 days, while three studies on chronic, non-healing wounds reported an average healing time of 54 (21-150) days for 17 patients by oral oils with tetrahydrocannabinol (THC) and CBD and topical gels with THC, CBD, and terpenes. CBD and tetrahydrocannabidiol demonstrated significant potential in reducing bacterial loads in murine models. However, further high-quality research is imperative to fully elucidate the therapeutic potential of cannabinoids in the treatment of bacterial skin infections and wounds. Additionally, it is crucial to delineate the impact of medicinal cannabis on the various phases of wound healing. This study was registered in PROSPERO (CRD42021255413).

Topical and transdermal botanical formulations of the Chinese pharmacopoeia-A review

In pharmaceutics, ingredients are classified as active ingredients and excipients. In topical/transdermal phytomedicines, an ingredient may serve both functions. Published information on these dual-purpose ingredients and their pharmacological relevance is limited. An intriguing scenario arises in traditional Chinese medicine (TCM) formulations, where active ingredients and excipients are undifferentiated. This study analyzes ingredients in TCM topical/transdermal formulations, aiming at harmonization of understanding of TCMs. The most commonly recorded ingredients from such formulations in the Chinese pharmacopoeia 2020 (ChP 2020) are reviewed, aiming at developing innovative topical/transdermal phytomedicines. Current editions of Chinese historical documents were reviewed to explore the principles underlying the use of these ingredients. TCM formulations containing botanical drugs for topical/transdermal application were selected from the ChP 2020. The use of botanical materials in TCM formulations is guided by the "Jun-Chen-Zuo-Shi" principle rooted in Yin-Yang and the five elements' theories. In the ChP 2020, 155 botanical drugs, along with 40 excipients (from the "procedure" section, focusing on processing and technical parameters), were identified from 34 botanical formulations intended for topical/transdermal application. Pungent and aromatic botanical materials were the most frequently recorded. Adhesive plasters were the most commonly recorded TCM dosage form, employing specific matrix blends. This new perspective of study reveals the prevalence of pungent and aromatic botanical materials, the common use of adhesive plasters, multifunctional properties of botanical oils, and formulation adaptability in TCM topical/transdermal products. These insights should inform novel formulation designs for both pharmaceutical and phytopharmacological research.

Unveiling the Unexplored Multifactorial Potential of 5-Aminosalicylic Acid in Diabetic Wound Therapy

Diabetic wounds (DWs) are considered chronic complications observed in patients suffering from type 2 diabetes mellitus (DM). Usually, DWs originate from the interplay of inflammation, oxidation, impaired tissue re-epithelialization, vasculopathy, nephropathy, and neuropathy, all of which are related to insulin resistance and sensitivity. The conventional approaches available for the treatment of DWs are mainly confined to the relief of wound pressure, debridement of the wound, and management of infection. In this paper, we speculate that treatment of DWs with 5-aminosalicylic acid (5-ASA) and subsequent activation of peroxisome proliferator-activated receptor gamma (PPAR-γ) and transforming growth factor beta (TGF-β) via the AhR pathway might be highly beneficial for DW patients. This estimation is based on several lines of evidence showing that 5-ASA and PPAR-γ activation are involved in the restoration of insulin sensitivity, re-epithelialization, and microcirculation. Additionally, 5-ASA and TGF-β activate inflammation and the production of pro-inflammatory mediators. Suitable stabilized formulations of 5-ASA with high absorption rates are indispensable for scrutinizing its probable pharmacological benefits since 5-ASA is known to possess lower solubility profiles because of its reduced permeability through skin tissue. In vitro and in vivo studies with stabilized formulations and a control (placebo) are mandatory to determine whether 5-ASA indeed holds promise for the curative treatment of DWs.

Exploring the wound healing activity of phytosomal gel of Annona squamosa and Cinnamomum tamala leaves ethanolic extracts with antioxidant and antimicrobial activities in S aureus infected excision wound model

Wound healing is a natural process but it is impaired in certain conditions like age, stress, health, immunity status and microbial infection. Particularly in cases of chronic wounds, infection is nearly often the main and unavoidable obstacle to wound healing. For this purpose, leaves of Annona squamosa and Cinnamomum tamala were selected based on their ethnopharmacological uses and reported pharmacological activities. The ethanolic extracts of both plant parts i.e. ethanolic extracts of Annona squamosa (ASEE) and Cinnamomum tamala (CTEE) were evaluated for their antioxidant and antimicrobial activities individually as well as in 1:1 combination as Polyherbal Ethanolic extract (PHEE). In our previous work both these ethanolic extracts were combined and phytosomes were prepared by thin layer hydration method and optimized for vesicle size and entrapment efficiency. The phytosomes were then incorporated into Carbopol gel matrix. In this present study the selected phytosomal gel was tested in two different concentrations (2% and 5%) for in vivo wound healing activity using S. aureus infected excision wound model. The various parameters examined were percentage wound contraction, epithelization period, bacteriological quantification, biochemical parameters like Superoxide dismutase (SOD), Catalase and hydroxyproline. The PHEE exhibited synergistic antioxidant activity. The PHEE also showed enhanced antimicrobial activity against bacteria namely gram-positive S. aureus, gram-negative E. Coli. The phytosomal gel showed increased wound contraction, reduced time of epithelization, increased hydroxyproline content, increased levels of SOD and Catalase enzymes and reduced bacterial load when compared with Povidone iodine ointment as standard in S. aureus infected excision wound model.

The interactive effects of medicinal dyes with conventional antimicrobials against skin pathogens

AIMS

This study aimed to explore potential synergistic effects of medicinal dyes with antimicrobials against pathogens responsible for skin infections.

METHODS AND RESULTS

Antimicrobial testing was conducted using minimum inhibitory concentrations and minimum bactericidal/fungicidal concentration assays. The fractional inhibitory index (ΣFIC) of combinations was calculated, and isobolograms were constructed on selected combinations. Toxicity studies were conducted using the brine-shrimp lethality assay. Combination (1:1 ratio) studies noted that 26% of dye-antibiotic combinations were synergistic against the Gram-positive strains, 15% against the Gram-negative strains, and 14% against the yeasts. The Mercurochrome: Betadine® combination noted synergy at ratios against all the Staphylococcus aureus strains with ΣFIC values ranging from 0.05 to 0.48. The combination of Gentian violet with Gentamycin noted a 15-fold decrease in toxicity, and a selectivity index of 977.50 against the Escherichia coli (DSM 22314) strain. Time-kill studies were conducted on the combinations with the highest safe selectivity index (SI) value and lowest safe SI value i.e. Gentian violet with Gentamycin and Malachite green with Neomycin. Both combinations demonstrated better antimicrobial activity in comparison to the independent values and the controls.

CONCLUSION

This study highlights the potential for medicinal dye combinations as a treatment for skin infections.

Chitosan-based multifunctional oxygenating antibiotic hydrogel dressings for managing chronic infection in diabetic wounds

Current treatment strategies for infection of chronic wounds often result in compromised healing and necrosis due to antibiotic toxicity, and underlying biomarkers affected by treatments are not fully known. Here, a multifunctional dressing was developed leveraging the unique wound-healing properties of chitosan, a natural polysaccharide known for its numerous benefits in wound care. The dressing consists of an oxygenating perfluorocarbon functionalized methacrylic chitosan (MACF) hydrogel incorporated with antibacterial polyhexamethylene biguanide (PHMB). A non-healing diabetic infected wound model with emerging metabolomics tools was used to explore the anti-infective and wound healing properties of the resultant multifunctional dressing. Direct bacterial bioburden assessment demonstrated superior antibacterial properties of hydrogels over a commercial dressing. However, wound tissue quality analyses confirmed that sustained PHMB for 21 days resulted in tissue necrosis and disturbed healing. Therefore, a follow-up comparative study investigated the best treatment course for antiseptic application ranging from 7 to 21 days, followed by the oxygenating chitosan-based MACF treatment for the remainder of the 21 days. Bacterial counts, tissue assessments, and lipidomics studies showed that 14 days of application of MACF-PHMB dressings followed by 7 days of MACF dressings provides a promising treatment for managing infected non-healing diabetic skin ulcers.

Synergistic Cellular Responses Conferred by Concurrent Optical and Magnetic Stimulation Are Attenuated by Simultaneous Exposure to Streptomycin: An Antibiotic Dilemma

Concurrent optical and magnetic stimulation (COMS) combines extremely low-frequency electromagnetic and light exposure for enhanced wound healing. We investigated the potential mechanistic synergism between the magnetic and light components of COMS by comparing their individual and combined cellular responses. Lone magnetic field exposure produced greater enhancements in cell proliferation than light alone, yet the combined effects of magnetic fields and light were supra-additive of the individual responses. Reactive oxygen species were incrementally reduced by exposure to light, magnetics fields, and their combination, wherein statistical significance was only achieved by the combined COMS modality. By contrast, ATP production was most greatly enhanced by magnetic exposure in combination with light, indicating that mitochondrial respiratory efficiency was improved by the combination of magnetic fields plus light. Protein expression pertaining to cell proliferation was preferentially enhanced by the COMS modality, as were the protein levels of the TRPC1 cation channel that had been previously implicated as part of a calcium-mitochondrial signaling axis invoked by electromagnetic exposure and necessary for proliferation. These results indicate that light facilitates functional synergism with magnetic fields that ultimately impinge on mitochondria-dependent developmental responses. Aminoglycoside antibiotics (AGAs) have been previously shown to inhibit TRPC1-mediated magnetotransduction, whereas their influence over photomodulation has not been explored. Streptomycin applied during exposure to light, magnetic fields, or COMS reduced their respective proliferation enhancements, whereas streptomycin added after the exposure did not. Magnetic field exposure and the COMS modality were capable of partially overcoming the antagonism of proliferation produced by streptomycin treatment, whereas light alone was not. The antagonism of photon-electromagnetic effects by streptomycin implicates TRPC1-mediated calcium entry in both magnetotransduction and photomodulation. Avoiding the prophylactic use of AGAs during COMS therapy will be crucial for maintaining clinical efficacy and is a common concern in most other electromagnetic regenerative paradigms.

Immunomodulatory poly(L-lactic acid) nanofibrous membranes promote diabetic wound healing by inhibiting inflammation, oxidation and bacterial infection

Background

Given the significant impact on human health, it is imperative to develop novel treatment approaches for diabetic wounds, which are prevalent and serious complications of diabetes. The diabetic wound microenvironment has a high level of reactive oxygen species (ROS) and an imbalance between proinflammatory and anti-inflammatory cells/factors, which hamper the healing of chronic wounds. This study aimed to develop poly(L-lactic acid) (PLLA) nanofibrous membranes incorporating curcumin and silver nanoparticles (AgNPs), defined as PLLA/C/Ag, for diabetic wound healing.

Methods

PLLA/C/Ag were fabricated via an air-jet spinning approach. The membranes underwent preparation and characterization through various techniques including Fourier-transform infrared spectroscopy, measurement of water contact angle, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, assessment of in vitro release of curcumin and Ag+, testing of mechanical strength, flexibility, water absorption and biodegradability. In addition, the antioxidant, antibacterial and anti-inflammatory properties of the membranes were evaluated in vitro, and the ability of the membranes to heal wounds was tested in vivo using diabetic mice.

Results

Loose hydrophilic nanofibrous membranes with uniform fibre sizes were prepared through air-jet spinning. The membranes enabled the efficient and sustained release of curcumin. More importantly, antibacterial AgNPs were successfully reduced in situ from AgNO3. The incorporation of AgNPs endowed the membrane with superior antibacterial activity, and the bioactivities of curcumin and the AgNPs gave the membrane efficient ROS scavenging and immunomodulatory effects, which protected cells from oxidative damage and reduced inflammation. Further results from animal studies indicated that the PLLA/C/Ag membranes had the most efficient wound healing properties, which were achieved by stimulating angiogenesis and collagen deposition and inhibiting inflammation.

Conclusions

In this research, we successfully fabricated PLLA/C/Ag membranes that possess properties of antioxidants, antibacterial agents and anti-inflammatory agents, which can aid in the process of wound healing. Modulating wound inflammation, these new PLLA/C/Ag membranes serve as a novel dressing to enhance the healing of diabetic wounds.

Polyhexamethylene Biguanide Reduces High-Risk Human Papilloma Virus Viral Load in Cervical Cell Samples Derived from ThinPrep Pap Test

Human papilloma virus (HPV) infection and its progression still represent a great medical challenge worldwide. Clinical evidence has demonstrated the beneficial effects of polyhexamethylene biguanide (PHMB) on HPV clinical manifestations; however, evidence of the effect of this molecule on HPV viral load is still lacking. In this in vitro study, 13 ThinPrep Papanicolaou (Pap) tests were treated with a PHMB solution (0.10 g/100 mL) for 2 h. We observed no cytological changes but a significant reduction in the viral load of high-risk (HR) HPV after PHMB treatment, also revealing a dose-dependent antiviral effect. In addition, by stratifying the obtained results according to HR-HPV genotype, we observed a significant reduction in the viral load of HPV 16, P2 (56, 59, 66), 31, and P3 (35, 39, 68) and a strong decrease in the viral load of HPV 45, 52, and P1 (33, 58). Overall, 85% of the analyzed cervical cell samples exhibited an improvement in HPV viral load after PHMB exposure, while only 15% remain unchanged. For the first time, the data from this pilot study support the activity of PHMB on a specific phase of the HPV viral lifecycle, the one regarding the newly generated virions, reducing viral load and thus blocking the infection of other cervical cells.

Synthesis, molecular modelling, and antibacterial evaluation of new sulfonamide-dyes based pyrrole compounds

In this study, we synthesized new series of 5-oxo-2-phenyl-4-(arylsulfamoyl)sulphenyl) hydrazono)-4,5-dihydro-1H-pyrrole-3-carboxylate hybrids 4a-f with the goal of overcoming sulfonamide resistance and identifying novel therapeutic candidates by chemical changes. The chemical structures of the synthesized hybrids were established over the spectroscopic tools. The frontier molecular orbitals configuration and energetic possessions of the synthesized compounds were discovered utilizing DFT/B3LYP/6-311++ G** procedure. The 3D plots of both HOMO and LUMO showed comparable configuration of both HOMO and LUMO led to close values of their energies. Amongst the prepared analogues, the sulfonamide hybrids 4a-f, hybrid 4a presented potent inhibitory towards S. typhimurium with (IZD = 15 mm, MIC = 19.24 µg/mL) and significant inhibition with (IZD = 19 mm, MIC = 11.31 µg/mL) against E.coli in contrast to sulfonamide (Sulfamethoxazole) reference Whereas, hybrid 4d demonstrated potent inhibition with (IZD = 16 mm, MIC = 19.24 µg/mL) against S. typhimurium with enhanced inhibition against E. Coli, Additionally, the generated sulfonamide analogues'' molecular docking was estimated over (PDB: 3TZF and 6CLV) proteins. Analogue 4e had the highest documented binding score as soon as linked to the other analogues. The docking consequences were fitting and addressed with the antibacterial valuation.

From nature to nanomedicine: bioengineered metallic nanoparticles bridge the gap for medical applications

The escalating global challenge of antimicrobial resistance demands innovative approaches. This review delves into the current status and future prospects of bioengineered metallic nanoparticles derived from natural sources as potent antimicrobial agents. The unique attributes of metallic nanoparticles and the abundance of natural resources have sparked a burgeoning field of research in combating microbial infections. A systematic review of the literature was conducted, encompassing a wide range of studies investigating the synthesis, characterization, and antimicrobial mechanisms of bioengineered metallic nanoparticles. Databases such as PubMed, Scopus, Web of Science, ScienceDirect, Springer, Taylor & Francis online and OpenAthen were extensively searched to compile a comprehensive overview of the topic. The synthesis methods, including green and sustainable approaches, were examined, as were the diverse biological sources used in nanoparticle fabrication. The amalgamation of metallic nanoparticles and natural products has yielded promising antimicrobial agents. Their multifaceted mechanisms, including membrane disruption, oxidative stress induction, and enzyme inhibition, render them effective against various pathogens, including drug-resistant strains. Moreover, the potential for targeted drug delivery systems using these nanoparticles has opened new avenues for personalized medicine. Bioengineered metallic nanoparticles derived from natural sources represent a dynamic frontier in the battle against microbial infections. The current status of research underscores their remarkable antimicrobial efficacy and multifaceted mechanisms of action. Future prospects are bright, with opportunities for scalability and cost-effectiveness through sustainable synthesis methods. However, addressing toxicity, regulatory hurdles, and environmental considerations remains crucial. In conclusion, this review highlights the evolving landscape of bioengineered metallic nanoparticles, offering valuable insights into their current status and their potential to revolutionize antimicrobial therapy in the future.

Recent advances on 3D-bioprinted gelatin methacrylate hydrogels for tissue engineering in wound healing: A review of current applications and future prospects

Advancements in 3D bioprinting, particularly the use of gelatin methacrylate (GelMA) hydrogels, are ushering in a transformative era in regenerative medicine and tissue engineering. This review highlights the pivotal role of GelMA hydrogels in wound healing and skin regeneration. Its biocompatibility, tunable mechanical properties and support for cellular proliferation make it a promising candidate for bioactive dressings and scaffolds. Challenges remain in optimizing GelMA hydrogels for clinical use, including scalability of 3D bioprinting techniques, durability under physiological conditions and the development of advanced bioinks. The review covers GelMA's applications from enhancing wound dressings, promoting angiogenesis and facilitating tissue regeneration to addressing microbial infections and diabetic wound healing. Preclinical studies underscore GelMA's potential in tissue healing and the need for further research for real-world applications. The future of GelMA hydrogels lies in overcoming these challenges through multidisciplinary collaboration, advancing manufacturing techniques and embracing personalized medicine paradigms.

Alginate and Chitosan-Based Hydrogel Enhance Antibacterial Agent Activity on Topical Application

Untreated topical infections can become chronic, posing serious health issues. Optimal skin adherence is crucial in addressing such infections. In this context, chitosan and alginate emerge as promising candidates for use as a foundation in the development of topical hydrogels. The aim of this review is to examine the literature on topical hydrogel formulations that use chitosan and alginate as foundations, specifically in the context of topical antibacterial agents. The research methodology involves a literature review by examining articles published in databases such as PubMed, Scopus, ScienceDirect, and Google Scholar. The keywords employed during the research were "Alginate", "Chitosan", "Hydrogel", and "Antibacterial". Chitosan and alginate serve as bases in topical hydrogels to deliver various active ingredients, particularly antibacterial agents, as indicated by the search results. Both have demonstrated significant antibacterial effectiveness, as evidenced by a reduction in bacterial colony counts and an increase in inhibition zones. This strongly supports the idea that chitosan and alginate could be used together to make topical hydrogels that kill bacteria that work well. In conclusion, chitosan and alginate-based hydrogels show great potential in treating bacterial infections on the skin surface. The incorporation of chitosan and alginate into hydrogel formulations aids in retaining antibacterial agents, allowing for their gradual release over an optimal period. Therefore, hydrogels specifically formulated with chitosan and alginate have the potential to serve as a solution to address challenges in the treatment of topical bacterial infections.

Highly biocidal poly(vinyl alcohol)-hydantoin/starch hybrid gels: A "Trojan Horse" for Bacillus subtilis

HYPOTHESIS

Poly (vinyl alcohol) (PVA) cryogels can be functionalized with n-Halamines to confer biocidal features useful for their application as wound-dressing tools. Their efficacy can be boosted by stably embedding a polymeric bacterial food source (e.g., starch) in the gel matrix. The bioavailability of the food source lures bacteria inside the gel network via chemotactic mechanisms, promoting their contact with the biocidal functionalities and their consequent inactivation.

EXPERIMENTS

The synthesis of a novel hydantoin-functionalized PVA (H-PVA-hyd) is proposed. The newly synthesized H-PVA-hyd polymer was introduced in the formulation of H-PVA-based cryogels. To promote the cryogelation of the systems we exploited phase-separation mechanisms employing either a PVA carrying residual acetate groups (L-PVA) or starch as phase-segregating components. The permanence of the biocidal functionality after swelling was investigated via proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) microscopy. The activated H-PVA-hyd cryogels have been tested against bacteria with amylolytic activity (Bacillus subtilis) and the outcomes were analyzed by direct observation via confocal laser scanning microscopy (CLSM).

FINDINGS

The cryogels containing starch resulted in being the most effective (up to 90% bacterial killing), despite carrying a lower amount of hydantoin groups than their starch-free counterparts, suggesting that their improved efficacy relies on a "Trojan Horse" type of mechanism.

Indocyanine green-loaded platelet activated by photodynamic and photothermal effects for selective control of wound repair

OBJECTIVE

Prompt and effective wound repair is an essential strategy to promote recovery and prevent infection in patients with various types of trauma. Platelets can release a variety of growth factors upon activation to facilitate revascularization and tissue repair, provided that their activation is uncontrollable. The present study is designed to explore the selective activation of platelets by photodynamic and photothermal effects (PDE/PTE) as well as the trauma repair mediated by PDE/PTE.

MATERIALS AND METHODS

In the current research, platelets were extracted from the blood of mice. Indocyanine green (ICG) was applied to induce PDE/PTE. The uptake of ICG by platelets was detected by laser confocal microscopy and flow cytometry. The cellular integrity was measured by microscopy. The reactive oxygen species (ROS) generation and temperature of platelets were assayed by 2,7-Dichlorodihydrofluorescein diacetate (DCFH-DA) and temperature detector. The activation of platelets was measured by western blots (WB), dynamic light scattering (DLS), and scanning electron microscopy (SEM). The release of growth factor was detected by enzyme-linked immuno sorbent assay (Elisa), wherein the in vitro cell proliferation was investigated by 5-Ethynyl-2'-deoxyuridine (EDU) assay. The wound infection rates model and histological examination were constructed to assay the ICG-loaded platelet-mediated wound repair.

RESULTS

Platelets could load with ICG, a kind of photodynamic and photothermal agent, as carriers and remain intact. Near-infrared (NIR) laser irradiation of ICG-loaded platelets (ICG@PLT) facilitated higher temperature and ROS generation, which immediately activated ICG@PLT, as characterized by increased membrane p-selectin (CD62p), cyclooxygenase-2 (COX-2), thromboxane A2 receptor (TXA2R) expression, elevated hydrated particle size, and prominent aggregation in platelets. Further investigation revealed that massive insulin-like growth factor (IGF) and platelet-derived growth factor (PDGF) were released from the activated ICG@PLT, which also promoted the proliferation of endothelial cells and keratinocytes in co-culture. In consequence, activated platelets and increased neovascularization could be observed in rats with wound infection treated by ICG@PLT in the presence of NIR. More impressively, the hydrogel containing ICG@PLT accelerated wound healing and suppressed inflammation under NIR, exhibiting excellent wound repair properties.

CONCLUSION

Taken together, the current work identified that platelets could be activated by PDE/PTE and thereby release growth factor, potentiating wound repair in a controlled manner.

Consensus on the treatment of second-degree burn wounds (2024 edition)

Second-degree burns are the most common type of burn in clinical practice and hard to manage. Their treatment requires not only a consideration of the different outcomes that may arise from the dressing changes or surgical therapies themselves but also an evaluation of factors such as the burn site, patient age and burn area. Meanwhile, special attention should be given to the fact that there is no unified standard or specification for the diagnosis, classification, surgical procedure, and infection diagnosis and grading of second-degree burn wounds. This not only poses great challenges to the formulation of clinical treatment plans but also significantly affects the consistency of clinical studies. Moreover, currently, there are relatively few guidelines or expert consensus for the management of second-degree burn wounds, and no comprehensive and systematic guidelines or specifications for the treatment of second-degree burns have been formed. Therefore, we developed the Consensus on the Treatment of Second-Degree Burn Wounds (2024 edition), based on evidence-based medicine and expert opinion. This consensus provides specific recommendations on prehospital first aid, nonsurgical treatment, surgical treatment and infection treatment for second-degree burns. The current consensus generated a total of 58 recommendations, aiming to form a standardized clinical treatment plan.

In vitro prevention and inactivation of biofilms using controlled-release iodine foam dressings for wound healing

Microbial biofilms are a major hindrance in the wound healing process, prolonging the inflammatory response phase, thus making them a target in treatment. The aim of this study is to assess the antibacterial properties of commercially available wound dressings, of various material composition and antibacterial agents, towards multiple in vitro microbial and biofilm models. A variety of in vitro microbial and biofilm models were utilised to evaluate the ability of wound dressing materials to sequester microbes, prevent dissemination and manage bioburden. Sequestering and dissemination models were used to evaluate the ability of wound dressing materials to prevent the biofilm-forming bacterium, Pseudomonas aeruginosa, from migrating through dressing materials over a 24-72 h challenge period. Additionally, Centre for Disease Control (CDC) Bioreactor and Drip Flow models were used to evaluate antibacterial killing efficacy towards established P. aeruginosa and Staphylococcus aureus biofilms using more challenging, wound-like models. Controlled-release iodine foam and silver-impregnated carboxymethylcellulose (CMC) wound dressing materials demonstrated potent biofilm management properties in comparison to a methylene blue and gentian violet-containing foam dressing. Both the iodine-containing foam and silver-impregnated CMC materials effectively prevented viable P. aeruginosa dissemination for up to 72 h. In addition, the controlled-release iodine foam and silver-impregnated CMC materials reduced P. aeruginosa bioburden in the Drip Flow model. The controlled-release iodine foam demonstrated superiority in the CDC Bioreactor model, as both the silver- and iodine-containing materials reduced S. aureus to the limit of detection, but P. aeruginosa growth was only completely reduced by controlled-release iodine foam dressing materials. The data generated within the in vitro biofilm models supports the clinical data available in the public domain for the implementation of iodine foam dressings for effective biofilm management and control in wound care.

Metallic elements combine with herbal compounds upload in microneedles to promote wound healing: a review

Wound healing is a dynamic and complex restorative process, and traditional dressings reduce their therapeutic effectiveness due to the accumulation of drugs in the cuticle. As a novel drug delivery system, microneedles (MNs) can overcome the defect and deliver drugs to the deeper layers of the skin. As the core of the microneedle system, loaded drugs exert a significant influence on the therapeutic efficacy of MNs. Metallic elements and herbal compounds have been widely used in wound treatment for their ability to accelerate the healing process. Metallic elements primarily serve as antimicrobial agents and facilitate the enhancement of cell proliferation. Whereas various herbal compounds act on different targets in the inflammatory, proliferative, and remodeling phases of wound healing. The interaction between the two drugs forms nanoparticles (NPs) and metal-organic frameworks (MOFs), reducing the toxicity of the metallic elements and increasing the therapeutic effect. This article summarizes recent trends in the development of MNs made of metallic elements and herbal compounds for wound healing, describes their advantages in wound treatment, and provides a reference for the development of future MNs.

In Vivo Acute Toxicity and Therapeutic Potential of a Synthetic Peptide, DP1 in a Staphylococcus aureus Infected Murine Wound Excision Model

Bacterial infections at the surgical sites are one of the most prevalent skin infections that impair the healing mechanism. They account for about 20% of all types of infections and lead to approximately 75% of surgical-site infection-associated mortality. Several antibiotics, such as cephalosporins, fluoroquinolones, quinolones, penicillin, sulfonamides, etc., that are used to treat such wound infections not only counter infections but also disrupt the normal flora. Moreover, antibiotics, when used for a prolonged duration, may impair the formation of new blood vessels, delay collagen production, or inhibit the migration of certain cells involved in wound repair, leading to an impaired healing process. Therefore, there is a dire need for alternate therapeutic approaches against such infections. Antimicrobial peptides have gained considerable attention as a promising strategy to counter these pathogens and prevent the spread of infection. Recently, we have reported a designed peptide, DP1, and its broad-spectrum in vitro antimicrobial activity against Gram-positive and Gram-negative bacteria. In the present study, in vivo acute toxicity of DP1 was evaluated and even at a high dose (20 mg/kg body weight) of DP1, a 100% survival of mice was observed. Subsequently, a Staphylococcus aureus-infected murine wound excision model was established to assess the wound healing efficacy of DP1. The study revealed significant wound healing vis-a-vis attenuated S. aureus bioburden at the wound site and also controlled the oxidative stress depicting anti-oxidant activity as well. Healing of the infected wounds was also verified by histopathological examination. Based on the results of this study, it can be concluded that DP1 improves wound resolution despite infections and promotes the healing mechanism. Hence, DP1 holds compelling potential as a novel antimicrobial drug that requires further explorations in clinical platforms.

Eco-Friendly Cellulose-Based Nonionic Antimicrobial Polymers with Excellent Biocompatibility, Nonleachability, and Polymer Miscibility

This study aims to prepare natural biomass-based nonionic antimicrobial polymers with excellent biocompatibility, nonleachability, antimicrobial activity, and polymer miscibility. Two new cellulose-based nonionic antimicrobial polymers (MIPA and MICA) containing many terminal indole groups were synthesized using a sustainable one-pot method. The structures and properties of the nonionic antimicrobial polymers were characterized using nuclear magnetic resonance hydrogen spectroscopy (1H NMR), infrared spectroscopy (FTIR), wide-angle X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), gel chromatography (GPC), and other analytical techniques. The results showed that microcrystalline cellulose (MCC) molecules combined with indole derivatives through an esterification reaction to produce MICA and MIPA. The crystallinity of the prepared MICA and MIPA molecules decreased after MCC modification; their morphological structure changed from short fibrous to granular and showed better thermal stability and solubility. The paper diffusion method showed that both nonionic polymers had good bactericidal effects against the two common pathogenic bacteria Escherichia coli (E. coli, inhibition zone diameters >22 mm) and Staphylococcus aureus (S. aureus, inhibition zone diameters >38 mm). Moreover, MICA and MIPA showed good miscibility with biodegradable poly(vinyl alcohol) (PVA), and the miscible cellulose-based composite films (PVA-MICA and PVA-MIPA) showed good phase compatibility, light transmission, thermal stability (maximum thermal decomposition temperature >300 °C), biocompatibility, biological cell activity (no cytotoxicity), nonleachability, antimicrobial activity, and mechanical properties (maximum fracture elongation at >390%).

Nanocurcumin and viable Lactobacillus plantarum based sponge dressing for skin wound healing

Curcumin loaded solid lipid nanoparticles (CSLNs) and probiotic (Lactobacillus plantarum UBLP-40; L. plantarum) were currently co-incorporated into a wound dressing. The combination with manifold anti-inflammatory, anti-infective, analgesic, and antioxidant properties of both curcumin and L. plantarum will better manage complex healing process. Recent reports indicate that polyphenolics like curcumin improve probiotic effects. Curcumin was nanoencapsulated (CSLNs) to improve its bioprofile and achieve controlled release on the wound bed. Bacteriotherapy (probiotic) is established to promote wound healing via antimicrobial activity, inhibition of pathogenic toxins, immunomodulation, and anti-inflammatory actions. Combination of CSLNs with probiotic enhanced (560%) its antimicrobial effects against planktonic cells and biofilms of skin pathogen, Staphylococcus aureus 9144. The sterile dressing was devised with selected polymers, and optimized for polymer concentration, and dressing characteristics using a central composite design. It exhibited a swelling ratio of 412 ± 36%, in vitro degradation time of 3 h, optimal water vapor transmission rate of 1516.81 ± 155.25 g/m2/day, high tensile strength, low-blood clotting index, case II transport, and controlled release of curcumin. XRD indicated strong interaction between employed polymers. FESEM revealed a porous sponge like meshwork embedded with L. plantarum and CSLNs. It degraded and released L. plantarum, which germinated in the wound bed. The sponge was stable under refrigerated conditions for up to six months. No translocation of probiotic from wound to the internal organs confirmed safety. The dressing exhibited faster wound closure and lowered bioburden in the wound area in mice. This was coupled with a decrease in TNF-α, MMP-9, and LPO levels; and an increase in VEGF, TGF-β, and antioxidant enzymes such as catalase and GSH, establishing multiple healing pathways. Results were compared with CSLNs and probiotic-alone dressings. The dressing was as effective as the silver nanoparticle-based marketed hydrogel dressing; however, the cost and risk of developing resistance would be much lower currently.

Current status and progress in research on dressing management for diabetic foot ulcer

Diabetic foot ulcer (DFU) is a major complication of diabetes and is associated with a high risk of lower limb amputation and mortality. During their lifetime, 19%-34% of patients with diabetes can develop DFU. It is estimated that 61% of DFU become infected and 15% of those with DFU require amputation. Furthermore, developing a DFU increases the risk of mortality by 50%-68% at 5 years, higher than some cancers. Current standard management of DFU includes surgical debridement, the use of topical dressings and wound decompression, vascular assessment, and glycemic control. Among these methods, local treatment with dressings builds a protective physical barrier, maintains a moist environment, and drains the exudate from DFU wounds. This review summarizes the development, pathophysiology, and healing mechanisms of DFU. The latest research progress and the main application of dressings in laboratory and clinical stage are also summarized. The dressings discussed in this review include traditional dressings (gauze, oil yarn, traditional Chinese medicine, and others), basic dressings (hydrogel, hydrocolloid, sponge, foam, film agents, and others), bacteriostatic dressings, composite dressings (collagen, nanomaterials, chitosan dressings, and others), bioactive dressings (scaffold dressings with stem cells, decellularized wound matrix, autologous platelet enrichment plasma, and others), and dressings that use modern technology (3D bioprinting, photothermal effects, bioelectric dressings, microneedle dressings, smart bandages, orthopedic prosthetics and regenerative medicine). The dressing management challenges and limitations are also summarized. The purpose of this review is to help readers understand the pathogenesis and healing mechanism of DFU, help physicians select dressings correctly, provide an updated overview of the potential of biomaterials and devices and their application in DFU management, and provide ideas for further exploration and development of dressings. Proper use of dressings can promote DFU healing, reduce the cost of treating DFU, and reduce patient pain.

Immobilization of Bacteriophages in Ex Tempore Hydrogel for the Treatment of Burn Wound Infection

The resistance of bacteria to antibiotics is a major problem for anti-bacterial therapy. This problem may be solved by using bacteriophages-viruses that can attack and destroy bacteria, including antibiotic-resistant ones. In this article, the authors compared the efficacy of topical bacteriophage therapy and systemic antibiotic therapy in the treatment of wound infections caused by ESKAPE pathogens in patients with limited (less than 5% of the body surface) full-thickness burns. Patients in the study group (n = 30) were treated with PVA-based hydrogel dressings saturated ex tempore with a bacteriophage suspension characterized by its lytic activity against the bacteria colonizing the wound. Patients in the control group (n = 30) were treated using etiotropic systemic antibiotic therapy, and the wounds were covered with gauze bandages soaked in an aqueous solution of povidone-iodine. An assessment of the decrease in the level of bacterial contamination of the recipient wounds in both groups was conducted after 7 days, and after that, free skin grafting was performed. On day 14 after free skin grafting, patients in both groups underwent incisional biopsy. The study group demonstrated an increase in the indices of proliferative activity (Ki-67), and angiogenesis (CD-31, VEGF) in the area of engraftment of the split-thickness skin grafts. The results indicate that PVA-based hydrogel wound dressings can be used as bacteriophage carriers for local antimicrobial therapy ahead of free skin grafting.

Experimental and clinical evidence for DACC-coated dressings: an update

OBJECTIVE

To update the evidence in relation to the use of dialkylcarbamoyl chloride (DACC)-coated wound dressings in the prevention, treatment and management of wounds.

METHOD

PubMed and PubMed Central databases were searched to identify articles published since 2020 describing the experimental and clinical evidence for DACC-coated dressings, and their antimicrobial effect, as well as their impact on the prevention and treatment of infected wounds. The identified articles were then narratively reviewed.

RESULTS

The search yielded 113 articles (plus references from ad hoc sources), of which nine met the inclusion criteria. Of the nine included studies, five related to clinical aspects and four were laboratory studies.

CONCLUSION

A number of new studies have provided further evidence for the mode of action of the antimicrobial effect of DACC-coated dressings and its wide spectrum effect (including World Health Organization-prioritised microorganisms). Additional clinical studies have provided evidence of new applications, such as in treating wounds in paediatric patients, and extended the evidence relating to their use in treating surgical site infections. Evidence also shows that DACC-coated wound dressings can aid in the binding of biofilms, and how this technology can align and support antimicrobial stewardship in the prevention of antimicrobial resistance.

Hydrogel-Containing Biogenic Silver Nanoparticles: Antibacterial Action, Evaluation of Wound Healing, and Bioaccumulation in Wistar Rats

Wound infections are feared complications due to their potential to increase healthcare costs and cause mortality since multidrug-resistant bacteria reduce treatment options. This study reports the development of a carbomer hydrogel containing biogenic silver nanoparticles (bioAgNPs) and its effectiveness in wound treatment. This hydrogel showed in vitro bactericidal activity after 2 h, according to the time-kill assay. It also reduced bacterial contamination in rat wounds without impairing their healing since the hydrogel hydrophilic groups provided hydration for the injured skin. The high number of inflammatory cells in the first days of the skin lesion and the greater degree of neovascularization one week after wound onset showed that the healing process occurred normally. Furthermore, the hydrogel-containing bioAgNPs did not cause toxic silver accumulation in the organs and blood of the rats. This study developed a bioAgNP hydrogel for the treatment of wounds; it has a potent antimicrobial action without interfering with cicatrization or causing silver bioaccumulation. This formulation is effective against bacteria that commonly cause wound infections, such as Pseudomonas aeruginosa and Staphylococcus aureus, and for which new antimicrobials are urgently needed, according to the World Health Organization's warning.

The role of negative pressure wound therapy with instillation and dwell time in the treatment of deep sternal wound infections-A retrospective cohort study

Background and Aims

Negative pressure wound therapy (NPWT) has gained a central role in the treatment of deep sternal wound infections (DSWIs) after median thoracotomy. Our study aims at proving the safety of using NPWT with instillation and dwell time (NPWTi-d) in the treatment of DSWI.

Methods

We retrospectively evaluated the patients who were treated at our institution between March 2018 and November 2021 for DSWI after radical sternectomy using NPWT or NPWTi-d. The NPWTi-d was applied to start the first postoperative day using 75 mmHg negative pressure for 3 h, followed by instillation of sodium hypochlorite <0.08% with a 3-min dwell time.

Results

The NPWTi-d group showed a shorter length of stay (29.39 ± 12.09 vs. 39.54 ± 17.07 days; p = 0.049), a shorter elapsed time between the debridement and the flap coverage (7.18 ± 4.27 vs. 11.86 ± 7.7 days; p = 0.003) and less operative or nonoperative dressing changes (1.73 ± 1.14 vs. 2.68 ± 56; p < 0.001). The in-hospital mortality was 8.2%, with no significant differences between the two groups (p = 1).

Conclusion

NPWTi-d can be safely employed in the treatment of DSWI. Further prospective randomized studies need to establish the role of NPWTi-d in the control of infection and biofilm as well as in wound healing.

Application of cold atmospheric microwave plasma as an adjunct therapy for wound healing in dogs and cats

BACKGROUND

Cold atmospheric plasma is a novel innovative approach for wound care, and it is currently underrepresented in veterinary medicine.

OBJECTIVES

To investigate the efficacy and safety of using cold atmospheric microwave plasma (CAMP) as an adjunct therapy for wound healing in dogs and cats.

METHODS

Wound healing outcomes were retrospectively analyzed using clinical records of client-owned dogs and cats who were first managed through standard wound care alone (pre-CAMP period) and subsequently via CAMP therapy (CAMP period). The degree of wound healing was estimated based on wound size and a modified wound scoring system.

RESULTS

Of the 27 acute and chronic wounds included in the analysis, 81.48% showed complete healing after the administration of CAMP as an adjunct therapy to standard care. Most wounds achieved complete healing in < 5 weeks. Compared with the pre-CAMP period, the rate of wound healing significantly increased every week in the CAMP period in terms of in wound size (first week, p < 0.001; second week, p = 0.012; third week, p < 0.001) and wound score (first week, p < 0.001; second week, p < 0.001; third week, p = 0.001). No adverse events were noted except for mild discomfort and transient erythema.

CONCLUSIONS

CAMP is a well-tolerated therapeutic option with immense potential to support the treatment of wounds of diverse etiology in small animal practice. Further research is warranted to establish specific criteria for CAMP treatment according to wound characteristics.

Alginate-Based Materials Loaded with Nanoparticles in Wound Healing

Alginate is a naturally derived polysaccharide widely applied in drug delivery, as well as regenerative medicine, tissue engineering and wound care. Due to its excellent biocompatibility, low toxicity, and the ability to absorb a high amount of exudate, it is widely used in modern wound dressings. Numerous studies indicate that alginate applied in wound care can be enhanced with the incorporation of nanoparticles, revealing additional properties beneficial in the healing process. Among the most extensively explored materials, composite dressings with alginate loaded with antimicrobial inorganic nanoparticles can be mentioned. However, other types of nanoparticles with antibiotics, growth factors, and other active ingredients are also investigated. This review article focuses on the most recent findings regarding novel alginate-based materials loaded with nanoparticles and their applicability as wound dressings, with special attention paid to the materials of potential use in the treatment of chronic wounds.

Novel micropore particle technology for spinal cord injury chronic wound healing: a new paradigm?

Current management of chronic wounds involves regular wound cleaning, antiseptic dressings and, when indicated, antimicrobials. Micropore particle technology (MPPT) is a novel concept for wound healing, aiming to bolster the action of the immune system by disrupting the wound biofilm and restoring the microbiome. Amicapsil is the first MPPT product licensed for clinical use. Patients with a spinal cord injury (SCI) are more likely to develop chronic wounds due to downregulation in their immune response increasing the risk of a minor wound, such as pressure sore, developing into large, non-healing wounds. At the Defence Medical Rehabilitation Centre (DMRC) Stanford Hall, patients with SCI often have chronic wounds causing pain, becoming infected and preventing full engagement with effective rehabilitation. We report on the first case of treatment with Amicapsil at the DMRC Stanford Hall and review MPPT as a potential new paradigm for the treatment of wound healing.

Dioclea violacea lectin increases the effect of neomycin against multidrug-resistant strains and promotes the purification of the antibiotic in immobilized lectin column

DVL is a Man/Glc-binding lectin from Dioclea violacea seeds that has the ability to interact with the antibiotic gentamicin. The present work aimed to evaluate whether the DVL has the ability to interact with neomycin via CRD and to examine the ability of this lectin to modulate the antibiotic effect of neomycin against multidrug-resistant strains (MDR). The hemagglutinating activity test revealed that neomycin inhibited the hemagglutinating activity of DVL with a minimum inhibitory concentration of 50 mM, indicating that the antibiotic interacts with DVL via the carbohydrate recognition domain (CRD). DVL immobilized on cyanogen bromide-activated Sepharose® 4B bound 41 % of the total neomycin applied to the column, indicating that the DVL-neomycin interaction is efficient for purification processes. Furthermore, the minimum inhibitory concentrations (MIC) obtained for DVL against all strains studied were not clinically relevant. However, when DVL was combined with neomycin, a significant increase in antibiotic activity was observed against S. aureus and P. aeruginosa. These results demonstrate the first report of lectin-neomycin interaction, indicating that immobilized DVL has the potential to isolate neomycin by affinity chromatography. Moreover, DVL increased the antibiotic activity of neomycin against MDR, suggesting that it is a potent adjuvant in the treatment of infectious diseases.

Controlled Delivery of Vancomycin from Collagen-tethered Peptide Vehicles for the Treatment of Wound Infections

Despite the great promise of antibiotic therapy in wound infections, antibiotic resistance stemming from frequent dosing diminishes drug efficacy and contributes to recurrent infection. To identify improvements in antibiotic therapies, new antibiotic delivery systems that maximize pharmacological activity and minimize side effects are needed. In this study, we developed elastin-like peptide and collagen-like peptide nanovesicles (ECnVs) tethered to collagen-containing matrices to control vancomycin delivery and provide extended antibacterial effects against methicillin-resistant Staphylococcus aureus (MRSA). We observed that ECnVs showed enhanced entrapment efficacy of vancomycin by 3-fold as compared to liposome formulations. Additionally, ECnVs enabled the controlled release of vancomycin at a constant rate with zero-order kinetics, whereas liposomes exhibited first-order release kinetics. Moreover, ECnVs could be retained on both collagen-fibrin (co-gel) matrices and collagen-only matrices, with differential retention on the two biomaterials resulting in different local concentrations of released vancomycin. Overall, the biphasic release profiles of vancomycin from ECnVs/co-gel and ECnVs/collagen more effectively inhibited the growth of MRSA for 18 and 24 h, respectively, even after repeated bacterial inoculation, as compared to matrices containing free vancomycin, which just delayed the growth of MRSA. Thus, this newly developed antibiotic delivery system exhibited distinct advantages for controlled vancomycin delivery and prolonged antibacterial activity relevant to the treatment of wound infections.

A new complex of silver(I) with probenecid: Synthesis, characterization, and studies of antibacterial and extended spectrum β-lactamases (ESBL) inhibition activities

This article describes the in vitro antibacterial and β-lactamase inhibition of a novel silver(I) complex with the sulfonamide probenecid (Ag-PROB). The formula Ag₂C₂₆H₃₆N2O₈S₂·2H₂O for the Ag-PROB complex was proposed based on elemental analysis. High-resolution mass spectrometric studies revealed the existence of the complex in its dimeric form. Infrared, nuclear magnetic resonance spectroscopies and Density Functional Theory calculations indicated a bidentate coordination of probenecid to the silver ions by the oxygen atoms of the carboxylate. In vitro antibacterial activities of Ag-PROB showed significant growth inhibitory activity over Mycobacterium tuberculosis, S. aureus, and P. aeruginosa PA01biofilm-producers, B. cereus, and E. coli. The Ag-PROB complex was active over multi-drug resistant of uropathogenic E. coli extended spectrum β-lactamases (ESBL) producing (EC958 and BR43), enterohemorrhagic E. coli (O157:H7) and enteroaggregative E. coli (O104:H4). Ag-PROB was able to inhibit CTX-M-15 and TEM-1B ESBL classes, at concentrations below the minimum inhibitory concentration for Ag-PROB, in the presence of ampicillin (AMP) concentration in which EC958 and BR43 bacteria were resistant in the absence of Ag-PROB. These results indicate that, in addition to ESBL inhibition, there is a synergistic antibacterial effect between AMP and the Ag-PROB. Molecular docking results revealed potential key residues involved in interactions between Ag-PROB, CTX-M-15 and TEM1B, suggesting the molecular mechanism of the ESBL inhibition. The obtained results added to the absence of mutagenic activity and low cytotoxic activity over non-tumor cell of the Ag-PROB complex open a new perspective for future in vivo tests demonstrating its potential of use as an antibacterial agent.

Antimicrobial Properties of TiNbSn Alloys Anodized in a Sulfuric Acid Electrolyte

TiNbSn alloy is a high-performance titanium alloy which is biosafe, strong, and has a low Young's modulus. TiNbSn alloy has been clinically applied as a material for orthopedic prosthesis. Anodized TiNbSn alloys with acetic and sulfuric acid electrolytes have excellent biocompatibility for osseointegration. Herein, TiNbSn alloy was anodized in a sulfuric acid electrolyte to determine the antimicrobial activity. The photocatalytic activities of the anodic oxide alloys were investigated based on their electronic band structure and crystallinity. In addition, the cytotoxicity of the anodized TiNbSn alloy was evaluated using cell lines of the osteoblast and fibroblast lineages. The antimicrobial activity of the anodic oxide alloy was assessed according to the ISO 27447 using methicillin-susceptible Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. The anodic oxide comprised rutile and anatase titanium dioxide (TiO₂) and exhibited a porous microstructure. A well-crystallized rutile TiO₂ phase was observed in the anodized TiNbSn alloy. The methylene blue degradation tests under ultraviolet illumination exhibited photocatalytic activity. In antimicrobial tests, the anodized TiNbSn alloy exhibited robust antimicrobial activities under ultraviolet illumination for all bacterial species, regardless of drug resistance. Therefore, the anodized TiNbSn alloy can be used as a functional biomaterial with low Young's modulus and excellent antimicrobial activity.

High value valorization of lignin as environmental benign antimicrobial

Lignin is a natural aromatic polymer of p-hydroxyphenylpropanoids with various biological activities. Noticeably, plants have made use of lignin as biocides to defend themselves from pathogen microbial invasions. Thus, the use of isolated lignin as environmentally benign antimicrobial is believed to be a promising high value approach for lignin valorization. On the other hand, as green and sustainable product of plant photosynthesis, lignin should be beneficial to reduce the carbon footprint of antimicrobial industry. There have been many reports that make use of lignin to prepare antimicrobials for different applications. However, lignin is highly heterogeneous polymers different in their monomers, linkages, molecular weight, and functional groups. The structure and property relationship, and the mechanism of action of lignin as antimicrobial remains ambiguous. To show light on these issues, we reviewed the publications on lignin chemistry, antimicrobial activity of lignin models and isolated lignin and associated mechanism of actions, approaches in synthesis of lignin with improved antimicrobial activity, and the applications of lignin as antimicrobial in different fields. Hopefully, this review will help and inspire researchers in the preparation of lignin antimicrobial for their applications.

Improving the antimicrobial activity of old antibacterial drug mafenide: Schiff bases and their bioactivity targeting resistant pathogens

Background: Increasing rates of acquired resistance have justified the critical need for novel antimicrobial drugs. One viable concept is the modification of known drugs. Methods & results: 21 mafenide-based compounds were prepared via condensation reactions and screened for antimicrobial efficacy, which demonstrated promising activity against both Gram-positive and Gram-negative pathogens, pathogenic fungi and mycobacterial strains (minimum inhibitory concentrations from 3.91 μM). Importantly, they retained activity against a panel of superbugs (methicillin- and vancomycin-resistant staphylococci, enterococci, multidrug-resistant Mycobacterium tuberculosis) without any cross-resistance. Unlike mafenide, most of its imines were bactericidal. Toxicity to HepG2 cells was also investigated. Conclusion: Schiff bases were significantly more active than the parent drug, with iodinated salicylidene and 5-nitrofuran/thiophene-methylidene scaffolds being preferred in identifying the most promising drug candidates.

Managing malignant wounds in patients receiving palliative care

Malignant wounds are a complication of cancer and usually develop in patients with advanced disease. Physical symptoms associated with these wounds include pain, bleeding, exudate, malodour and pruritus, while patients may also experience various distressing psychosocial effects. The aim for nurses is to manage these physical symptoms and psychosocial effects, thus enhancing quality of life for patients and their families. This article discusses the symptoms and effects associated with malignant wounds, and explains what is involved in a wound assessment. It also outlines strategies that can be used to manage or eliminate wound-related symptoms and enhance patients' quality of life.

Polyhexamethylene biguanide and its antimicrobial role in wound healing: a narrative review

A wound offers an ideal environment for the growth and proliferation of a variety of microorganisms which, in some cases, may lead to localised or even systemic infections that can be catastrophic for the patient; the development of biofilms exacerbates these infections. Over the past few decades, there has been a progressive development of antimicrobial resistance (AMR) in microorganisms across the board in healthcare sectors. Such resistant microorganisms have arisen primarily due to the misuse and overuse of antimicrobial treatments, and the subsequent ability of microorganisms to rapidly change and mutate as a defence mechanism against treatment (e.g., antibiotics). These resistant microorganisms are now at such a level that they are of grave concern to the World Health Organization (WHO), and are one of the leading causes of illness and mortality in the 21st century. Treatment of such infections becomes imperative but presents a significant challenge for the clinician in that treatment must be effective but not add to the development of new microbes with AMR. The strategy of antimicrobial stewardship (AMS) has stemmed from the need to counteract these resistant microorganisms and requires that current antimicrobial treatments be used wisely to prevent amplification of AMR. It also requires new, improved or alternative methods of treatment that will not worsen the situation. Thus, any antimicrobial treatment should be effective while not causing further development of resistance. Some antiseptics fall into this category and, in particular, polyhexamethylene hydrochloride biguanide (PHMB) has certain characteristics that make it an ideal solution to this problem of AMR, specifically within wound care applications. PHMB is a broad-spectrum antimicrobial that kills bacteria, fungi, parasites and certain viruses with a high therapeutic index, and is widely used in clinics, homes and industry. It has been used for many years and has not been shown to cause development of resistance; it is safe (non-cytotoxic), not causing damage to newly growing wound tissue. Importantly there is substantial evidence for its effective use in wound care applications, providing a sound basis for evidence-based practice. This review presents the evidence for the use of PHMB treatments in wound care and its alignment with AMS for the prevention and treatment of wound infection.

Cedrus deodara: In Vivo Investigation of Burn Wound Healing Properties

Objective

Cedrus deodara (Roxb. Ex Lamb.) G. Don possesses various biological activities, which have been documented in modern and traditional medicine. In this study, burn wound healing activity of the methanol extract of C. deodara wood was evaluated via a burn wound model in Wistar rats.

Methods

The methanol extract of C. deodara was evaluated for the contents of phenolic compounds, flavonoids, and tannins. Also, its antioxidant activity was determined using the DPPH assay. Then, a topical ointment containing the methanol extract of C. deodara (10%) was used to evaluate the healing effects on a model of second-degree thermal burn in 4 groups of 7 rats within 21 days. In this respect, average wound surface area, wound closure, and various histological features were examined.

Results

Our findings revealed that the wounds treated with the methanol extract of C. deodara showed higher wound contraction (33.6, 87.1, and 93.4% on days 7, 14, and 21, respectively) compared with the positive control (27.6, 80.7, and 88.3% on days 7, 14, and 21, respectively) and the negative control (20.1, 77.9, and 80.2% on days 7, 14, and 21, respectively). According to the results from epitheliogenesis score, the number of inflammatory cells, neovascularization, and collagen density, good burn wound healing activity of the methanol extract of C. deodarawas demonstrated.

Conclusion

Using the methanol extract of C. deodara in an ointment formulation can be developed to prevent or reduce burn injury progression.

Antibacterial smart hydrogels: New hope for infectious wound management

Millions of people die annually due to uncured wound infections. Healthcare systems incur high costs to treat wound infections. Tt is predicted to become more challenging due to the rise of multidrug-resistant conditions. During the last decades, smart antibacterial hydrogels could attract attention as a promising solution, especially for skin wound infections. These antibacterial hydrogels are termed 'smart' due to their response to specific physical and chemical environmental stimuli. To deliver different drugs to particular sites in a controlled manner, various types of crosslinking strategies are used in the manufacturing process. Smart hydrogels are designed to provide antimicrobial agents to the infected sites or are built from polymers with inherent disinfectant properties. This paper aims to critically review recent pre-clinical and clinical advances in using smart hydrogels against skin wound infections and propose the next best thing for future trends. For this purpose, an introduction to skin wound healing and disease is presented and intelligent hydrogels responding to different stimuli are introduced. Finally, the most promising investigations are discussed in their related sections. These studies can pave the way for producing new biomaterials with clinical applications.

Application of antimicrobial, potential hazard and mitigation plans

The tremendous rise in the consumption of antimicrobial products had aroused global concerns, especially in the midst of pandemic COVID-19. Antimicrobial resistance has been accelerated by widespread usage of antimicrobial products in response to the COVID-19 pandemic. Furthermore, the widespread use of antimicrobial products releases biohazardous substances into the environment, endangering the ecology and ecosystem. Therefore, several strategies or measurements are needed to tackle this problem. In this review, types of antimicrobial available, emerging nanotechnology in antimicrobial production and their advanced application have been discussed. The problem of antimicrobial resistance (AMR) due to antibiotic-resistant bacteria (ARB)and antimicrobial resistance genes (AMG) had become the biggest threat to public health. To deal with this problem, an in-depth discussion of the challenges faced in antimicrobial mitigations and potential alternatives was reviewed.

Inorganic nanomaterials for intelligent photothermal antibacterial applications

Antibiotics are currently the main therapeutic agent for bacterial infections, but they have led to bacterial resistance, which has become a worldwide problem that needs to be addressed. The emergence of inorganic nanomaterials provides a new opportunity for the prevention and treatment of bacterial infection. With the continuous development of nanoscience, more and more inorganic nanomaterials have been used to treat bacterial infections. However, single inorganic nanoparticles (NPs) are often faced with problems such as large dosage, strong toxic and side effects, poor therapeutic effect and so on, so the combination of inorganic nano-materials and photothermal therapy (PTT) has become a promising treatment. PTT effectively avoids the problem of bacterial drug resistance, and can also reduce the dosage of inorganic nanomaterials to a certain extent, greatly improving the antibacterial effect. In this paper, we summarize several common synthesis methods of inorganic nanomaterials, and discuss the advantages and disadvantages of several typical inorganic nanomaterials which can be used in photothermal treatment of bacterial infection, such as precious metal-based nanomaterials, metal-based nanomaterials and carbon-based nanomaterials. In addition, we also analyze the future development trend of the remaining problems. We hope that these discussions will be helpful to the future research of near-infrared (NIR) photothermal conversion inorganic nanomaterials.

Extracts of Rheum palmatum and Aloe vera Show Beneficial Properties for the Synergistic Improvement of Oral Wound Healing

Various local and systemic factors compromise oral wound healing and may lead to wound dehiscence, inflammation, or ulcers. Currently, there is a lack of topical therapeutical options. Thus, this study aimed to investigate the effect of Aloe vera (AV) and Rheum palmatum root (RPR) on oral wound healing capacity in vitro. The effect of AV and RPR on human primary fibroblast viability and migration was studied by measuring metabolic activity and gap closure in a scratch assay. Furthermore, cell cycle distribution and cytoskeletal features were analyzed. Antimicrobial activity against the oral pathogen Porphyromonas gingivalis was evaluated by broth microdilution assay. AV and RPR increased fibroblast migration after single agent treatment. Synergistic effects of the plant extract combination were observed regarding cellular migration which were confirmed by calculation of the phenomenological combination index (pCI), whereas the cell cycle distribution was not influenced. Furthermore, the combination of AV and RPR showed synergistic antibacterial effects as determined by the fractional inhibitory concentration index. This study demonstrated that the combination of AV and RPR can promote the migration of human primary fibroblasts in vitro and exert antimicrobial efficacy against P. gingivalis, suggesting these compounds for the topical treatment of wound healing disorders.

Robbing Peter to Pay Paul: Chlorhexidine gluconate demonstrates short-term efficacy and long-term cytotoxicity

Wound cleansing agents are routine in wound care and preoperative preparation. Antiseptic activity intends to prevent contaminating microbes from establishing an infection while also raising concerns of cytotoxicity and delayed wound healing. We evaluated the cytotoxicity of five clinically used wound cleaning agents (saline, povidone iodine, Dove® and Dial® soaps, and chlorhexidine gluconate [CHG]) using both an ex vivo and in vivo human skin xenograft mouse model, in contrast to classical in vitro models that lack the structural and compositional heterogeneity of human skin. We further established an ex vivo wound contamination model inoculated with ~100 cells of Pseudomonas aeruginosa or Staphylococcus aureus to evaluate antimicrobial efficacy. Scanning electron microscopy and confocal microscopy were used to evaluate phenotypic and spatial characteristics of bacterial cells in wound tissue. CHG significantly reduced metabolic activity of the skin explants, while all treatments except saline affected local cellular viability. CHG cytotoxicity persisted and progressed over 14 days, impairing wound healing in vivo. Within the contamination model, CHG treatment resulted in a significant reduction of P. aeruginosa wound surface counts at 24 h post-treatment. However, this effect was transient and serial application of CHG had no effect on both P. aeruginosa or S. aureus microbial growth. Microscopy revealed that viable cells of P. aeruginosa reside deep within wound tissue post-CHG application, likely serving as a reservoir to re-populate the tissue to a high bioburden. We reveal concerning cytotoxicity and limited antimicrobial activity of CHG in human skin using clinically relevant models, with the ability to resolve spatial localization and temporal dynamics of tissue viability and microbial growth.

Engineering Antimicrobial Polymer Nanocomposites: In Situ Synthesis, Disruption of Polymicrobial Biofilms, and In Vivo Activity

The increasing incidence of microbial infections and a limited arsenal of effective antibacterial and antifungal agents have entailed the need for new broad-spectrum therapeutics. Polymer-inorganic nanocomposites have emerged as an integral choice of antimicrobials but are limited by complicated synthesis, narrow-spectrum activity, and poor in vivo efficacy. Herein, chloride counterions of a nontoxic, moderately antibacterial polymer have been explored for in situ nanoprecipitation-based synthesis of water-soluble polymer-silver chloride nanocomposites. With the controlled release of silver ions, the nanocomposites were highly active against multidrug-resistant bacteria as well as fluconazole-resistant fungi. Alongside the elimination of metabolically inactive bacterial cells, the nanocomposites disrupted polymicrobial biofilms, unlike antibiotics and only silver-based ointments. This underlined the role of the engineered composite design, where the polymer interacted with the biofilm matrix, facilitating the penetration of nanoparticles to kill microbes. Further, the nanocomposite diminished Pseudomonas aeruginosa burden in mice skin infection (>99.9%) with no dermal toxicity proving its potential for clinical translation.

What COVID-19 taught us: New opportunities and pathways from telemedicine and novel antiseptics in wound healing

The COVID-19 pandemic deeply impacted the capacity of the health systems to maintain preventive and curative services, especially for the most vulnerable populations. During the pandemic, the wound healing centres in Italy assisted a significant reduction of the frequency of their hospital admission, since only urgencies, such as severe infections or wound haemorrhagic complications, were allowed to the hospital. The aim of this multidisciplinary work is to highlight the importance of a new pathway of wound care with patient-based therapeutic approach, tailored treatments based on the characteristics of the wound and fast tracks focused on the outpatient management, reserving hospital assessment only for patients with complicated or complex wounds. This analysis highlights the point that patients with chronic wounds need to be critically evaluated in order to find the best and most appropriate care pathway, which should vary according to the patient and, especially, to the characteristics of the wound. Moreover, the most adequate topic antiseptic should be started as soon as possible. An appropriate and correct management of the wound care will allow to link the knowledge based on years of clinical practice with the new challenges and the need to visit patients remotely, when possible.