Antimicrobial Biomaterials for Chronic Wound Care

Advances in Designer Materials for Chronic Wound Healing

Significance: Nonhealing or chronic wounds represent a significant and growing global health concern, imposing substantial burdens on individuals, health care systems, and economies worldwide. Although the standard-of-care treatment involves the application of wound dressings, most dressing materials are not specifically designed to address the pathological processes underlying chronic wounds. This review highlights recent advances in biomaterial design tailored to chronic wound healing. Recent Advances: Chronic wounds are characterized by persistent inflammation, impaired granulation tissue formation, and delayed re-epithelialization. Newly developed designer materials aim to manage reactive oxygen species and extracellular matrix degradation to suppress inflammation while promoting vascularization, cell proliferation, and epithelial migration to accelerate tissue repair. Critical Issues: Designing optimal materials for chronic wounds remains challenging due to the diverse etiology and a multitude of pathological mechanisms underlying chronic wound healing. While designer materials can target specific aberrations, designing a materials approach that restores all aberrant wound-healing processes remains the Holy Grail. Addressing these issues requires a deep understanding of how cells interact with the materials and the complex etiology of chronic wounds. Future Directions: New material approaches that target wound mechanics and senescence to improve chronic wound closure are under development. Layered materials combining the best properties of the approaches discussed in this review will pave the way for designer materials optimized for chronic wound healing.

Polycaprolactone/sodium alginate coaxial wet-spun fibers modified with carbon nanofibers and ceftazidime for improved clotting and infection control in wounds

Chronic wounds (CWs) are a significant public health concern and affect 1-2% of the world's population. They are responsible for high morbidity and mortality rates. Bacterial infections caused by Staphylococcus aureus and Pseudomonas aeruginosa are very common in CWs and prevent normal wound healing steps from taking place. Carbon nanofibers (CNFs) have attracted interest due to their inherent antibacterial and blood clotting abilities, as well as mechanical strength. The aim of this research was to engineer coaxial fibers by wet-spinning as new platforms for drug delivery in CW care (promoting rapid blood clotting and consequent tissue regeneration). Coaxial fibers were produced with an outer layer (shell) made of a mechanically resilient polycaprolactone (PCL at 10 wt%) reinforced with carbon nanofibers (CNFs at 50, 100, and 150 μg mL-1), while the inner layer (core) was made of a highly hydrated mixture of 2 wt% sodium alginate (SA) loaded with ceftazidime (CZ) at 128 μg mL-1 (minimum bactericidal concentration). The fibers' double-layer structure was verified by scanning electron microscopy. Core-shell fibers were deemed highly flexible and mechanically resilient and resistant to rupture, with such properties being improved with the incorporation of CNFs. Most fibers preserved their structural integrity after 28 days of incubation in physiological-like medium. Furthermore, data reported the ability of CZ combined with CNFs to fight microbial proliferation and showed that the presence of CNFs promoted blood clotting, with PCL/CNFs50 being the most effective from the group. It was found that higher concentrations of CNFs had a detrimental effect, highlighting a concentration-dependent response. The presence of PLC in the fibers resulted in a mitigation of the CNFs' cytotoxic impact on keratinocytes. The incorporation of CZ had no effect on the metabolic activity of the cells. Overall, the results demonstrated the potentialities of the engineered coaxial fibers for applications in wound care.

Accelerated dermal wound healing in diabetic mice by a H2O2-generating catechol-functionalized gelatin microgel

Physically crosslinked gelatin microgels were functionalized with a bioadhesive molecule, catechol, to study the effect of in situ generated H2O2 on full-thickness wound repair in diabetic mice. Due to the physically crosslinked nature of the microgels, they transition into a hydrogel film upon hydration. The formation of a hydrogel film was confirmed by the changes in their morphology and viscoelastic properties. Additionally, these microgels released up to 86 μM of H2O2 as a result of catechol autoxidation. The generated H2O2 completely eradicated Staphylococcus epidermidis with an initial concentration of 103 CFU mL-1. These microgels were not cytotoxic and promoted VEGF upregulation in immortalized human keratinocytes (HaCaT) in vitro. When the microgels were applied to a full-thickness dermal wound in diabetic mice, dermal wound closure was accelerated over 14 days, achieving a wound closure of 90% based on the wound area. Microgel-treated wounds also resulted in complete re-epithelialization and regeneration of new dermal tissues with morphology and structure resembling those of native tissues. These results indicate that the release of micromolar concentrations of H2O2 can accelerate wound healing in a healing-impaired animal.

Enhancing burn wound care with pre-crosslinked 3D-printed patches: Bromelain delivery and aloe vera bioactives integration for improved healing outcomes

Burn wounds remain a major clinical challenge due to the limitations of traditional dressings, which often fail to address the diverse needs of patients and varying wound types. This study aimed to advance burn care by developing a 3D-printed patch incorporating natural bioactive compounds from bromelain and aloe vera. The patch was formulated using pre-crosslinked chitosan and alginate hydrogels to ensure suitability for 3D printing and subsequent use. Rheological analysis revealed weak gel behaviour and shear-thinning properties, ensuring excellent printability. The patches exhibited outstanding swelling behaviour and controlled degradation (30 %), alongside notable antioxidant and anti-inflammatory potential, with a polyphenolic content of 1.43 ± 0.07 mg CAE/g and effective scavenging of DPPH, ABTS, and NO radicals, with IC50 values of 29.51 ± 0.30, 10.31 ± 0.28, and 5.94 ± 0.42 mg/mL, respectively. Bioactive compounds from bromelain were consistently released across various pH levels, supporting their therapeutic efficacy. Cell viability studies confirmed strong support for cell growth, while in vitro scratch tests demonstrated biocompatibility and promotion of wound closure. Histological analysis of ex vivo burn models revealed cellular necrosis and protein denaturation characteristic of burn wounds. Application of the patches significantly improved epidermal morphology and enhanced proliferation markers such as Ki67 and α-SMA, indicative of accelerated wound healing. While further clinical validation is needed, these findings underscore the potential of the 3D-printed patches as an innovative solution for burn wound care, offering improved bioactive delivery and enhanced healing outcomes compared to conventional dressings.

Glucose-activated self-cascade antibacterial and pro-angiogenesis nanozyme-functionalized chitosan-arginine thermosensitive hydrogel for chronic diabetic wounds healing

Affected by persistent hyperglycemia, diabetic neuropathy, and vasculopathy hinder the progression of wound healing by exacerbating susceptibility to recurrent bacterial infection and impairing vascularization. In order to cater to the requirements of diabetic chronic wound healing at various stages, we designed an antibacterial and pro-angiogenic wound dressing with localized glucose-lowering capacity. In this study, we constructed a copper-based metal-organic framework (MOF) nanozyme and loaded with glucose oxidase (GOX) to prepare Cu-MOF/GOX, which was subsequently integrated with CS-Arg (chitosan modified by L-Arginine) and Pluronic (F127) to fabricate multifunctional Cu-MOF/GOX-Gel thermosensitive hydrogel. The GOX generated H2O2 (hydrogen peroxide) and gluconic acid by consuming high blood glucose at the wound site, thus initiating an efficient antibacterial self-cascade catalytic in the initial stages of wound healing. With the further catalysis of in situ generated H2O2, NO (nitric oxide) was gradually released from the hydrogel, facilitating angiogenesis and accumulation of collagen, thereby expediting subsequent phases of wound healing. Overall, the Cu-MOF/GOX-Gel exhibits a comprehensive ability to locally regulate blood glucose levels, while also synergistically promoting antibacterial activity and angiogenesis, that effectively chronic diabetic wounds healing.

Machine learning-driven discovery of novel therapeutic targets in diabetic foot ulcers

BACKGROUND

To utilize machine learning for identifying treatment response genes in diabetic foot ulcers (DFU).

METHODS

Transcriptome data from patients with DFU were collected and subjected to comprehensive analysis. Initially, differential expression analysis was conducted to identify genes with significant changes in expression levels between DFU patients and healthy controls. Following this, enrichment analyses were performed to uncover biological pathways and processes associated with these differentially expressed genes. Machine learning algorithms, including feature selection and classification techniques, were then applied to the data to pinpoint key genes that play crucial roles in the pathogenesis of DFU. An independent transcriptome dataset was used to validate the key genes identified in our study. Further analysis of single-cell datasets was conducted to investigate changes in key genes at the single-cell level.

RESULTS

Through this integrated approach, SCUBE1 and RNF103-CHMP3 were identified as key genes significantly associated with DFU. SCUBE1 was found to be involved in immune regulation, playing a role in the body's response to inflammation and infection, which are common in DFU. RNF103-CHMP3 was linked to extracellular interactions, suggesting its involvement in cellular communication and tissue repair mechanisms essential for wound healing. The reliability of our analysis results was confirmed in the independent transcriptome dataset. Additionally, the expression of SCUBE1 and RNF103-CHMP3 was examined in single-cell transcriptome data, showing that these genes were significantly downregulated in the cured DFU patient group, particularly in NK cells and macrophages.

CONCLUSION

The identification of SCUBE1 and RNF103-CHMP3 as potential biomarkers for DFU marks a significant step forward in understanding the molecular basis of the disease. These genes offer new directions for both diagnosis and treatment, with the potential for developing targeted therapies that could enhance patient outcomes. This study underscores the value of integrating computational methods with biological data to uncover novel insights into complex diseases like DFU. Future research should focus on validating these findings in larger cohorts and exploring the therapeutic potential of targeting SCUBE1 and RNF103-CHMP3 in clinical settings.

Antimicrobial Resistance: What Lies Beneath This Complex Phenomenon?

Antimicrobial Resistance (AMR) has evolved from a mere concern into a significant global threat, with profound implications for public health, healthcare systems, and the global economy. Since the introduction of antibiotics between 1945 and 1963, their widespread and often indiscriminate use in human medicine, agriculture, and animal husbandry has led to the emergence and rapid spread of antibiotic-resistant genes. Bacteria have developed sophisticated mechanisms to evade the effects of antibiotics, including drug uptake limitation, drug degradation, target modification, efflux pumps, biofilm formation, and outer membrane vesicles production. As a result, AMR now poses a threat comparable to climate change and the COVID-19 pandemic, and projections suggest that death rates will be up to 10 million deaths annually by 2050, along with a staggering economic cost exceeding $100 trillion. Addressing AMR requires a multifaceted approach, including the development of new antibiotics, alternative therapies, and a significant shift in antibiotic usage and regulation. Enhancing global surveillance systems, increasing public awareness, and prioritizing investments in research, diagnostics, and vaccines are critical steps. By recognizing the gravity of the AMR threat and committing to collaborative action, its impact can be mitigated, and global health can be protected for future generations.

Modulations of the skin microbiome in skin disorders: A narrative review from a wound care perspective

The cutaneous microbiome represents a highly dynamic community of bacteria, fungi and viruses. Scientific evidence, particularly from the last two decades, has revealed that these organisms are far from being inconsequential microscopic hitchhikers on the human body, nor are they all opportunistic pathogens waiting for the chance to penetrate the skin barrier and cause infection. In this review, we will describe how dermatological diseases have been found to be associated with disruptions and imbalances in the skin microbiome and how this new evidence had shaped the diagnosis and clinical practice relating to these disorders. We will identify the microbial agents which have been found to directly exacerbate skin diseases, as well as those which can ameliorate many of the symptoms associated with dermatological disorders. Furthermore, we will discuss the studies which suggest that bacteriotherapy, either by topical use of probiotics or by bacteria-derived compounds, can rectify skin microbial imbalances, thereby offering a promising alternative to antibiotic treatment and reducing the risks of antibiotic resistance.

Circular economy reinforcement through molecular fabrication of textile wastes with microbial synthesized ZnO nanoparticles to have multifunctional properties

The fibrous wastes generated from the mills of textile production can be recycled and converted into high add-values products to be implemented in several applications. The current study aimed to employ commercial free cellulase enzyme to partially hydrolyze (activate) the polyester cotton blended (PET/C) fibrous wastes by creation functional groups such as OH and COOH on their surfaces. The activated fibrous wastes were then modified by coating with ZnO nanoparticles (ZnO-NPs) biosynthesized by actinobacterial cultures free supernatant. The isolate was identified as Streptomyces pseudogriseolus with accession number of OR574241. The conditions that influence the actino-synthesis of ZnO-NPs were optimized and the product was characterized using spectroscopic vision, FTIR, XRD, TEM and SEM. The characteristic ZnO peaks were obviously observed by EDX analysis with 0.38 and 0.75% (wt%), respectively. TEM analyses proved the nanoscale of ZnO-NPs (5-15 nm) which was followed by cytotoxic evaluation for the produced NPs. Fortunately, the tested actino-ZnO-NPs didn't have any cytotoxicity against human normal fibroblast cell line (BJ1), which means that the product can be safely used in a direct-contact with human skin. The treated PET/C blended waste fabrics coated with ZnO-NPs showed high antimicrobial activity and ultraviolet protection values after functionalization by cellulase. EDX analysis demonstrates the presence of Zn peaks on the coated fabrics compared with their absence in blank and control samples, while SEM images showed the formation of a thin layer of ZnO-NPs on the fabric surface. The obtained smart textile can be applied several needed sectors.

In Vitro Biological Evaluation of an Alginate-Based Hydrogel Loaded with Rifampicin for Wound Care

We report a biocompatible hydrogel dressing based on sodium alginate-grafted poly(N-vinylcaprolactam) prepared by encapsulation of Rifampicin as an antimicrobial drug and stabilizing the matrix through the repeated freeze-thawing method. The hydrogel structure and polymer-drug compatibility were confirmed by FTIR, and a series of hydrogen-bond-based interactions between alginate and Rifampicin were identified. A concentration of 0.69% Rifampicin was found in the polymeric matrix using HPLC analysis and spectrophotometric UV-Vis methods. The hydrogel's morphology was evaluated by scanning electron microscopy, and various sizes and shapes of pores, ranging from almost spherical geometries to irregular ones, with a smooth surface of the pore walls and high interconnectivity in the presence of the drug, were identified. The hydrogels are bioadhesive, and the adhesion strength increased after Rifampicin was encapsulated into the polymeric matrix, which suggests that these compositions are suitable for wound dressings. Antimicrobial activity against S. aureus and MRSA, with an increased effect in the presence of the drug, was also found in the newly prepared hydrogels. In vitro biological evaluation demonstrated the cytocompatibility of the hydrogels and their ability to stimulate cell multiplication and mutual cell communication. The in vitro scratch assay demonstrated the drug-loaded alginate-grafted poly(N-vinylcaprolactam) hydrogel's ability to stimulate cell migration and wound closure. All of these results suggest that the prepared hydrogels can be used as antimicrobial materials for wound healing and care applications.

Neurorestorative Approaches for Ischemic StrokeChallenges, Opportunities, and Recent Advances

Despite recent advances in acute stroke management, most patients experiencing a stroke will suffer from residual brain damage and functional impairment. Addressing those residual deficits would require neurorestoration, i.e., rebuilding brain tissue to repair the structural brain damage caused by stroke. However, there are major pathobiological, anatomical and technological hurdles making neurorestorative approaches remarkably challenging, and true neurorestoration after larger ischemic lesions could not yet be achieved. On the other hand, there has been steady advancement in our understanding of the limits of tissue regeneration in the adult mammalian brain as well as of the fundamental organization of brain tissue growth during embryo- and ontogenesis. This has been paralleled by the development of novel animal models to study stroke, advancement of biomaterials that can be used to support neurorestoration, and in stem cell technologies. This review gives a detailed explanation of the major hurdles so far preventing the achievement of neurorestoration after stroke. It will also describe novel concepts and advancements in biomaterial science, brain organoid culturing, and animal modeling that may enable the investigation of post-stroke neurorestorative approaches in translationally relevant setups. Finally, there will be a review of recent achievements in experimental studies that have the potential to be the starting point of research and development activities that may eventually bring post-stroke neurorestoration within reach.

Challenges and Pitfalls of Research Designs Involving Magnesium-Based Biomaterials: An Overview

Magnesium-based biomaterials hold remarkable promise for various clinical applications, offering advantages such as reduced stress-shielding and enhanced bone strengthening and vascular remodeling compared to traditional materials. However, ensuring the quality of preclinical research is crucial for the development of these implants. To achieve implant success, an understanding of the cellular responses post-implantation, proper model selection, and good study design are crucial. There are several challenges to reaching a safe and effective translation of laboratory findings into clinical practice. The utilization of Mg-based biomedical devices eliminates the need for biomaterial removal surgery post-healing and mitigates adverse effects associated with permanent biomaterial implantation. However, the high corrosion rate of Mg-based implants poses challenges such as unexpected degradation, structural failure, hydrogen evolution, alkalization, and cytotoxicity. The biocompatibility and degradability of materials based on magnesium have been studied by many researchers in vitro; however, evaluations addressing the impact of the material in vivo still need to be improved. Several animal models, including rats, rabbits, dogs, and pigs, have been explored to assess the potential of magnesium-based materials. Moreover, strategies such as alloying and coating have been identified to enhance the degradation rate of magnesium-based materials in vivo to transform these challenges into opportunities. This review aims to explore the utilization of Mg implants across various biomedical applications within cellular (in vitro) and animal (in vivo) models.

Pyoderma Gangrenosum: The Impact of Treatment Non-adherence on Disease Progression

Pyoderma gangrenosum (PG) is a rare, ulcerative, rapidly progressing, destructive, inflammatory cutaneous disease that is both diagnostically and therapeutically challenging. Due to the lack of standardized diagnostic criteria or conclusive guidelines for patient management, clinicians often find themselves without reliable tools for the daily management of PG patients. Additionally, the lack of strict therapeutic compliance in patients with this diagnosis might contribute to a catastrophic evolution of the condition. We report a case of ulcerative PG that is illustrative of the inherent challenges posed by patients frequently changing healthcare providers and treatment regimens, displaying inconsistency and non-adherence. Such behaviors can lead to the loss of disease control, particularly in the context of extensive or rapidly progressing PG, ultimately culminating in the development of mutilating forms of this disease.

Chronic venous insufficiency and venous leg ulcers: Aetiology, on the pathophysiology-based treatment

The chronic venous disease covers a wide spectrum of venous disorders that are characterized by severely impaired blood return that primarily affects veins in the lower extremities. Morphological and functional abnormalities of the venous system led to chronic venous insufficiency (CVI), and present as leg heaviness/achiness, edema, telangiectasia, and varices. The term 'chronic venous insufficiency' (CVI) refers to a disease of greater severity. Venous dysfunction is associated with venous hypertension and is associated with venous reflux due to poorly functioning or incompetent venous valves, which ultimately reduces venous return, leading to a cascade of morphological, physiological, and histologic abnormalities such as blood pooling, hypoxia, inflammation, swelling, skin changes (lipodermatosclerosis), and in severe cases, venous leg ulcers (VLU). This review summarizes recent knowledge about the aetiology, risk factors, and pathophysiology of VLU and compared the possibilities of their treatment.

A Re-Purposing Strategy: Sub-Lethal Concentrations of an Eicosanoid Derived from the Omega-3-Polyunsaturated Fatty Acid Resolvin D1 Affect Dual Species Biofilms

The fungal species Candida parapsilosis and the bacterial species Staphylococcus aureus may be responsible for hospital-acquired infections in patients undergoing invasive medical interventions or surgical procedures and often coinfect critically ill patients in complicating polymicrobial biofilms. The efficacy of the re-purposing therapy has recently been reported as an alternative to be used. PUFAs (polyunsaturated fatty acids) may be used alone or in combination with currently available traditional antimicrobials to prevent and manage various infections overcoming antimicrobial resistance. The objectives of the study were to evaluate the effects of Resolvin D1 (RvD1) as an antimicrobial on S. aureus and C. parapsilosis, as well as the activity against the mixed biofilm of the same two species. Microdilution assays and time-kill growth curves revealed bacterial and fungal inhibition at minimum concentration values between 5 and 10 μg mL-1. In single-species structures, an inhibition of 55% and 42% was reported for S. aureus and C. parapsilosis, respectively. Moreover, RvD1 demonstrated an eradication capacity of 60% and 80% for single- and mixed-species biofilms, respectively. In association with the inhibition activity, a downregulation of genes involved in biofilm formation as well as ROS accumulation was observed. Eradication capability was confirmed also on mature mixed biofilm grown on silicone platelets as shown by scanning electron microscopy (SEM). In conclusion, RvD1 was efficient against mono and polymicrobial biofilms in vitro, being a promising alternative for the treatment of mixed bacterial/fungal infections.