Treatment Strategies for Infected Wounds

The potential of functionalized dressing releasing flavonoids facilitates scar-free healing

Scars are pathological marks left after an injury heals that inflict physical and psychological harm, especially the great threat to development and aesthetics posed by oral and maxillofacial scars. The differential expression of genes such as transforming growth factor-β, local adherent plaque kinase, and yes-related transcriptional regulators at infancy or the oral mucosa is thought to be the reason of scarless regenerative capacity after tissue defects. Currently, tissue engineering products for defect repair frequently overlook the management of postoperative scars, and inhibitors of important genes alone have negative consequences for the organism. Natural flavonoids have hemostatic, anti-inflammatory, antioxidant, and antibacterial properties, which promote wound healing and have anti-scar properties by interfering with the transmission of key signaling pathways involved in scar formation. The combination of flavonoid-rich drug dressings provides a platform for clinical translation of compounds that aid in drug disintegration, prolonged release, and targeted delivery. Therefore, we present a review of the mechanisms and effects of flavonoids in promoting scar-free regeneration and the application of flavonoid-laden dressings.

A critical review on starch-based electrospun nanofibrous scaffolds for wound healing application

Starch-based nanofibrous scaffolds exhibit a potential wound healing processes as they are cost-effective, flexible, and biocompatible. Recently, natural polymers have received greater importance in regenerative medicine, mainly in the process of healing wounds and burns due to their unique properties which also include safety, biocompatibility, and biodegradability. In this respect, starch is considered to be one of the reliable natural polymers to promote the process of wound healing at a significantly faster rate. Starch and starch-based electrospun nanofibrous scaffolds have been used for the wound healing process which includes the process of adhesion, proliferation, differentiation, and regeneration of cells. It also possesses significant activity to encapsulate and deliver biomaterials at a specific site which persuades the wound healing process at an increased rate. As the aforementioned scaffolds mimic the native extracellular matrix more closely, may help in the acceleration of wound closure, which in turn may lead to the promotion of tissue reorganization and remodeling. In-depth knowledge in understanding the properties of nanofibrous scaffolds paves a way to unfold novel methods and therapies, also to overcome challenges associated with wound healing. This review is intended to provide comprehensive information and recent advances in starch-based electrospun nanofibrous scaffolds for wound healing.

Gellan Gum in Wound Dressing Scaffolds

Several factors, such as bacterial infections, underlying conditions, malnutrition, obesity, ageing, and smoking are the most common issues that cause a delayed process of wound healing. Developing wound dressings that promote an accelerated wound healing process and skin regeneration is crucial. The properties of wound dressings that make them suitable for the acceleration of the wound healing process include good antibacterial efficacy, excellent biocompatibility, and non-toxicity, the ability to provide a moist environment, stimulating cell migration and adhesion, and providing gaseous permeation. Biopolymers have demonstrated features appropriate for the development of effective wound dressing scaffolds. Gellan gum is one of the biopolymers that has attracted great attention in biomedical applications. The wound dressing materials fabricated from gellan gum possess outstanding properties when compared to traditional dressings, such as good biocompatibility, biodegradability, non-toxicity, renewability, and stable nature. This biopolymer has been broadly employed for the development of wound dressing scaffolds in different forms. This review discusses the physicochemical and biological properties of gellan gum-based scaffolds in the management of wounds.

Optimization and characterization of a novel tea tree oil-integrated poly (ε-caprolactone)/soy protein isolate electrospun mat as a wound care system

A set of poly (ε-caprolactone)/soy protein isolate (PCL/SPI) mats with different ratios of PCL to SPI was fabricated using the electrospinning method. The mat with PCL to SPI ratio of 95:5 (PS 95:5) had the narrowest nanofibers, the highest percentage of porosity, the lowest swelling ratio, the least vapor transmission, and the slowest degradation rate among the prepared mats. The hemolysis assay indicated that all mats can be considered biocompatible biomaterials. In continue, three different weight ratios of tea tree oil (TTO) were loaded into the PS 95:5 mat. The release profiles illustrated that higher amounts of TTO could be released in an acidic environment. The antioxidant activity of the mats increased by the increase in their TTO content. The cell viability test, cell adhesion images, and live/dead assay of TTO-loaded mats affirmed that all fabricated mats were biocompatible. The scratch wound assay expressed that TTO accelerates the rate of wound closure. The TTO-loaded mats illustrated antibacterial activity against both Escherichia coli and Staphylococcus aureus bacteria. The obtained outcomes revealed that TTO-loaded PCL/SPI mats can be considered promising potential wound dressings.

Novel Curcumin-Encapsulated α-Tocopherol Nanoemulsion System and Its Potential Application for Wound Healing in Diabetic Animals

Objective

This project was aimed at formulating a novel nanoemulsion system and evaluating it for open incision wound healing in diabetic animals.

Methods

The nanoemulsions were characterized for droplet size and surface charge, drug content, antioxidant and antimicrobial profiling, and wound healing potential in diabetic animals. The skin samples excised were also analyzed for histology, mechanical strength, and vibrational and thermal analysis.

Results

The optimized nanoemulsion (CR-NE-II) exhibited droplet size of26.76 ± 0.9 nm with negative surface charge (−10.86 ± 1.06 mV), was homogenously dispersed with drug content of68.05 ± 1.2%, released almost82.95 ± 2.2%of the drug within first 2 h of experiment with synergistic antioxidant (95 ± 2.1%) and synergistic antimicrobial activity against selected bacterial strains in comparison to blank nanoemulsion, and promoted significantly fast percent reepithelization (96.47%). The histological, vibrational, thermal, and strength analysis of selected skin samples depicted a uniform and even distribution of collagen fibers which translated into significant increase in strength of skin samples in comparison to the control group.

Conclusions

The optimized nanoemulsion system significantly downregulated the oxidative stress, enhanced collagen deposition, and precluded bacterial contamination of wound, thus accelerating the skin tissue regeneration process.

Tachyplesin I Analogue Peptide as an Effective Antimicrobial Agent against Candida albicans-Staphylococcus aureus Poly-Biofilm Formation and Mixed Infection

Microbial biofilms are difficult to tackle in many infectious diseases. Candida albicans and Staphylococcus aureus are prevalent symbiotic strains in polymicrobial biofilms, which showed enhanced antimicrobial resistance and made identifying effective treatment techniques more difficult. The antibiofilm abilities of tachplesin I analogue peptide (TP11A) and tachplesin I were investigated quantitatively in this study. Both inhibited C. albicans monomicrobial, S. aureus monomicrobial, and C. albicans-S. aureus polymicrobial biofilms quite well. TP11A suppressed the biofilm- and virulence-related genes of C. albicans (hwp 1) and S. aureus (ica A, fnb B, agr A, hla, nor A, and sig B) in the mixed biofilm, according to quantitative reverse transcription polymerase chain reaction analysis. We created an injectable thermosensitive in situ PLEL@TP11A gel system by simply adding TP11A into poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PLEL). Using C. albicans-S. aureus mixed infected wound models of mice, the in vivo therapeutic effect of TP11A and PLEL@TP11A in polymicrobial infections was investigated. The findings revealed that TP11A and PLEL@TP11A could efficiently reduce bacterial and fungal burden in wound infections, as well as accelerated wound healing. Based on above findings, TP11A might be an effective antimicrobial against C. albicans-S. aureus poly-biofilm formation and mixed infection.

Polymer-Based Hydrogels Enriched with Essential Oils: A Promising Approach for the Treatment of Infected Wounds

Among the factors that delay the wound healing process in chronic wounds, bacterial infections are a common cause of acute wounds becoming chronic. Various therapeutic agents, such as antibiotics, metallic nanoparticles, and essential oils have been employed to treat infected wounds and also prevent the wounds from bacterial invasion. Essential oils are promising therapeutic agents with excellent wound healing, anti-inflammatory and antimicrobial activities, and good soothing effects. Some essential oils become chemically unstable when exposed to light, heat, oxygen, and moisture. The stability and biological activity of essential oil can be preserved via loading into hydrogels. The polymer-based hydrogels loaded with bioactive agents are regarded as ideal wound dressings with unique features, such as controlled and sustained drug release mechanisms, good antibacterial activity, non-toxicity, excellent cytocompatibility, good porosity, moderate water vapour transmission rate, etc. This review addresses the pre-clinical outcomes of hydrogels loaded with essential oils in the treatment of infected wounds.

An optimized mouse model of Staphylococcus aureus infected diabetic ulcers

OBJECTIVE

Diabetic foot infection (DFI) represents a major healthcare burden, for which treatment is challenging owing to the pathophysiological alterations intrinsic to diabetes and the alarming increase of antimicrobial resistance. Novel therapies targeting DFI are therefore a pressing research need for which proper models of disease are required.

RESULTS

Here, we present an optimized diabetic mouse model of methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds, that resemble key features of DFI, such as pathogen invasion through wound bed and surrounding tissue, necrosis, persistent inflammation and impaired wound healing. Thus, in a time-efficient manner and using simple techniques, this model represents a suitable approach for studying emerging therapies targeting DFI caused by MRSA.

Escherichia coli BarA-UvrY regulates the pks island and kills Staphylococci via the genotoxin colibactin during interspecies competition

Wound infections are often polymicrobial in nature, biofilm associated and therefore tolerant to antibiotic therapy, and associated with delayed healing. Escherichia coli and Staphylococcus aureus are among the most frequently cultured pathogens from wound infections. However, little is known about the frequency or consequence of E. coli and S. aureus polymicrobial interactions during wound infections. Here we show that E. coli kills Staphylococci, including S. aureus, both in vitro and in a mouse excisional wound model via the genotoxin, colibactin. Colibactin biosynthesis is encoded by the pks locus, which we identified in nearly 30% of human E. coli wound infection isolates. While it is not clear how colibactin is released from E. coli or how it penetrates target cells, we found that the colibactin intermediate N-myristoyl-D-Asn (NMDA) disrupts the S. aureus membrane. We also show that the BarA-UvrY two component system (TCS) senses the environment created during E. coli and S. aureus mixed species interaction, leading to upregulation of pks island genes. Further, we show that BarA-UvrY acts via the carbon storage global regulatory (Csr) system to control pks expression. Together, our data demonstrate the role of colibactin in interspecies competition and show that it is regulated by BarA-UvrY TCS during interspecies competition.

Wound infections are often polymicrobial in nature and are associated with poor disease prognoses. Escherichia coli and Staphylococcus aureus are among the top five most cultured pathogens from wound infections. However, little is known about the polymicrobial interactions between E. coli and S. aureus during wound infections. In this study, we show that E. coli kills S. aureus both in vitro and in a mouse excisional wound model via the genotoxin, colibactin. We also show that the BarA-UvrY two component system (TCS) regulates the pks island during this mixed species interaction, acting through the carbon storage global regulatory (Csr) system to control colibactin production. Together, our data demonstrate the role of colibactin in interspecies competition and show that it is regulated by BarA-UvrY TCS during interspecies competition.

Silver Nanoparticles and Its Mechanistic Insight for Chronic Wound Healing: Review on Recent Progress

Wounds are structural and functional disruptions of skin that occur because of trauma, surgery, acute illness, or chronic disease conditions. Chronic wounds are caused by a breakdown in the finely coordinated cascade of events that occurs during healing. Wound healing is a long process that split into at least three continuous and overlapping processes: an inflammatory response, a proliferative phase, and finally the tissue remodeling. Therefore, these processes are extensively studied to develop novel therapeutics in order to achieve maximum recovery with minimum scarring. Several growth hormones and cytokines secreted at the site of lesions tightly regulates the healing processes. The traditional approach for wound management has been represented by topical treatments. Metal nanoparticles (e.g., silver, gold and zinc) are increasingly being employed in dermatology due to their favorable effects on healing, as well as in treating and preventing secondary bacterial infections. In the current review, a brief introduction on traditional would healing approach is provided, followed by focus on the potential of wound dressing therapeutic techniques functionalized with Ag-NPs.

The Effect of Gracilaria Corticata and Scenedesmus Acuminates Extract Mixture on the Healing of Wounds Contaminated with Staphylococcus in the Rat Model

INTRODUCTION

Wound healing processes are dependent on the severity of the trauma, invasion of opportunistic microorganisms, and inflammatory, immunological, and metabolic responses. We tried to show the ability of algae to inhibit wound infection, which can lead to proper wound healing.

METHODS

Eighty rats were housed according to laboratory animal care protocols and divided into four groups at each operating time. Group I consisted of the non-treated animals. Group II was treated with 25% zinc oxide as a choice treatment. In the treated groups 3 and 4, an equal ratio of Gracilaria Corticata and Scenedesmus acuminate marine algae (mixed algae) was applied as 3% and 7% ointment pomade. Percentage of wound closure, number of bacteria in the wound surface, angiogenesis (Vascular endothelial growth factor; VEGF), the number of macrophages, collagen production level and transforming growth factor-beta (TGFβ), epithelialization, and fibrosis were evaluated.

RESULTS

Applying mixed algae extract 7% and zinc oxide 25% could result in a mild improvement in wound closure (df: 9, 48; F=5.97; p<0.0001). In addition, mixed algae 3%, mixed algae 7% and zinc oxide could reduce the rate of bacterial growth compared to non-treated animals (df: 3, 16; F=5.74; p=0.0007). However, these improvements do not seem to be clinically significant. Induction of angiogenesis, increase in macrophage infiltration rate, and expression of TGFβ are possible underlying mechanisms of mixed algae in accelerating wound healing process.

CONCLUSION

The result showed that the administration of 3% and 7% mixed algae could mildly accelerate the wound healing process in a rat model of pelleted skin wound. However, it seems that its effect is not clinically significant compared to non-treated and zinc oxide treated animals.

Formulation, In Vitro Characterization and Antibacterial Activity of Chitosan-Decorated Cream Containing Bacitracin for Topical Delivery

(1) Background: Bacitracin is a broad spectrum antibiotic that is used against various microorganisms. Chitosan is a natural polymer that has been widely investigated as an antimicrobial agent for preventing and treating infections owing to its intrinsic antimicrobial properties, as well as its ability to effectively deliver extrinsic antimicrobial compounds to infected areas. Topical drug delivery offers important benefits for improving the therapeutic effect and reducing systemic side effects of administered compounds/drugs. The topical use of chitosan-decorated bacitracin-loaded cream improves the permeation of the drug across the skin and enhances the drug bioavailability by prolonging the residence time of the drug when applied topically, as well as producing synergistic effects and reducing the side effects of the drug. Topical chitosan-decorated cream can be a promising approach to administer the drug more efficiently and enhance the efficacy of treatment in wound healing and antibacterial activity. (2) Methods: This study was conducted to prepare, assess and investigate the synergistic antibacterial activity of a chitosan-coated bacitracin cream. The results were compared to the antibacterial activity of simple bacitracin-loaded cream. The prepared cream was evaluated for various in vitro characteristics such as rheology, pH, viscosity, drug content and antibacterial activity studies. (3) Result: The formulations were found to be stable regarding color, liquefaction and phase separation at all accelerated conditions. It was observed that with time, substantial variations in the pH of the preparations were found. The introduction of chitosan results in controlled release of the drug from the formulations. The antibacterial activity of the formulated creams was assessed with the disc diffusion method against Staphylococcus aureus(ATCC),Escherichiacoli (STCC),Pseudomonas aeruginosa(ATCC) and Bacillus cereus(ATCC). The strains, E. coli, S. aureus, P. aeruginosa and B. cereus were susceptible to 50 µg chitosan-decorated bacitracin cream, showing inhibition zones of 10 ± 0.6, 34 ± 1.5, 31 ± 0.76 and 21 ± 2.02 mm, respectively. The zones of inhibition for simple bacitracin-loaded cream were significantly smaller than chitosan-decorated cream, at 2 ± 0.2, 28 ± 0.92, 15 ± 0.5 and 11 ± 1.25 mm (ANOVA; p < 0.05), respectively. (4) Conclusion: It was observed that the zones of inhibition of simple bacitracin-loaded cream were significantly smaller than those of chitosan-decorated bacitracin-loaded cream. Chitosan synergistically improves the antimicrobial activity of bacitracin. Hence, the developed formulation was effective and should be considered as a suitable candidate for topical management of skin infections and wound healing.

Antimicrobial Peptide-Loaded Gelatinase-Responsive Photothermal Nanogel for the Treatment of Staphylococcus aureus-Infected Wounds

As the most common pathogen of community and nosocomial infection, the resistance of Staphylococcus aureus (S. aureus) to traditional antibiotics is still increasing with years. Although the potent antibacterial activity of antimicrobial peptides (AMPs) has been widely confirmed, the unpredictable cytotoxicity remains the biggest obstacle to their clinical application. The development of a targeted drug delivery system for S. aureus is a practical strategy to ameliorate the inherent limitations of AMPs. In this work, we constructed an AMP release nanogel (cypate-GNPs@Cy3-AMP, CGCA) of S. aureus infection microenvironment using gelatinase nanoparticles (GNPs) for toxicity control and bacterial clearance. Gelatinase present in the infected site degrades GNPs, thus releasing Cy3-AMP in situ to destroy bacterial cells. Cypate modified on the surface of GNPs supports CGCA to generate localized heat under near-infrared (NIR) laser irradiation, which together with AMPs could cause irreversible physical damage to bacteria. In addition, the encapsulation from GNPs not only effectively limited the toxicity of AMPs but also significantly promoted cell proliferation and migration in vitro. In the mouse infection model, CGCA also exhibited excellent effects of bacterial clearance and wound healing, providing a potential direction for the correct use of AMPs.

Synergic dual phototherapy: Cationic imidazolyl photosensitizers and ciprofloxacin for eradication of in vitro and in vivo E. coli infections

The emergence of new microorganisms with resistance to current antimicrobials is one of the key issues of modern healthcare that must be urgently addressed with the development of new molecules and therapies. Photodynamic inactivation (PDI) in combination with antibiotics has been recently regarded as a promising wide-spectrum therapy for the treatment of localized topical infections. However, further studies are required regarding the selection of the best photosensitizer structures and protocol optimization, in order to maximize the efficiency of this synergic interaction. In this paper, we present results that demonstrate the influence of the structure of cationic imidazolyl-substituted photosensitizers and light on the enhancement of ciprofloxacin (CIP) activity, for the inactivation of Escherichia coli. Structure-activity studies have highlighted the tetra cationic imidazolyl porphyrin IP-H-Me⁴⁺ at sub-bactericide concentrations (4-16 nM) as the most promising photosensitizer for combination with sub-inhibitory CIP concentration (<0.25 mg/L). An optimized dual phototherapy protocol using this photosensitizer was translated to in vivo studies in mice wounds infected with E. coli. This synergic combination reduced the amount of photosensitizer and ciprofloxacin required for full E. coli inactivation and, in both in vitro and in vivo studies, the combination therapy was clearly superior to each monotherapy (PDI or ciprofloxacin alone). Overall, these findings highlight the potential of cationic imidazolyl porphyrins in boosting the activity of antibiotics and lowering the probability of resistance development, which is essential for a sustainable long-term treatment of infectious diseases.

Nanobiotechnology: Applications in Chronic Wound Healing

Wounds occur when skin integrity is broken and the skin is damaged. With progressive changes in the disease spectrum, the acute wounds caused by mechanical trauma have been become less common, while chronic wounds triggered with aging, diabetes and infection have become more frequent. Chronic wounds now affect more than 6 million people in the United States, amounting to 10 billion dollars in annual expenditure. However, the treatment of chronic wounds is associated with numerous challenges. Traditional remedies for chronic wounds include skin grafting, flap transplantation, negative-pressure wound therapy, and gauze dressing, all of which can cause tissue damage or activity limitations. Nanobiotechnology — which comprises a diverse array of technologies derived from engineering, chemistry, and biology — is now being applied in biomedical practice. Here, we review the design, application, and clinical trials for nanotechnology-based therapies for chronic wound healing, highlighting the clinical potential of nanobiotechnology in such treatments. By summarizing previous nanobiotechnology studies, we lay the foundation for future wound care via a nanotech-based multifunctional smart system.

Tiny tots for a big-league in wound repair: Tools for tissue regeneration by nanotechniques of today

Overall, chronic injuries place considerable burden on patients and health systems. The skin injuries are exposed to inflammatory bacteria and hinder the healing process. The skin being the biggest tissue of the whole body ensures protection against microbial invasion, dehydration, and against chemical, thermal, bright radiations and mechanical agents. When injured, the skin loses its defensive purpose and the attack of bacterial types arises with the loss of protein, water, and electrolytes. Improved wound closure therapy helps to restore normal skin function by managing wounds with the help of a suitable skin replacement. According to the type of wound and its healing ability, an appropriate skin replacement system must be identified. Nanofibrous layers because of their permeable structure, their large superficial reach and their similarity with the local extracellular network serve as cutaneous substitution for dealing with deep and superficial injuries. By a diminished microbial load without infestation, scab formation and infiltration of defense cells in the initial phase, acute injuries are usually characterized. Here recovery is related with epithelialization, angiogenesis and relocation of fibroblasts. The wound becomes obstinate when microbial biofilms are developed while the immune system does not manage to eliminate the infection. Increased inflammatory process, lower deep tissue oxygenation, fibrin cuffs, fibroblastic senescence, altered angiogenesis, stalled re-epithelialization and chronic infection have been visualized. Conventional wound mending treatments for the most part falling flat to supply a great clinical result, either basically like wound epithelialization and regulation of fluid loss or practically like histological highlights that decide versatility, strength, affectability, etc. Conventional wound therapies commonly fail to offer a better medical output, like wound epithelialization and regulation of fluid reduction or physiologically like cellular features that determine durability, sensitivity, elasticity, etc. Nanotechnology may be a dependable investigation space for wound-healing treatments through their versatile physicochemical properties. Advancing nano platforms with novel solutions for curing chronicdiabetic wounds are discussed in detail that can guide further research in this sector.

Calcium alginate/PNIPAAm hydrogel with body temperature response and great biocompatibility: Application as burn wound dressing

Deep burns often do not heal easily, because the dermis of the skin is severely damaged, leading to severe inflammation and bacterial infection. Therefore, it is of great clinical significance to develop a dressing that promotes the healing process of deep burn wound. In this study, we used N-isopropyl acrylamide, sodium alginate and calcium chloride as the main materials, a series of calcium alginate/ poly (N-isopropyl acrylamide)(NIPAAm) hydrogel (CAPH) with different component ratios were synthesized. Its swelling properties, temperature response properties, rheological properties, biocompatibility properties, and in vitro drug release properties were investigated. Based on the above conditions, the CAPH(sodium alginate:NIPAAm = 2:15) with the best comprehensive performance was selected, which has a good biocompatibility. In addition, 0.02 % (w/v) mupirocin was loaded in CAPH. The temperature-responsive property of PNIPAAm in CAPH at 34 °C not only allowed the CAPH to rapidly release the drug under to prevent infection, but also to assist in wound contraction. Application of CAPH to localized wounds of deep second-degree burns in mice showed a faster healing rate and tissue regeneration. At the same time, collagen recovery was enhanced, collagen bundles were arranged in an orderly manner, and the scarring was not obvious after 16 days. Therefore, this research prepared a new safe and effective biomaterial.

A cellulose nanofibril-reinforced hydrogel with robust mechanical, self-healing, pH-responsive and antibacterial characteristics for wound dressing applications

Background

Bacterial infection in wounds has become a major threat to human life and health. With the growth use of synthetic antibiotics and the elevated evolution of drug resistant bacteria in human body cells requires the development of novel wound curing strategies. Herein, a novel pH-responsive hydrogel (RPC/PB) was fabricated using poly(vinyl alcohol)-borax (PB) and natural antibiotic resveratrol grafted cellulose nanofibrils (RPC) for bacterial-infected wound management.

Results

In this hydrogel matrix, RPC conjugate was interpenetrated in the PB network to form a semi-interpenetrating network that exhibited robust mechanical properties (fracture strength of 149.6 kPa), high self-healing efficiency (> 90%), and excellent adhesion performance (tissue shear stress of 54.2 kPa). Interestingly, the induced RPC/PB hydrogel showed pH-responsive drug release behavior, the cumulative release amount of resveratrol in pH 5.4 was 2.33 times than that of pH 7.4, which was adapted well to the acidic wound microenvironment. Additionally, this RPC/PB hydrogel exhibited excellent biocompatibility and antioxidant effect. Moreover, in vitro and in vivo results revealed that such RPC/PB hydrogel had excellent antibacterial, skin tissue regeneration and wound closure capabilities.

Conclusion

Therefore, the generated RPC/PB hydrogel could be an excellent wound dressing for bacteria-infected wound healing.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01523-5.

Antimicrobial effects of bacterial binding to a dialkylcarbamoyl chloride-coated wound dressing: an in vitro study

OBJECTIVE

Wound dressings that inactivate or sequestrate microorganisms, such as those with a hydrophobic, bacteria-binding dialkylcarbamoyl chloride (DACC) surface, can reduce the risk of clinical infections. This 'passive' bioburden control, avoiding bacterial cell wall disruption with associated release of bacterial endotoxins aggravating inflammation, is advantageous in hard-to-heal wounds. Hence, the full scope of DACC dressings, including the potential impact of higher inoculum densities, increased protein load and different pH on antibacterial activity, needs to be evaluated.

METHOD

The Japanese Industrial Standard (JIS) L 1902 challenge test was used to evaluate the antimicrobial activity of the DACC-coated dressing against several World Health Organization (WHO)-prioritised wound pathogens (e.g., meticillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, microorganisms with extended-spectrum beta-lactamases and Acinetobacter baumannii), the effect of repeated bacterial challenge in an adverse wound environment, and antimicrobial performance at wound-related pH.

RESULTS

High antibacterial activity of the DACC-coated dressing against the WHO-prioritised bacteria strains by its irreversible binding and inhibition of growth of bound bacteria was confirmed using JIS L 1902. At increased inoculation densities, compared to standard conditions, the DACC-coated dressing still achieved strong-to-significant antibacterial effects. Augmenting the media protein content also affected antibacterial performance; a 0.5-1 log reduction in antibacterial activity was observed upon addition of 10% fetal calf serum. The pH did not influence antibacterial performance. The DACC-coated dressing also sustained antibacterial activity over subsequent reinfection steps.

CONCLUSION

It can be assumed that the DACC-coated dressing exerts beneficial effects in controlling the wound bioburden, reducing the overall demand placed on antibiotics, without using antimicrobial substances.

Larval Therapy for Treatment of Chronic Wounds Colonized by Multi-resistant Pathogens in a Pediatric Patient: A Case Study

BACKGROUND

Chronic wounds are susceptible to colonization with gram-positive and gram-negative bacteria that may be resistant to antimicrobial dressings and systemic antibiotics. In January 2004, the US Food and Drugs Administration approved use of medicinal larvae for use in humans and animals for resistant organisms. Despite use in adults, there is a paucity of evidence evaluating its efficacy and safety in the pediatric population.

CASE

T was a 5-year-old boy with several chronic wounds infected with multidrug-resistant Pseudomonas aeruginosa. The wounds were originally treated with chemical debridement, dressings containing ionic silver, negative-pressure wound therapy (NPWT), and antibiotics without success. Consequently, a multidisciplinary team implemented maggot debridement therapy (MDT).

CONCLUSIONS

After MDT, one wound completely epithelialized and the other wounds achieved a reduction in size with 70% epithelization. Therapy also led to a reduction in wound odor, exudate, and pain. The other wounds were closed after additional management with dressing containing nanocrystalline silver and NPWT.

Poly (vinyl alcohol) copolymerized with xanthan gum/hypromellose/sodium carboxymethyl cellulose dermal dressings functionalized with biogenic nanostructured materials for antibacterial and wound healing application

Effective treatment of infected wounds requires a comprehensive wound dressing with a combination of antibacterial, antioxidative, and anti-inflammatory effects. Biodegradable wound dressings incorporating nanostructured material were developed using polyvinyl alcohol with xanthan gum, hypromellose, or sodium carboxymethyl cellulose and extensively evaluated for antibacterial and wound healing efficacy. Synthesized silver nanoparticles and wound dressings displayed λ_max at 420 nm with zeta potential ≈ - 35 mV. Significant growth inhibition with >99 % reduction in CFU/ml (p < 0.05) against important wound pathogens including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans were observed. Within 1 h of treatment, hypromellose nanocomposite demonstrated excellent bactericidal effects with a 99.9 % of reduction in growth. In addition, wound dressings demonstrated inhibitory activities against free radical scavengers. Wound dressings demonstrated a significant reduction in the inflammatory response in RAW 264.7 macrophages (p < 0.001). Ex-vivo diffusion demonstrated zero-order release and steady-state flux between 0.1571-0.2295 μg/ml/cm²h with 0.124-0.144 permeability coefficient after 10 h. Usage in animals further confirmed that the hypromellose nanocomposite accelerated the wound healing process with biocompatibility. The results suggested that hybrid biodegradable dressings can be effectively applied to treat infected wounds and attenuate inflammatory responses.

Development of an antibiotics delivery system for topical treatment of the neglected tropical disease Buruli ulcer

Skin infection by Mycobacterium ulcerans causes Buruli ulcer (BU) disease, a serious condition that significantly impact patient' health and quality of life and can be very difficult to treat. Treatment of BU is based on daily systemic administration of antibiotics for at least 8 weeks and presents drawbacks associated with the mode and duration of drug administration and potential side effects. Thus, new therapeutic strategies are needed to improve the efficacy and modality of BU therapeutics, resulting in a more convenient and safer antibiotic regimen. Hence, we developed a dual delivery system based on poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) microparticles and a gellan gum (GG) hydrogel for delivery of rifampicin (RIF) and streptomycin (STR), two antibiotics used for BU treatment. RIF was successfully loaded into PHBV microparticles, with an encapsulation efficiency of 43%, that also revealed a mean size of 10 µm, spherical form and rough topography. These microparticles were further embedded in a GG hydrogel containing STR. The resultant hydrogel showed a porous microstructure that conferred a high water retention capability (superior to 2000%) and a controlled release of both antibiotics. Also, biological studies revealed antibacterial activity against M. ulcerans, and a good cytocompatibility in a fibroblast cell line. Thus, the proposed drug delivery system can constitute a potential topical approach for treatment of skin ulcers caused by BU disease.

Investigation of wound healing potential of photo-active curcumin-ZnO-nanoconjugates in excisional wound model

Wound healing, being a dynamic process consisting of hemostasis, inflammation, proliferation, and remodeling, involves the complicated interplay of various growth mediators and the cells associated repair system. Current wound healing therapies usually fail to completely regain skin integrity and functionality. Traditionally, curcumin is considered a potent natural wound healing agent as it possesses antibacterial, antioxidant, and anti-inflammatory properties. It is also known that zinc oxide (ZnO) nanoparticles (NPs) have photocatalytic properties, including the generation of reactive oxygen species. ZnO nanoaprticles are also Food and Drug Administration (FDA) approved as safe substances. While ZnO oxide requires illumination with ultraviolet light to become photocatalytically active, dye-sensitized ZnO can be activated by illumination with visible light. In the present study, we explored the wound healing potential of ZnO nanoparticles sensitized with curcumin (Cu+ZnO Nps) and illuminated with visible (blue) light generated by an array of high power LEDs. We studied the antibacterial effect of our conjugates by percentage reduction in bacterial growth and biofilm formation. The wound healing potential was analyzed by percentage wound contraction, biochemical parameters, and histopathological analysis of the wounded site. Additionally, angiogenesis and wound associated cytokines was evaluated by immunohistochemistry of CD31 and gene expression analysis of IL-1β, TNF-α, and MMP-9 after 16 days of post-wound treatment, respectively. Our study suggests that the therapeutic effect of Cu+ZnO NPs with LED illumination increases its wound healing potential by producing an antibacterial and anti-inflammatory effect. Moreover, the treatment strategy of using a nano formulation in combination with LED illumination further increases its efficacy. It was concluded that the anti-inflammatory and bactericidal effects of the LED illuminated Cu+ZnO Np showed accelerated wound healing with increased wound contraction, collagen deposition, angiogenesis, and re-epithelialization.

Aqueous decomposition behavior of solid peroxides: Effect of pH and buffer composition on oxygen and hydrogen peroxide formation

The ability of solid peroxides to provide sustained release of both oxygen and hydrogen peroxide makes them potentially suitable for oxygen release or antibacterial applications. Most recent reports using solid peroxides to augment oxygen levels do so by compounding solid peroxide powders in polymers to retard the aqueous decomposition. Compounds with peroxidase activity may be added to reduce hydrogen peroxide toxicity. Peroxides are rarely pure and are mixed with oxide and themselves decompose to form hydroxides in water. Therefore, even if buffering strategies are used, locally the pH at the surface of aqueously immersed peroxide particles is inevitably alkaline. Since pH affects the decomposition of peroxides and hydrogen peroxide stability, this study compared for the first-time the aqueous decomposition products of hydrogen and inorganic peroxides that are in use or have been used for medical applications of have been evaluated preclinically; calcium peroxide (CaO₂), magnesium peroxide (MgO₂), zinc peroxide (ZnO₂), sodium percarbonate (Na₂CO₃.1.5H₂O₂) and hydrogen peroxide (H₂O₂). Since plasma can be approximated to be carbonate buffered phosphate solution, we maintained pH using carbonate and phosphate buffers and compared results with citrate buffers. For a given peroxide compound, we identified not only a strong effect of pH but also of buffer composition on the extent to which oxygen and hydrogen peroxide formation occurred. The influence of buffer composition was not previously appreciated, thereby establishing in vitro parameters for better design of intentional release of specific decomposition species. STATEMENT OF SIGNIFICANCE: This paper compares for the first time the aqueous decomposition products oxygen and hydrogen peroxide of solid peroxy compounds of metal cations, (calcium, magnesium, sodium and zinc) across a pH range that could feasibly be found in the body, (pH 5,7, 9) either physiologically or pathologically. We find that in addition to pH, buffer composition is also a critically important factor, making translation from in vitro models challenging. Cytotoxicity was related to hydrogen peroxide release, alkalinity and in the case of zinc peroxide to the cation itself. In vitro and preclinical studies generally report release data from polymer-peroxide composites and rarely compare peroxides with one another. Together our data provide guidance for oxygen and ROS delivery from these inorganic materials.

ELECTROSPUN SODIUM ALGINATE/POLY(ETHYLENE OXIDE) NANOFIBERS FOR WOUND HEALING APPLICATIONS: CHALLENGES AND FUTURE DIRECTIONS

Alginate is an interesting natural biopolymer to be considered for biomedical applications due to its advantages and good biological properties. These biological properties make electrospun alginate nanofibers suitable for various uses in the biomedical field, such as wound healing dressings, drug delivery systems, or both. Unfortunately, the fabrication of alginate nanofibers by electrospinning is very challenging because of the high viscosity of the solution, high surface tension and rigidity in water due to hydrogen bonding, and also their diaxial linkages. This review presents an overview of the factors affecting the electrospinning process of sodium alginate/poly(ethylene oxide) (SA/PEO), the application of SA/PEO in drug delivery systems for wound healing applications, and the degradation and swelling properties of SA/PEO. The challenges and future directions of SA/PEO in the medical field are also discussed.

Solvent Casting and UV Photocuring for Easy and Safe Fabrication of Nanocomposite Film Dressings

The aim of this work was to optimize and characterize nanocomposite films based on gellan gum methacrylate (GG-MA) and silver nanoparticles (AgNPs) for application in the field of wound dressing. The films were produced using the solvent casting technique coupled with a photocuring process. The UV irradiation of GG-MA solutions containing glycerol as a plasticizer and different amounts of silver nitrate resulted in the concurrent crosslinking of the photocurable polymer and a reduction of Ag ions with consequent in situ generation of AgNPs. In the first part of the work, the composition of the films was optimized, varying the concentration of the different components, the GG-MA/glycerol and GG-MA/silver nitrate weight ratios as well as the volume of the film-forming mixture. Rheological analyses were performed on the starting solutions, whereas the obtained films were characterized for their mechanical properties. Colorimetric analyses and swelling studies were also performed in order to determine the AgNPs release and the water uptake capacity of the films. Finally, microbiological tests were carried out to evaluate the antimicrobial efficacy of the optimized films, in order to demonstrate their possible application as dressings for the treatment of infected hard-to-heal wounds, which is a demanding task for public healthcare.

Implications of endotoxins in wound healing: a narrative review

Bacterial toxins are thought to play a role in delayed wound healing in critically colonised and infected wounds. Endotoxins are released from Gram-negative bacteria when they are lysed by host phagocytic cells during an immune response, or by antimicrobial agents, potentially leading to a detrimental effect on the host tissues. Endotoxins can affect all aspects of the wound healing process, leading to delayed healing and contributing to wound chronicity. Release of endotoxins by bacteria can also have serious systemic effects (for example, septic shock) that can lead to high levels of patient mortality. This review summarises the role and implications on wound healing of bacterial endotoxins, describing the impact of endotoxins on the various phases of the wound healing response. There is a paucity of in vivo/clinical evidence linking endotoxins attributed to a wound (via antibiotic treatment) or their release from infecting bacteria with parameters of delayed wound healing. Future work should investigate if this link is apparent and determine the mechanism(s) by which such detrimental effects occur, offering an opportunity to identify possible treatment pathways. This paper describes the phenomenon of antimicrobial-induced endotoxin release and summarises the use of wound dressings to reduce wound bioburden without inducing microbial death and subsequent release of endotoxins, thus limiting their detrimental effects.

Effective Treatment of Skin Wounds Co-Infected with Multidrug-Resistant Bacteria with a Novel Nanoemulsion

Wound infections with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) are particularly difficult to treat and present a great challenge to clinicians. Nanoemulsions (NE) are novel oil-in-water emulsions formulated from soybean oil, water, solvent, and surfactants such as benzalkonium chloride (BZK). An optimal ratio of those components produces nanometer-sized particles with the positive-charged surfactant at their oil-water interface. We sought to investigate antimicrobial NE as a novel treatment to address wounds co-infected by MRSA and VRE. Swine split-thickness skin wounds were first infected with MRSA and/or VRE, then treated with the nanoemulsion formulation (X-1735) or placebo controls. Bacterial viability after treatment were determined by nutrient agar plates for total, MRSA-specific, and VRE-specific loads. In addition, inflammation indexes were scored by histopathology. When VRE infected wounds were treated with X-1735, they contained 103 lower VRE CFU counts across a 2-week period compared with placebo. Once co-infected MRSA and VRE split-thickness wounds were successfully established, topical treatment of co-infected wounds with X-1735 resulted in a reduction of bacteria by 2 to 3 logs (compared with placebo) at 3- and 14-day postinfection time points. Importantly, X-1735 was effective in significantly alleviating multilevel inflammation in the treated wounds. X-1735 is a new antimicrobial that is safe to apply to open wounds and effectively kills MRSA and VRE. It appears to also reduce inflammation in these co-infected wounds. The data suggest that this approach offers promise as an antimicrobial for open wounds with MRSA and VRE co-infection. IMPORTANCE Infections, specifically polymicrobial, can cause serious consequences when it comes to wound treatment. Prolonged treatment with antibiotics can lead to an increased risk of bacterial resistance; co-infections can complicate treatment options even further. Our research proposes a novel nanoemulsion treatment for two of the most common antibiotic resistant bacteria: methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant enterococci (VRE). This optimized topical treatment formulation not only significantly reduces inflammation and infection in MRSA or VRE infected wounds, but also in MRSA and VRE co-infected wounds as well. The work aims to provide an alternative treatment approach for multidrug-resistant organisms and decrease dependence on systemic treatments.

Transperineal pelvic drainage combined with lateral position to promote perineal wound healing after abdominoperineal resection: A prospective cohort trial

BACKGROUND

For the rectal cancer <5 cm from anal margin, extralevator abdominoperineal resection (eAPR) has been accepted widely by surgeons. However, the rate of perineal infection following up eAPR is approximately 70%. We did the study with the aim of evaluating the effect and safety of transperineal pelvic drainage combined with lateral position (TPDLP) on perineal wound in patients undergoing eAPR.

METHODS

Patients were randomly assigned to N-TPDLP group (standard arm) or TPDLP group (intervention arm). In the standard arm, surgery was completed after abdominal drainage tube was placed in pelvic. Comparatively, an additional transperineal wound drainage tube was applied in the experimental arm. Postoperatively, patients of both 2 groups were informed not to sit to reduce perineal compression until the perineal wound healed. But lateral position was demanded in the intervention arm. The primary endpoint was the rate of uncomplicated perineal wound healing defined as a Southampton wound score of <2 at 30 days postoperatively. Patients were followed for 6 months.

RESULTS

In total, 60 patients were randomly assigned to standard arm (n = 31) and intervention arm (n = 29). The mean perineal wound healing time was 34.2 (standard deviation [SD] 10.9) days in TPDLP arm, which significantly differ from 56.4 (SD 34.1) in N-TPDLP arm (P = .001). At 30 days postoperatively, 3 (10%) of 29 patients undergoing TPDLP were classified into grade 4 according to Southampton wound score, however, 16 (52%) of 31 patients were classified into grade 4 in control arm, and significantly difference was observed between randomization groups (P = .001). What's more, perineal wound pain was assessed at 30 days postoperatively, and it is discovered that the pain degree of patients in control arm was significantly more severe than the interventive arm (P = .015).

CONCLUSION

In the present study, we found that TPDLP generated a favorable prognosis for perineal wounds with acceptable side-effects.

Progress in hydrogels for skin wound repair

As the first defensive line between the human body and the outside world, the skin is vulnerable to damage from the external environment. Skin wounds can be divided into acute wounds (mechanical injuries, chemical injuries and surgical wounds, etc.) and chronic wounds (burns, infections, diabetes, etc.). In order to manage skin wound, a variety of wound dressings have been developed, including gauze, films, foams, nanofibers, hydrocolloids and hydrogels. Recently, hydrogels have received much attention because of their natural extracellular matrix (ECM)-mimik structure, tunable mechanical properties, and facile bioactive substance delivery capability. They show great potential application in skin wound repair. This paper first introduces the anatomy and function of the skin, the process of wound healing and conventional wound dressings, and then introduces the composition and construction methods of hydrogels. Next, this paper introduces the necessary properties of hydrogels in skin wound repair and the latest research progress of hydrogel dressings for skin wound repair. Finally, the future development goals of hydrogel materials in the field of wound healing are proposed. This article is protected by copyright. All rights reserved.

Bee-Derived Products: Chemical Composition and Applications in Skin Tissue Engineering

Skin tissue regeneration is one of the population's most common problems, and the complications that may appear in the healing process can have detrimental consequences. An alternative to conventional treatments could be represented by sustainable materials based on natural products, such as honey and its derivates (propolis, royal jelly, bee pollen, beeswax, and bee venom). They exhibit significant inhibitory activities against bacteria and have great potential in dermal tissue regeneration. Research in the pharmaceutical field demonstrates that conventional medication combined with bee products can deliver better results. The advantages include minimizing side effects and maintaining the same effectiveness by using low concentrations of antibiotic, anti-inflammatory, or chemotherapy drugs. Several studies suggested that bee products can replace the antimicrobial activity and efficiency of antibiotics, but further investigation is needed to establish a topical mixture's potential, including honey, royal jelly, and propolis. Bee products seem to complete each other's deficiencies, and their mixture may have a better impact on the wound healing process. The topic addressed in this paper highlights the usefulness of honey, propolis, royal jelly, bee pollen, beeswax, and bee venom in the re-epithelization process and against most common bacterial infections.

Nanomaterials-based drug delivery approaches for wound healing

Abstract:

Wound healing is a complex and dynamic process that requires intricate synchronization between multiple cell types within appropriate extracellular microenvironment. Wound healing process involves four overlapping phases in a precisely regulated manner, consisting of hemostasis, inflammation, proliferation, and maturation. For an effective wound healing all four phases must follow in a sequential pattern within a time frame. Several factors might interfere with one or more of these phases in healing process, thus causing improper or impaired wound healing resulting in non-healing chronic wounds. The complications associated with chronic non-healing wounds, along with the limitations of existing wound therapies, have led to the development and emergence of novel and innovative therapeutic interventions. Nanotechnology presents unique and alternative approaches to accelerate the healing of chronic wounds by the interaction of nanomaterials during different phases of wound healing. This review focuses on recent innovative nanotechnology-based strategies for wound healing and tissue regeneration based on nanomaterials, including nanoparticles, nanocomposites and scaffolds. The efficacy of the intrinsic therapeutic potential of nanomaterials (including silver, gold, zinc oxide, copper, cerium oxide, etc.) and the ability of nanomaterials as carriers (liposomes, hydrogels, polymeric nanomaterials, nanofibers) as therapeutic agents associated with wound-healing applications have also been addressed. The significance of these nanomaterial-based therapeutic interventions for wound healing needs to be highlighted to engage researchers and clinicians towards this new and exciting area of bio-nanoscience. We believe that these recent developments will offer researchers an updated source on the use of nanomaterials as an advanced approach to improve wound healing.

New dynamic microreactor system to mimic biofilm formation and test anti-biofilm activity of nanoparticles

Microbial biofilms are composed of surface-adhered microorganisms enclosed in extracellular polymeric substances. The biofilm lifestyle is the intrinsic drug resistance imparted to bacterial cells protected by the matrix. So far, conventional drug susceptibility tests for biofilm are reagent and time-consuming, and most of them are in static conditions. Rapid and easy-to-use methods for biofilm formation and antibiotic activity testing need to be developed to accelerate the discovery of new antibiofilm strategies. Herein, a Lab-On-Chip (LOC) device is presented that provides optimal microenvironmental conditions closely mimicking real-life clinical biofilm status. This new device allows homogeneous attachment and immobilization of Pseudomonas aeruginosa PA01-EGFP cells, and the biofilms grown can be monitored by fluorescence microscopy. P. aeruginosa is an opportunistic pathogen known as a model for drug screening biofilm studies. The influence of flow rates on biofilms growth was analyzed by flow simulations using COMSOL® 5.2. Significant cell adhesion to the substrate and biofilm formation inside the microchannels were observed at higher flow rates > 100 µL/h. After biofilm formation, the effectiveness of silver nanoparticles (SNP), chitosan nanoparticles (CNP), and a complex of chitosan-coated silver nanoparticles (CSNP) to eradicate the biofilm under a continuous flow was explored. The most significant loss of biofilm was seen with CSNP with a 65.5% decrease in average live/dead cell signal in biofilm compared to the negative controls. Our results demonstrate that this system is a user-friendly tool for antibiofilm drug screening that could be simply applied in clinical laboratories.Key Points• A continuous-flow microreactor that mimics real-life clinical biofilm infections was developed.• The antibiofilm activity of three nano drugs was evaluated in dynamic conditions.• The highest biofilm reduction was observed with chitosan-silver nanoparticles.

Significant in-Vitro and in-Vivo Antimicrobial and Antibiofilm Activity of Colloidal Silver Nanoparticles (cAgNPs) in Chronic Diabetic Foot Ulcers

Infection is a foremost challenge in the cases of wound care, especially in cases of chronic wounds. The present study was conducted to determine the antimicrobial and antibiofilm activity of the colloidal silver nanoparticles (cAgNPs) on Gram positive organisms and to evaluate the in-vivo response of cAgNPs on patients of chronic diabetic foot ulcers (DFUs). cAgNPs were tested against selected Gram-positive organisms like methicillin-sensitive and resistant Staphylococcus aureus (MSSA, MRSA), Enterococcus faecalis and vancomycin resistant enterococci (VRE) using microbroth dilution assay to estimate minimum inhibitory/bactericidal concentration (MIC/MBC). Biofilm inhibition capacity and time kill assay was performed. Further, the in-vivo response of topical application of cAgNPs was evaluated on patients of DFUs. The susceptibility testing demonstrated the MIC and MBC values of the cAgNPs ranging from 0.5μg/ml to 1.0 μg/ml and 1.0 μg/ml to 8 μg/ml against the tested organisms respectively. The cAgNPs showed inhibition of biofilm formation in the low, medium and high biofilm producers by 91%, 83% and 75% respectively at the highest concentration (52ppm). The time kill kinetics showed significant reduction in the number of viable cells (p < 0.0001). Significant reduction in microbial load (p = 0.0062) and in the number of moderate to strong biofilm producing organisms (p = 0.0069) after treatment with cAgNPs was seen. cAgNPs exhibited significant in-vitro bactericidal and bacteriostatic activity against MRSA, MSSA and VRE respectively along with anti-biofilm activity. Additionally, cAgNPs showed significant reduction in microbial load of the chronic DFUs.

Treatment of Wound Infections in a Mouse Model Using Zn2+-Releasing Phage Bound to Gold Nanorods

Infections caused by drug-resistant bacteria, particularly Gram-negative organisms, are increasingly difficult to treat using antibiotics. A potential alternative is "phage therapy", in which phages infect and lyse the bacterial host. However, phage therapy poses serious drawbacks and safety concerns, such as the risk of genetic transduction of antibiotic resistance genes, inconsistent pharmacokinetics, and unknown evolutionary potential. In contrast, metallic nanoparticles possess precise, tunable properties, including efficient conversion of electronic excitation into heat. In this work, we demonstrate that engineered phage-nanomaterial conjugates that target the Gram-negative pathogen Pseudomonas aeruginosa are highly effective as a treatment of infected wounds in mice. Photothermal heating, performed as a single treatment (15 min) or as two treatments on consecutive days, rapidly reduced the bacterial load and released Zn²⁺ to promote wound healing. The phage-nanomaterial treatment was significantly more effective than systemic standard-of-care antibiotics, with a >10× greater reduction in bacterial load and ∼3× faster healing as measured by wound size reduction when compared to fluoroquinolone treatment. Notably, the phage-nanomaterial was also effective against a P. aeruginosa strain resistant to polymyxins, a last-line antibiotic therapy. Unlike these antibiotics, the phage-nanomaterial showed no detectable toxicity or systemic effects in mice, consistent with the short duration and localized nature of phage-nanomaterial treatment. Our results demonstrate that phage therapy controlled by inorganic nanomaterials can be a safe and effective antimicrobial strategy in vivo.

Benefit of Silver and Gold Nanoparticles in Wound Healing Process after Endometrial Cancer Protocol

It is intractable to manage the vast majority of wounds in a classical surgical manner, however if silver, likewise gold and its representative nanoparticles, can lead to the amelioration of the wound healing process after extensive procedures, they should be employed in the current gynecological practice as promptly as possible. Most likely due to its antimicrobial properties, silver is usually applied as an additional component in the wound healing process. In wound management, we obtained various aspects that can lead to impaired wound healing; the crucial aspect for the wound milieu is to prevent the offending agents from occurring. The greatest barrier to healing is represented by the bacterial biofilm, which can occur naturally or in other ways. Biofilm bacteria can produce extracellular polymers, which can then resist concentrated anti-bacterial treatment. The published literature on the use of silver nanoparticles' utilization in wound healing becomes slightly heterogenous and requires us in difficult moments to set up proper treatment guidelines.

Polymeric Nanoparticles-Loaded Hydrogels for Biomedical Applications: A Systematic Review on In Vivo Findings

Clinically available medications face several hurdles that limit their therapeutic activity, including restricted access to the target tissues due to biological barriers, low bioavailability, and poor pharmacokinetic properties. Drug delivery systems (DDS), such as nanoparticles (NPs) and hydrogels, have been widely employed to address these issues. Furthermore, the DDS improves drugs’ therapeutic efficacy while reducing undesired side effects caused by the unspecific distribution over the different tissues. The integration of NPs into hydrogels has emerged to improve their performance when compared with each DDS individually. The combination of both DDS enhances the ability to deliver drugs in a localized and targeted manner, paired with a controlled and sustained drug release, resulting in increased drug therapeutic effectiveness. With the incorporation of the NPs into hydrogels, it is possible to apply the DDS locally and then provide a sustained release of the NPs in the site of action, allowing the drug uptake in the required location. Additionally, most of the materials used to produce the hydrogels and NPs present low toxicity. This article provides a systematic review of the polymeric NPs-loaded hydrogels developed for various biomedical applications, focusing on studies that present in vivo data.

Inhibition of Collagenase Q1 of Bacillus cereus as a Novel Antivirulence Strategy for the Treatment of Skin-Wound Infections

Despite the progress in surgical techniques and antibiotic prophylaxis, opportunistic wound infections with Bacillus cereus remain a public health problem. Secreted toxins are one of the main factors contributing to B. cereus pathogenicity. A promising strategy to treat such infections is to target these toxins and not the bacteria. Although the exoenzymes produced by B. cereus are thoroughly investigated, little is known about the role of B. cereus collagenases in wound infections. In this report, the collagenolytic activity of secreted collagenases (Col) is characterized in the B. cereus culture supernatant (csn) and its isolated recombinantly produced ColQ1 is characterized. The data reveals that ColQ1 causes damage on dermal collagen (COL). This results in gaps in the tissue, which might facilitate the spread of bacteria. The importance of B. cereus collagenases is also demonstrated in disease promotion using two inhibitors. Compound 2 shows high efficacy in peptidolytic, gelatinolytic, and COL degradation assays. It also preserves the fibrillar COLs in skin tissue challenged with ColQ1, as well as the viability of skin cells treated with B. cereus csn. A Galleria mellonella model highlights the significance of collagenase inhibition in vivo.

Engineered Nanotechnology: An Effective Therapeutic Platform for the Chronic Cutaneous Wound

The healing of chronic wound infections, especially cutaneous wounds, involves a complex cascade of events demanding mutual interaction between immunity and other natural host processes. Wound infections are caused by the consortia of microbial species that keep on proliferating and produce various types of virulence factors that cause the development of chronic infections. The mono- or polymicrobial nature of surface wound infections is best characterized by its ability to form biofilm that renders antimicrobial resistance to commonly administered drugs due to poor biofilm matrix permeability. With an increasing incidence of chronic wound biofilm infections, there is an urgent need for non-conventional antimicrobial approaches, such as developing nanomaterials that have intrinsic antimicrobial-antibiofilm properties modulating the biochemical or biophysical parameters in the wound microenvironment in order to cause disruption and removal of biofilms, such as designing nanomaterials as efficient drug-delivery vehicles carrying antibiotics, bioactive compounds, growth factor antioxidants or stem cells reaching the infection sites and having a distinct mechanism of action in comparison to antibiotics-functionalized nanoparticles (NPs) for better incursion through the biofilm matrix. NPs are thought to act by modulating the microbial colonization and biofilm formation in wounds due to their differential particle size, shape, surface charge and composition through alterations in bacterial cell membrane composition, as well as their conductivity, loss of respiratory activity, generation of reactive oxygen species (ROS), nitrosation of cysteines of proteins, lipid peroxidation, DNA unwinding and modulation of metabolic pathways. For the treatment of chronic wounds, extensive research is ongoing to explore a variety of nanoplatforms, including metallic and nonmetallic NPs, nanofibers and self-accumulating nanocarriers. As the use of the magnetic nanoparticle (MNP)-entrenched pre-designed hydrogel sheet (MPS) is found to enhance wound healing, the bio-nanocomposites consisting of bacterial cellulose and magnetic nanoparticles (magnetite) are now successfully used for the healing of chronic wounds. With the objective of precise targeting, some kinds of "intelligent" nanoparticles are constructed to react according to the required environment, which are later incorporated in the dressings, so that the wound can be treated with nano-impregnated dressing material in situ. For the effective healing of skin wounds, high-expressing, transiently modified stem cells, controlled by nano 3D architectures, have been developed to encourage angiogenesis and tissue regeneration. In order to overcome the challenge of time and dose constraints during drug administration, the approach of combinatorial nano therapy is adopted, whereby AI will help to exploit the full potential of nanomedicine to treat chronic wounds.

Polysaccharide-based electroconductive hydrogels: Structure, properties and biomedical applications

Architecting an appropriate platform for biomedical applications requires setting a balance between simplicity and complexity. Polysaccharides (PSAs) play essential roles in our life in food resources, structural materials, and energy storage capacitors. Moreover, the diversity and abundance of PSAs have made them an indispensable part of food ingredients and cosmetics. PSA-based hydrogels have been extensively reviewed in biomedical applications. These hydrogels can be designed in different forms to show optimum performance. For instance, electroactive PSA-based hydrogels respond under an electric stimulus. Such performance can be served in stimulus drug release and determining cell fate. This review classifies and discusses the structure, properties, and applications of the most important polysaccharide-based electroactive hydrogels (agarose, alginate, chitosan, cellulose, and dextran) in medicine, focusing on their usage in tissue engineering, flexible electronics, and drug delivery applications.

Polymer-Based Wound Dressing Materials Loaded with Bioactive Agents: Potential Materials for the Treatment of Diabetic Wounds

Diabetic wounds are severe injuries that are common in patients that suffer from diabetes. Most of the presently employed wound dressing scaffolds are inappropriate for treating diabetic wounds. Improper treatment of diabetic wounds usually results in amputations. The shortcomings that are related to the currently used wound dressings include poor antimicrobial properties, inability to provide moisture, weak mechanical features, poor biodegradability, and biocompatibility, etc. To overcome the poor mechanical properties, polymer-based wound dressings have been designed from the combination of biopolymers (natural polymers) (e.g., chitosan, alginate, cellulose, chitin, gelatin, etc.) and synthetic polymers (e.g., poly (vinyl alcohol), poly (lactic-co-glycolic acid), polylactide, poly-glycolic acid, polyurethanes, etc.) to produce effective hybrid scaffolds for wound management. The loading of bioactive agents or drugs into polymer-based wound dressings can result in improved therapeutic outcomes such as good antibacterial or antioxidant activity when used in the treatment of diabetic wounds. Based on the outstanding performance of polymer-based wound dressings on diabetic wounds in the pre-clinical experiments, the in vivo and in vitro therapeutic results of the wound dressing materials on the diabetic wound are hereby reviewed.

BIOTECHNOLOGICAL ASPECTS OF THE DEVELOPMENT OF A LIQUID FORMULATION OF MULTIFUNCTIONAL ENZYBIOTIC ANTISEPTIC

Aim. Evaluation of biotechnological aspects of the production of a liquid formulation of the multifunctional antiseptic preparation of microbial origin, which can be typified as an enzybiotic; characterization of the enzyme specificity of the studied formulation, stabilization methods, its ability to affect microbial biofilms. Methods. Gel-filtration and electrophoresis were used to study the component composition and the specificity of the enzyme complex of the Streptomyces albus UN 44 producer strain. Proteolytic and staphylolytic activities of individual fractions were determined. The Pseudomonas aeruginosa biofilm and its formation under the effect of various drug formulations were quantitatively evaluated by spectrophotometry. Results. The stability of the liquid formulation of the enzybiotic biosynthesized by S. albus UN 44 was demonstrated. Activity of the formulation could be prolonged and additionally stabilized by adding of 0.5% polyvinyl alcohol. Fractionation of the formulation enzyme complex using gel-filtration revealed the presence of at least three proteinases of different molecular weights (80-100, 24-35 and 20 kDa) and lysoenzymes (18-22 kDa). The effectiveness of the developed liquid antibiotic formulation for the destruction and inhibition (8-10 folds) of the biofilm formation by clinical strains of P. aeruginosa was shown. Conclusions. The broad spectrum, multidirectional mechanisms of antimicrobial and regenerative action of enzybiotic drug, and the possibility of its production directly from the biotechnological process determine the prospects of its manufacturing and use as a multifunctional surface antiseptic.