Enhanced healing of a full-thickness wound by a thermoresponsive dressing utilized for simultaneous transfer and protection of adipose-derived mesenchymal stem cells sheet

Optimization and Characterization of a Novel Antioxidant Naringenin-Loaded Hydrogel for Encouraging Re-Epithelization in Chronic Diabetic Wounds: A Preclinical Study

Nonhealed wounds are one of the most dangerous side effects of type-2 diabetes, which is linked to a high frequency of bacterial infections around the globe that eventually results in amputation of limbs. The present investigation aimed to explore the drug-loaded (naringenin) hydrogel system for chronic wound healing. The hydrogel membranes comprising Na-alginate with F-127 and poly(vinyl alcohol) were developed to treat chronic wounds using the quality-by-design (QbD) approach. The optimized formulation was tested for various parameters, such as swelling, gel fraction, water vapor transition rate (WVTR), etc. In vitro evaluation indicated that a drug-loaded hydrogel displayed better tissue adhesiveness and can release drugs for a prolonged duration of 12 h. Scratch assay performed on L929 cell lines demonstrated good cell migration. The diabetic wound healing potential of the hydrogel membrane was assessed in streptozotocin-induced male Wistar rats (50 mg/kg). Higher rates of wound closure, re-epithelialization, and accumulation of collagen were seen in in vivo experiments. Histopathologic investigation correspondingly implied that the drug-loaded hydrogel could enhance dermal wound repair. The improved antimicrobial and antioxidant properties with expedited healing indicated that the drug-loaded hydrogel is a perfect dressing for chronic wounds.

Fabrication and characterization of bilayer scaffolds made of decellularized dermis/nanofibrous collagen for healing of full-thickness wounds

Skin tissue engineering has progressed from simple wound dressings to biocompatible materials with desired physico-chemical properties that can deliver regenerative biomolecules. This study describes using a novel biomimetic hybrid scaffold of decellularized dermis/collagen fibers that can continuously deliver stromal cell-derived factor-1 alpha (SDF-1α) for skin regeneration. In diabetic rat models, the idea that sustained SDF-1α infusion could increase the recruitment of CXCR4-positive cells at the injury site and improve wound regeneration was investigated. The morphology of the scaffold, its biocompatibility, and the kinetics of SDF-1 release were all assessed. SDF-1α was successfully incorporated into collagen nanofibers, resulting in a 200-h continuous release profile. The microscopic observations exhibited that cells are attached and proliferated on proposed scaffolds. As evaluated by in vivo study and histological examination, fabricated scaffold with SDF-1α release capacity exhibited a remarkably more robust ability to accelerate wound regeneration than the control group. Besides, the SDF-1α-loaded scaffold demonstrated functional effects on the proliferation and recruitment of CD31 and CXCR4-positive cells in the wound bed. Additionally, no adverse effects such as hyperplasia or scarring were found during the treatment period. It may be concluded that the fabricated hybrid scaffold based on natural polymer opens up a new option for topical administration of bioactive molecules. We believe the SDF-1α-loaded hybrid scaffold has promise for skin tissue engineering.

Preparation and evaluation of antibacterial wound dressing based on vancomycin-loaded silk/dialdehyde starch nanoparticles

One of the main reasons infected wounds go untreated is that antibiotic-resistant bacteria mainly cause infection. Vancomycin is an antibiotic used against Gram-positive bacteria, such as MRSA, but it has limited intravenous use due to its toxicity. This study describes using a local drug delivery approach at the wound site. The aim is to prepare a silk dressing containing dialdehyde starch nanoparticles loaded with vancomycin that can cure infection through the controlled release of antibiotics. First, the starch was oxidized by sodium periodate solution and converted to dialdehyde starch. Dialdehyde starch was converted into nanoparticles by the microemulsion method. Simultaneously, with nanoparticle formation, the antibiotic vancomycin (VAN), added to the solution, was loaded into the dialdehyde starch nanoparticles (DASNP). The wound dressing (SF/DASNP/VAN) was prepared by adding nanoparticles containing antibiotics to the silk fibroin (SF) solution, and then, the solution containing the nanoparticles was freeze-dried, and the nanoparticles were placed inside the silk matrix. Drug release of dressings was performed by immersion in phosphate-buffered saline, and cytotoxicity by MTT assay and antibacterial properties of dressings were investigated by the inhibition zone method. The morphology of the SF/DASNP/VAN dressing, its biocompatibility, antibacterial efficiency, and antibiotic release kinetics were assessed. The synthesized dressing has the desired biocompatibility with 69% cell viability and shows antibacterial properties against MRSA with a growth inhibition zone diameter of 12 mm. Also, VAN was successfully incorporated into the dressing, resulting in a 144-h continuous release profile. It may be concluded that the fabricated dressing based on silk and dialdehyde starch nanoparticles opens up a new option for topical administration of antibiotics. We believe its properties can be considered a new dressing for infectious wounds by reducing infection associated with controlled drug delivery.

Microorganism-derived biological macromolecules for tissue engineering

According to literature, certain microorganism productions mediate biological effects. However, their beneficial characteristics remain unclear. Nowadays, scientists concentrate on obtaining natural materials from live creatures as new sources to produce innovative smart biomaterials for increasing tissue reconstruction in tissue engineering and regenerative medicine. The present review aims to introduce microorganism-derived biological macromolecules, such as pullulan, alginate, dextran, curdlan, and hyaluronic acid, and their available sources for tissue engineering. Growing evidence indicates that these materials can be used as biological material in scaffolds to enhance regeneration in damaged tissues and contribute to cosmetic and dermatological applications. These natural-based materials are attractive in pharmaceutical, regenerative medicine, and biomedical applications. This study provides a detailed overview of natural-based biomaterials, their chemical and physical properties, and new directions for future research and therapeutic applications.

Antibacterial and Biocompatible Hydrogel Dressing Based on Gelatin- and Castor-Oil-Derived Biocidal Agent

Favored antibacterial activity associated with excellent biocompatibility, mechanical durability, and exudate handling needs to be addressed by modern dressing to achieve the desired wound healing. This paper deals with developing a new green and facile approach to manufacturing nonleachable antibacterial gelatin-based films for wound dressing. Therefore, a reactive methoxy-silane-functionalized quaternary ammonium compound bearing a fatty amide residue originating from castor oil (Si-CAQ) was initially synthesized. The antibacterial dressings were then fabricated via sol-gel and condensation reactions of the mixture containing gelatin, Si-CAQ, (3-glycidyloxypropyl) trimethoxysilane, and poly(vinyl alcohol). By utilizing bioactive polymers as starting materials and eliminating organic solvents during the dressing preparation, desirable clinical safety could be ensured. The gelatin-based films presented appropriate mechanical properties, such as flexibility and strength, in both dried and hydrated states (tensile strength >6 MPa and elongation >100). It is due to the in situ generations of the inorganic silicon domain in the organic framework via the sol-gel cross-linking process. The prepared dressings exhibited desirable features, including excellent biocompatibility (cell viability >95%), proper wound-exudate-managing characteristics (equilibrium water contact (EWA) 280-350% and water vapor transmission rate (WVTR) 2040-2200 g/m²/day), fluid handling capacity (FHC) (3-3.35 g), as well as commendable hemocompatibility. The promising bactericidal activity of the dressing against Bacillus subtilis, methicillin-resistant Staphylococcus aureus, and Escherichia coli strains with a contact-killing efficacy of 100% could prevent infection development at the wounded area. As evaluated by the wound scratch assay, the desired fibroblast cell growth, migration, and proliferation indicated the capability of the dressing to facilitate the healing process by encouraging fibroblast cell migration to the damaged area. In vivo wound-healing results showed that the prepared biocidal dressing stimulates wound healing and enhances epithelialization, collagen maturation, and vascularization of wounds due to their antibacterial effects and accelerated cellular functions.