Preparation of biocompatible wound dressings with dual release of antibiotic and platelet-rich plasma for enhancing infected wound healing

Cotton Fabric-Reinforced Hydrogels with Excellent Mechanical and Broad-Spectrum Photothermal Antibacterial Properties

Antibacterial hydrogel wound dressings hold great potential in eliminating bacteria and accelerating the healing process. However, it remains a challenge to fabricate hydrogel wound dressings that simultaneously exhibit excellent mechanical and photothermal antibacterial properties. Here we report the development of polydopamine-functionalized graphene oxide (rGO@PDA)/calcium alginate (CA)/Polypyrrole (PPy) cotton fabric-reinforced hydrogels (abbreviated as rGO@PDA/CA/PPy FHs) for tackling bacterial infections. The mechanical properties of hydrogels were greatly enhanced by cotton fabric reinforcement and an interpenetrating structure, while excellent broad-spectrum photothermal antibacterial properties based on the photothermal effect were obtained by incorporating PPy and rGO@PDA. Results indicated that rGO@PDA/CA/PPy FHs exhibited superior tensile strength in both the warp (289 ± 62.1 N) and weft directions (142 ± 23.0 N), similarly to cotton fabric. By incorporating PPy and rGO@PDA, the swelling ratio was significantly decreased from 673.5% to 236.6%, while photothermal conversion performance was significantly enhanced with a temperature elevated to 45.0 °C. Due to the synergistic photothermal properties of rGO@PDA and PPy, rGO@PDA/CA/PPy FHs exhibited excellent bacteria-eliminating efficiency for S. aureus (0.57%) and E. coli (3.58%) after exposure to NIR for 20 min. We believe that the design of fabric-reinforced hydrogels could serve as a guideline for developing hydrogel wound dressings with improved mechanical properties and broad-spectrum photothermal antibacterial properties for infected-wound treatment.

The effect of Bletilla striata polysaccharide on the physical and healing properties of curdlan-based hydrogel for wound healing

Bletilla striata polysaccharide (BSP) was added to curdlan to form a blend hydrogel through a simple heating-cooling procedure to improve the hydrophilicity and healing efficacy of curdlan-based hydrogel used in wound healing. We explored the interplay between BSP and curdlan, studied how BSP concentration affects the physical properties and microstructures of hydrogels, and examined the biocompatibility and healing properties of the blend hydrogel. It was proved that the hydrogel framework was primarily formed by ordered arranged curdlan molecules, with BSP uniformly dispersed and intertwined with curdlan through hydrogen bonding. This effectively improved its hydrophilicity and strengthened the microstructure. Curdlan was found to be compatible with BSP. The blend hydrogel B3Cd3 (containing 1.5% BSP and 1.5% curdlan, w/v) was identified as the optimal formulation based on its higher water adsorption, water retention, thermal stability and interconnected microstructure, and was thus selected for further research. In vitro experiments revealed the highest cell viability of L929 in B3Cd3 extracts compared to those extracts of single-component curdlan hydrogel (Cd). In vivo, animal studies indicated that the B3Cd3 accelerated wound healing compared to the control group by improving re-epithelialization and blood vessel regeneration. On Days 3 and 11, the therapeutic benefits of B3Cd3 exceeded those of the Cd group, and no significant differences were observed in wound healing rates between the B and B3Cd3 groups from Day 7. The study proves that BSP enhances the physical and healing properties, as well as cell proliferation, of the curdlan-based hydrogel. The blend hydrogel B3Cd3, with its exceptional properties, holds potential for future application as a material for non-infected wound healing.

Coaxial electrospun PGS/PCL and PGS/PGS-PCL nanofibrous membrane containing platelet-rich plasma for skin tissue engineering

Wound healing will be enhanced using structures with therapeutic effects. This study fabricated a novel nanofibrous scaffold for skin tissue regeneration using a coaxial structure polyglycerol sebacate (PGS)/platelet-rich plasma (PRP) was embedded in the core and two different compositions were selected for the shell; in one group, polycaprolactone (PCL), and in the other group, PGS/PCL blend was used. The physical, mechanical behavior, drug delivery patterns, and cell response of scaffolds were evaluated. Results revealed that by adding PRP to the core and PGS to the shell, fiber diameters decreased to 260.8 ± 31.3 nm. It also decreased the water contact angle from 66° to 32°, that is ideal candidate for cell attachment. The drug release showed a burst release pattern in the first 30 min, followed by a continuous and slow release during the first day. Adding PGS to the shell decreased the elastic modulus, and its value reached about 500 kPa, which is near the skin elastic modulus and will lead to greater mechanical compatibility for cell proliferation. Particularly, the addition of PRP to the fiber structure enhanced the cell viability and cell adhesion with a suitable morphology. Based on the results, nanofibrous PGS-PRP/PGS-PCL dressing can enhance skin tissue regeneration.

Airbrushed nanofibers with bioactive core and antibacterial shell for wound healing application

Acute and chronic wounds are vulnerable to infection and delayed healing and require critical care and advanced wound protection. To overcome the challenges, dual therapy of antibacterial and growth factors will be a novel wound care strategy. The present study explores airbrushed core-shell nanofiber for dual delivery of epidermal growth factor (EGF) and amoxicillin (AMOX) in a sustained manner. A blend of polycaprolactone (PCL)-polyethylene oxide (PEO) was used to prepare the shell compartment for amoxicillin loading and poly-DL-lactide (PDLLA) core for EGF loading by using a customized airbrush setup. Characterization result shows a uniform distribution of nanofibers ranging between 200 and 500 nm in diameter. Amoxicillin loading in the shell compartment offers an initial burst release followed by a sustained release for up to 14 days. Whereas EGF in the core part shows a continuous sustained release throughout the release study.In-vitrostudy indicates the biocompatibility of EGF-AMOX loaded core-shell nanofibers with human dermal fibroblast cell (HDF) cells and a higher cellular proliferation compared to control samples. Gene expression data show an increase in fold change of collagen I and tropoelastin expression, indicating the regenerative properties of EGF-AMOX encapsulated nanofiber. The combination of bioactive core (EGF) and antibiotic shell (amoxicillin) in an airbrushed nanofibrous scaffold is a novel approach, which is the first time explored to deliver sustainable therapy to treat skin wounds. Our results demonstrate that PCL-PEO-Amoxicillin/PDLLA-EGF-loaded core-shell nanofibers are promising dual therapy scaffolds to deliver effective skin wound care, with the possibility of direct deposition on the wound.

Clinical Study of Platelet-Rich Plasma (PRP) for Lower Extremity Venous Ulcers: A Meta-Analysis and Systematic Review

To systematically evaluate the clinical effects of platelet-rich plasma in the treatment of lower limb venous ulcers by applying a meta-analysis method. The Pubmed, Cochrance Library, Embase, and OVID EBM Reviews databases were searched for the search terms'platelet-rich plasma" or "Plasma, Platelet-Rich" or "Platelet Rich Plasma" and "lower extremity venous ulcers' or "Leg Ulcers' or "Ulcer, Leg", and a meta-analysis was performed on the published research literature on platelet-rich plasma for lower extremity venous ulcers from January 1900 to April 2021. The outcome indicators were: post-treatment trauma area and healing rate. Revman 5.3 statistical software was applied for meta-analysis. A total of 294 patients with lower extremity venous ulcers were included in six publications, including 148 patients in the experimental group treated with PRP versus 146 patients in the control group treated with conventional therapy. There was a statistically significant difference in the Formula of an ellipse at the end of treatment (CM²) between the experimental group and the control group, with a mean difference of -1.19 (95% CI -1.80 to -0.58, P = .0001; 6 studies, 294 participants moderate quality of evidence). The difference between the healing rate of the experimental group and the control group was statistically significant, with a risk ratio (RR) of 5.73 (95% CI 3.29 - 9.99, P < .00001; 5 studies, 248 participants moderate quality of evidence).There may be publication bias for both Formula of an ellipse at the end of treatment and healing rate. This comprehensive meta-analysis of available evidence suggests that the application of PRP for lower extremity venous ulcers accelerates the wound healing process and improves wound healing rates.

Combining the dual antibacterial and regenerative activities of platelet-rich plasma with β-lactams to mitigate MRSA-infected skin wounds

The emergence of multidrug-resistant bacteria contributes to the necessity of developing novel infection treatment approaches. This study was designed to evaluate the antimicrobial and wound healing activities of platelet-rich plasma (PRP) in combination with β-lactams (ampicillin and/or oxacillin) for the application on methicillin-resistant Staphylococcus aureus (MRSA)-infected skin. PRP was collected from the peripheral blood of healthy donors. The anti-MRSA activity was tested through a growth inhibition curve, colony-forming unit (CFU), and SYTO 9 assay. The PRP incorporation lowered the minimum inhibitory concentration (MIC) of ampicillin and oxacillin against MRSA. The combination of β-lactams together with PRP showed a three-log CFU reduction of MRSA. The major components of PRP for eliminating MRSA were found to be the complement system and iron sequestration proteins, according to the proteomic analysis. The adhesive bacterial colony in the microplate was decreased from 2.9 × 107 to 7.3 × 105 CFU after the treatment of cocktails containing β-lactams and PRP. The cell-based study indicated that keratinocyte proliferation was stimulated by PRP. The in vitro scratch and transwell experiments revealed that PRP improved keratinocyte migration. In the MRSA-infected mouse skin model, PRP appeared to show a synergistic effect for wound area reduction by 39% when combined with β-lactams. The MRSA burden in the infected area was lessened two-fold after topical administration of the combined β-lactams and PRP. PRP inhibited macrophage infiltration in the wound site to shorten the inflammatory phase and accelerate the initiation of the proliferative phase. No skin irritation was detected with the topical delivery of this combination. Our findings suggested that β-lactams plus PRP was applicable to alleviate the problems associated with MRSA via dual antibacterial and regenerative activities.

Platelet-rich plasma-loaded bioactive chitosan@sodium alginate@gelatin shell-core fibrous hydrogels with enhanced sustained release of growth factors for diabetic foot ulcer healing

The ability of autologous platelet-rich plasma (PRP) gel to promote rapid wound healing without immunological rejection has opened new avenues for the treatment of diabetic foot wounds. However, PRP gel still suffers from the quick release of growth factors (GFs) and requires frequent administration, thus resulting in decreased wound healing efficiency, higher cost as well as greater pain and suffering for the patients. In this study, the flow-assisted dynamic physical cross-linked coaxial microfluidic three-dimensional (3D) bio-printing technology, combined with the calcium ion chemical dual cross-linking method was developed to design PRP-loaded bioactive multi-layer shell-core fibrous hydrogels. The prepared hydrogels exhibited outstanding water absorption-retention capacity, good biocompatibility as well as a broad-spectrum antibacterial effect. Compared with clinical PRP gel, these bioactive fibrous hydrogels displayed a sustained release of GFs, reducing the administration frequency by 33 % availably during the wound treatment, but more prominent therapeutic effects such as effective reduced inflammation, in addition to promoting the growth of granulation tissue and angiogenesis, the formation of high-density hair follicles, and the generation of regular ordered and high-density collagen fiber network, which suggested great promise as exceptional candidates for treatment of diabetic foot ulcer in clinical settings.

Mild Heat-Assisted Polydopamine/Alginate Hydrogel Containing Low-Dose Nanoselenium for Facilitating Infected Wound Healing

In clinical practice, it has become urgent to develop multifunctional wound dressings that can combat infection and prompt wound healing simultaneously. In this study, we proposed a polydopamine/alginate/nanoselenium composite hydrogel (Alg-PDA-Se) for the treatment of infected wounds. In particular, polydopamine endows the composite hydrogel with controllable near-infrared photothermal properties, while low-dosage selenium nanoparticles (Se NPs) offer excellent anti-oxidation, anti-inflammatory, pro-proliferative, pro-migration, and pro-angiogenic performances, which are verified by multiple cells, including macrophages, fibroblasts, and endothelial cells. More interestingly, the combination of mild temperature with low-dosage Se NPs produces a synergistic effect on combating both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and promoting the healing of bacteria-infected wounds in vivo. We anticipate that the designed composite hydrogel might be a potential candidate for anti-infection bioactive dressing.

Effect and Mechanism of Dragon's Blood on Wound Healing of Patients with Stress Hand Injury

This study aimed to explore the effect and mechanism of Dragon's Blood on wound healing in patients with a pressure hand injury. A total of 120 patients with pressure hand injury treated in our hospital were randomly divided into two groups. Sixty patients in the control group were dressed with sterile gauze, and 60 patients in the observation group were smeared with blood exhaustion. The clinical effects and serological indexes of the two groups were compared, and the mechanism of wound healing was analyzed. The results showed that the treatment effective rate of the control group was 80% and that of the observation group was 93.33%. The treatment effective rate of the observation group was dramatically higher (P < 0.05). The number of patients with good granulation tissue in the observation group was 53, which was dramatically greater than that in the control group. The number of patients with a small amount of wound exudation was 51, which was dramatically greater than that in the control group (P < 0.05). After treatment, the levels of matrix metalloproteinase (MMP-3), vascular endothelial growth factor (VEGF), and transforming growth factor B1 (TGF-B1) in the observation group increased more dramatically (P < 0.05). The level of tissue inhibitor of metalloproteinase-1 (TIMP-1) decreased to 617.23 ng/L in the observation group, and the degree of reduction was more obvious (P < 0.05). Notably, Dragon's Blood promoted wound healing at the injury site by increasing the levels of MMP-3, VEGF, and TGF-B1and decreasing TIMP-1. The area of wound reduction in the observation group was 0.27 cm², and the reduction was more obvious (P < 0.05). The healing time of pressure hand injury in the observation group was 15.27 days, which was dramatically shorter (P < 0.05). In summary, Dragon's Blood had a good effect on the healing of the injured site in patients with pressure hand injury, which is worthy of promotion.

Case report: Long-term follow-up of a large full-thickness skin defect treated with a photosynthetic scaffold for dermal regeneration

It is broadly described that almost every step of the regeneration process requires proper levels of oxygen supply; however, due to the vascular disruption in wounds, oxygen availability is reduced, being detrimental to the regeneration process. Therefore, the development of novel biomaterials combined with improved clinical procedures to promote wound oxygenation is an active field of research in regenerative medicine. This case report derives from a cohort of patients enrolled in a previously published ongoing phase I clinical trial (NCT03960164), to assess safety of photosynthetic scaffolds for the treatment of full skin defects. Here, we present a 56 year old patient, with a scar contracture in the cubital fossa, which impaired the elbow extension significantly affecting her quality of life. As part of the treatment, the scar contracture was removed, and the full-thickness wound generated was surgically covered with a photosynthetic scaffold for dermal regeneration, which was illuminated to promote local oxygen production. Then, in a second procedure, an autograft was implanted on top of the scaffold and the patient’s progress was followed for up to 17 months. Successful outcome of the whole procedure was measured as improvement in functionality, clinical appearance, and self-perception of the treated area. This case report underscores the long-term safety and applicability of photosynthetic scaffolds for dermal regeneration and their stable compatibility with other surgical procedures such as autograft application. Moreover, this report also shows the ability to further improve the clinical outcome of this procedure by means of dermal vacuum massage therapy and, more importantly, shows an overall long-term improvement in patient´s quality of life, supporting the translation of photosynthetic therapies into human patients.

Borrowing the Features of Biopolymers for Emerging Wound Healing Dressings: A Review

Wound dressing design is a dynamic and rapidly growing field of the medical wound-care market worldwide. Advances in technology have resulted in the development of a wide range of wound dressings that treat different types of wounds by targeting the four phases of healing. The ideal wound dressing should perform rapid healing; preserve the body’s water content; be oxygen permeable, non-adherent on the wound and hypoallergenic; and provide a barrier against external contaminants—at a reasonable cost and with minimal inconvenience to the patient. Therefore, choosing the best dressing should be based on what the wound needs and what the dressing does to achieve complete regeneration and restoration of the skin’s structure and function. Biopolymers, such as alginate (ALG), chitosan (Cs), collagen (Col), hyaluronic acid (HA) and silk fibroin (SF), are extensively used in wound management due to their biocompatibility, biodegradability and similarity to macromolecules recognized by the human body. However, most of the formulations based on biopolymers still show various issues; thus, strategies to combine them with molecular biology approaches represent the future of wound healing. Therefore, this article provides an overview of biopolymers’ roles in wound physiology as a perspective on the development of a new generation of enhanced, naturally inspired, smart wound dressings based on blood products, stem cells and growth factors.

The Expanded Role of Chitosan in Localized Antimicrobial Therapy

Chitosan is one of the most studied natural origin polymers for biomedical applications. This review focuses on the potential of chitosan in localized antimicrobial therapy to address the challenges of current rising antimicrobial resistance. Due to its mucoadhesiveness, chitosan offers the opportunity to prolong the formulation residence time at mucosal sites; its wound healing properties open possibilities to utilize chitosan as wound dressings with multitargeted activities and more. We provide an unbiased overview of the state-of-the-art chitosan-based delivery systems categorized by the administration site, addressing the site-related challenges and evaluating the representative formulations. Specifically, we offer an in-depth analysis of the current challenges of the chitosan-based novel delivery systems for skin and vaginal infections, including its formulations optimizations and limitations. A brief overview of chitosan's potential in treating ocular, buccal and dental, and nasal infections is included. We close the review with remarks on toxicity issues and remaining challenges and perspectives.

Construction of a multifunctional 3D nanofiber aerogel loaded with ZnO for wound healing

Bacterial infection and severe wound inflammation are two primary harmful problems that bring harm to the human body and may cause death when a large-scale skin defect occurs. Thus, developing an effective and quick wound healing strategy for curing skin damage and trauma is vital. This study has developed a multifunctional PLA/gelatin/ZnO nanofiber aerogel with a three-dimensional structure through electrospinning and freeze-drying technology for wound healing. It has validated that the nanofiber aerogel has an excellent antibacterial property and biocompatibility. Meanwhile, benefiting from its three-dimensional nanofiber structure, the PLA/gelatin/ZnO nanofiber aerogel possesses good water absorption and air permeability. In vivo experiments have determined that the PLA/gel/ZnO nanofiber aerogel scaffolds effectively promote skin infection's wound healing and enhance angiogenesis that is practical with increasing ZnO concentration.

Collagen in Wound Healing

Normal wound healing progresses through inflammatory, proliferative and remodeling phases in response to tissue injury. Collagen, a key component of the extracellular matrix, plays critical roles in the regulation of the phases of wound healing either in its native, fibrillar conformation or as soluble components in the wound milieu. Impairments in any of these phases stall the wound in a chronic, non-healing state that typically requires some form of intervention to guide the process back to completion. Key factors in the hostile environment of a chronic wound are persistent inflammation, increased destruction of ECM components caused by elevated metalloproteinases and other enzymes and improper activation of soluble mediators of the wound healing process. Collagen, being central in the regulation of several of these processes, has been utilized as an adjunct wound therapy to promote healing. In this work the significance of collagen in different biological processes relevant to wound healing are reviewed and a summary of the current literature on the use of collagen-based products in wound care is provided.