The emerging progress on wound dressings and their application in clinic wound management

Antibacterial Interactions of Ethanol-Dispersed Multiwalled Carbon Nanotubes with Staphylococcus aureus and Pseudomonas aeruginosa

Infectious diseases are acknowledged as one of the leading causes of death worldwide. Statistics show that the annual death toll caused by bacterial infections has reached 14 million, most of which are caused by drug-resistant strains. Bacterial antibiotic resistance is currently regarded as a compelling problem with dire consequences, which motivates the urgent identification of alternative ways of fighting bacteria. Various types of nanomaterials have been reported to date as efficient antibacterial solutions. Among these, carbon-based nanomaterials, such as carbon nanodots, carbon graphene oxide, and carbon nanotubes (CNTs), have been shown to be effective in killing a wide panel of pathogenic bacteria. With this study, we aim to provide additional insights into this topic of research by investigating the antibacterial activity of a specific type of multiwalled CNTs, with diameters from 50 to 150 nm, against two representative opportunistic pathogens, i.e., the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacterium Pseudomonas aeruginosa, both included among the top antibiotic-resistant pathogens. We also test the synergistic effect of CNTs with different antibiotics commonly used in the treatment of infections caused by S. aureus and/or P. aeruginosa. Additionally, a novel approach for quantitatively analyzing bacterial aggregation in brightfield microscopy images was implemented. This method was utilized to assess the effectiveness of CNTs, either alone or in combination with antibiotics, in dispersing bacterial aggregates. Finally, atomic force microscopy coupled with a newly devised image analysis pipeline was used to examine any potential morphological changes in bacterial cells following exposure to CNTs and antibiotics.

Films based on TEMPO-oxidized chitosan nanoparticles: Obtaining and potential application as wound dressings

A series of novel films based on TEMPO-oxidized chitosan nanoparticles were prepared by casting method. Fourier transform infrared spectroscopy (FTIR) was employed to ascertain the chemical structure of TEMPO-oxidized chitosan. The surface morphology of the TEMPO-oxidized chitosan nanoparticles was analyzed by atomic force microscopy (AFM). The physicochemical (area density, thickness, iodine sorption, roughness), functional (moisture sorption, liquid absorption capacity, weight loss upon contact with the liquid, and water vapor transmission rate), antibacterial, and antioxidant properties of films based on TEMPO-oxidized chitosan nanoparticles were also investigated. The physicochemical properties of the films varied widely: area density ranged from 77.83 ± 0.06 to184.46 ± 0.05 mg/cm2, thickness varied between 80.5 ± 1.6 and 200.5 ± 1.6 μm, iodine sorption spanned from 333.7 ± 2.1 to166.4 ± 2.2 mg I2/g, and roughness ranged from 4.1 ± 0.2 to 5.6 ± 0.3 nm. Similarly, the functional properties also varied significantly: moisture sorption ranged from 4.76 ± 0.03 to 9.62 ± 0.11 %, liquid absorption capacity was between 129.04 ± 0.24 and 159.33 ± 0.73 % after 24 h, weight loss upon contact with the liquid varied between 31.06 ± 0.35 and 45.88 ± 0.58 % after 24 h and water vapor transmission rate ranged from 1220.10 ± 2.91to1407.77 ± 5.22 g/m2 day. Despite the wide variations in physicochemical and functional properties, all films showed maximum bacterial reduction of Staphylococcus aureus and Escherichia coli, although they exhibited low antioxidant activity. The results suggest that the films could be effectively utilized as antibacterial wound dressings.

Electrospun collagen/chitosan composite fibrous membranes for accelerating wound healing

The protein-polysaccharide nanofibers have attracted intensive attention in promoting wound healing, due to their components and nanoscale fibrous structure that mimics the native extracellular matrix (ECM). For the full-thickness wounds, in addition to promoting healing, hemostatic property and antibacterial activity are also of critical importance. However, currently, protein-polysaccharide-based nanofiber membranes exhibit poor mechanical properties, lack inherent hemostatic and antibacterial capabilities, as well as the ability to promote tissue repair. In this study, we developed composited membranes, which were composed of collagen (Col) and chitosan (Chs), through solvent alteration and post-processing, the membranes showed enhanced stability under physiological conditions, proper hydrophilic performance and improved mechanical property. Appropriated porosity and water vapor transmission rate, which benefit to wound healing, were detected among all the membranes except for Col membrane. Aimed at wound dressing, hemocompatibility, antibacterial activity and cell proliferation of the electrospun membranes were evaluated. The results indicated that the Col/Chs composited membranes exhibited superior blood clotting capacity, and the membranes with Chs exceeding 60% possessed sufficient antibacterial activity. Moreover, compared with Chs nanofibers, significant increase in cell grow was detected in Col/Chs (1:3) membrane. Taken together, the electrospun membrane with multiple properties favorable to wound healing, superior blood coagulation, sufficient antibacterial performance and promoting cell proliferation property make it favorable candidate for full-thickness skin wound healing.

CDI crosslinked chitosan/poly (vinyl alcohol) electrospun nanofibers loaded with Achillea millefolium and Viola extract: A promising wound dressing

Biopolymer-based electrospun mats, mimicking the extracellular matrix, have been extensively explored in biomedical applications. This study compares Achillea millefolium (AM) and Viola (V) extracts for developing a biocompatible wound dressing. The extracts were incorporated into a Chitosan/polyvinyl alcohol (CS/PVA) matrix via electrospinning. Crosslinking with Carbonyldiimidazole (CDI) improved chemical stability, water resistance, and biodegradability. The resulting mats exhibited flawless interconnected nanofibers, confirming the presence of AM and Viola extracts as analyzed via FTIR. Significant differences were observed between these two herbal extracts, particularly in mechanical properties, with tensile strengths of 6.9 MPa for AM and 17.2 MPa for Viola. Viola extract demonstrated robust antibacterial properties, producing an 8.2 mm inhibition zone against Staphylococcus aureus, compared to AM's 30 %. The release of therapeutic agents indicated an initial rapid phase, followed by a controlled 72 h release at a consistent rate. Notably, Viola extract led to 80.9 % wound closure on the 10th day, surpassing AM extract at 63.7 %. In contrast, the control group achieved only 32.1 % closure. This comparative study underscores the distinct advantages of AM and Viola extracts in wound dressing applications. While AM presents specific strengths, Viola extract exhibits superior mechanical properties, antibacterial efficacy, and accelerated wound closure, suggesting its potential with significant clinical implications.

Smart Dressings and Their Applications in Chronic Wound Management

During chronic wound healing, the inflammatory phase can endure for extended periods, heavily impeding or halting the process. Regular inspections and dressing changes are crucial. Modern dressings like hydrogels, hydrocolloids, and foam provide protection and an optimal healing environment. However, they have limitations in offering real-time wound bed status and healing rate. Evaluation relies heavily on direct observation, and passive dressings fail to identify subtle healing differences, preventing adaptive adjustments in biological factors and drug concentrations. In recent years, the clinical field recognizes the value of integrating intelligent diagnostic tools into wound dressings. By monitoring biomarkers linked to chronic wounds' inflammatory state, real-time data can be captured, reducing medical interventions and enabling more effective treatment plans. This fosters innovation in chronic wound care. Researchers have developed smart dressings with sensing, active drug delivery, and self-adjustment capabilities. These dressings detect inflammatory markers like temperature, pH, and oxygen content, enhancing drug bioavailability on the wound surface. As wound healing technology evolves, these smart dressings hold immense potential in chronic wound care and treatment. This comprehensive review updates our understanding on the role and mechanism of action of the smart dressings in chronic refractory wounds by summarizing and discussing the latest research progresses, including the intelligent monitoring of wound oxygen content, temperature, humidity, pH, infection, and enzyme kinetics; intelligent drug delivery triggered by temperature, pH, near-infrared, and electricity; as well as the intelligent self-adjustment of pressure and shape. The review also delves into the constraints and future perspectives of smart dressings in clinical settings, thereby advancing the development of smart wound dressings for chronic wound healing and their practical application in clinical practice.

Development and Evaluation of a Novel Antibacterial Wound Dressing: A Powder Preparation Based on Cross-Linked Pullulan with Polyhexamethylene Biguanide for Hydrogel-Transition in Advanced Wound Management and Infection Control

As antibiotic resistance increasingly undermines traditional infection management strategies, there is a critical demand for innovative wound care solutions that address these emerging challenges. This study introduces a novel antibacterial wound dressing based on Cross-Linked Pullulan (Pul) and Polyhexamethylene Biguanide (PHMB) for enhanced wound management and infection control. The dressing's adsorption rate reached 200% of its original weight within 30 min, exceeded 300% after 5 h, and exhibited significant non-Newtonian fluid properties. The dressings were able to release the loaded medication completely within 20 min; additionally, the dressing demonstrated significant antibacterial activity against a broad spectrum of bacteria. Significantly, the therapeutic effects of the Pul-PHMB/GP dressing were evaluated in a mouse model. Compared to untreated wounds, wounds treated with Pul-PHMB/GP exhibited a significant gelation process within 5 min post-treatment and showed a significant increase in wound healing rate within 12 days. This powder preparation overcomes the limitations associated with liquid and gel dressings, notably in storage and precise application, preventing the premature expansion or dissolution often caused by PHMB in high-humidity environments. The powder form can transform into a gel upon contact with wound exudate, ensuring accurate coverage of irregular wounds, such as those from burns or pressure sores, and offers excellent chemical and physical stability in a dry state, which facilitates storage and transport. This makes the dressing particularly suitable for emergency medical care and precision therapy, significantly improving the efficiency and adaptability of wound treatment and providing robust support for clinical treatments and emergency responses.

Preparation of Gel Forming Polymer-Based Sprays for First Aid Care of Skin Injuries

Currently, there are several types of materials for the treatment of wounds, burns, and other topical injuries available on the market. The most used are gauzes and compresses due to their fluid absorption capacity; however, these materials adhere to the surface of the lesions, which can lead to further bleeding and tissue damage upon removal. In the present study, the development of a polymer-based gel that can be applied as a spray provides a new vision in injury protection, respecting the requirements of safety, ease, and quickness of both applicability and removal. The following polymeric sprays were developed to further obtain gels based on different polymers: hydroxypropyl cellulose (HPC), polyvinyl pyrrolidone (PVP) and hydroxypropyl methylcellulose (HPMC) using polyethylene glycol (PEG) as a plasticizer. The developed sprays revealed suitable properties for use in topical injuries. A protective film was obtained when sprayed on a surface through a casting mechanism. The obtained films adhered to the surface of biological tissue (pig muscle), turning into a gel when the exudate was absorbed, and proved to be washable with saline solution and contribute to the clotting process. Moreover, biocompatibility results showed that all materials were biocompatible, as cell viability was over 90% for all the materials.

Acellular embryoid body and hydroxybutyl chitosan composite hydrogels promote M2 macrophage polarization and accelerate diabetic cutaneous wound healing

Diabetic wound healing is delayed due to persistent inflammation, and macrophage-immunomodulating biomaterials can control the inflammatory phase and shorten the healing time. In this study, acellular embryoid bodies (aEBs) were prepared and mixed with thermosensitive hydroxybutyl chitosan (HBC) hydrogels to produce aEB/HBC composite hydrogels. The aEB/HBC composite hydrogels exhibited reversible temperature-sensitive phase transition behavior and a hybrid porous network. In vitro analysis showed that the aEB/HBC composite hydrogels exhibited better antimicrobial activity than the PBS control, aEBs or HBC hydrogels and promoted M0 to M2 polarization but not M1 to M2 macrophage repolarization in culture. The in vivo results showed that the aEB/HBC composite hydrogels accelerated cutaneous wound closure, re-epithelialization, ingrowth of new blood vessels, and collagen deposition and reduced the scar width during wound healing in diabetic mice over time. Macrophage phenotype analysis showed that the aEB/HBC composite hydrogels induce M2 macrophage reactions continually, upregulate M2-related mRNA and protein expression and downregulate M1-related mRNA and protein expression. Therefore, the aEB/HBC composite hydrogels have excellent antimicrobial activity, promote M2 macrophage polarization and accelerate the functional and structural healing of diabetic cutaneous wounds.

A review of the current state of natural biomaterials in wound healing applications

Skin, the largest biological organ, consists of three main parts: the epidermis, dermis, and subcutaneous tissue. Wounds are abnormal wounds in various forms, such as lacerations, burns, chronic wounds, diabetic wounds, acute wounds, and fractures. The wound healing process is dynamic, complex, and lengthy in four stages involving cells, macrophages, and growth factors. Wound dressing refers to a substance that covers the surface of a wound to prevent infection and secondary damage. Biomaterials applied in wound management have advanced significantly. Natural biomaterials are increasingly used due to their advantages including biomimicry of ECM, convenient accessibility, and involvement in native wound healing. However, there are still limitations such as low mechanical properties and expensive extraction methods. Therefore, their combination with synthetic biomaterials and/or adding bioactive agents has become an option for researchers in this field. In the present study, the stages of natural wound healing and the effect of biomaterials on its direction, type, and level will be investigated. Then, different types of polysaccharides and proteins were selected as desirable natural biomaterials, polymers as synthetic biomaterials with variable and suitable properties, and bioactive agents as effective additives. In the following, the structure of selected biomaterials, their extraction and production methods, their participation in wound healing, and quality control techniques of biomaterials-based wound dressings will be discussed.

Nanozyme-Engineered Hydrogels for Anti-Inflammation and Skin Regeneration

Inflammatory skin disorders can cause chronic scarring and functional impairments, posing a significant burden on patients and the healthcare system. Conventional therapies, such as corticosteroids and nonsteroidal anti-inflammatory drugs, are limited in efficacy and associated with adverse effects. Recently, nanozyme (NZ)-based hydrogels have shown great promise in addressing these challenges. NZ-based hydrogels possess unique therapeutic abilities by combining the therapeutic benefits of redox nanomaterials with enzymatic activity and the water-retaining capacity of hydrogels. The multifaceted therapeutic effects of these hydrogels include scavenging reactive oxygen species and other inflammatory mediators modulating immune responses toward a pro-regenerative environment and enhancing regenerative potential by triggering cell migration and differentiation. This review highlights the current state of the art in NZ-engineered hydrogels (NZ@hydrogels) for anti-inflammatory and skin regeneration applications. It also discusses the underlying chemo-mechano-biological mechanisms behind their effectiveness. Additionally, the challenges and future directions in this ground, particularly their clinical translation, are addressed. The insights provided in this review can aid in the design and engineering of novel NZ-based hydrogels, offering new possibilities for targeted and personalized skin-care therapies.

Kick-Starting Wound Healing: A Review of Pro-Healing Drugs

Cutaneous wound healing consists of four stages: hemostasis, inflammation, proliferation/repair, and remodeling. While healthy wounds normally heal in four to six weeks, a variety of underlying medical conditions can impair the progression through the stages of wound healing, resulting in the development of chronic, non-healing wounds. Great progress has been made in developing wound dressings and improving surgical techniques, yet challenges remain in finding effective therapeutics that directly promote healing. This review examines the current understanding of the pro-healing effects of targeted pharmaceuticals, re-purposed drugs, natural products, and cell-based therapies on the various cell types present in normal and chronic wounds. Overall, despite several promising studies, there remains only one therapeutic approved by the United States Food and Drug Administration (FDA), Becaplermin, shown to significantly improve wound closure in the clinic. This highlights the need for new approaches aimed at understanding and targeting the underlying mechanisms impeding wound closure and moving the field from the management of chronic wounds towards resolving wounds.