Hybrid gelatin-sulfated alginate scaffolds as dermal substitutes can dramatically accelerate healing of full-thickness diabetic wounds.

Diabetic foot ulcers (DFUs) are defined as chronic and non-healing wounds that cause skin disorders. Here, we introduce a novel biodegradable gelatin/sulfated alginate hybrid scaffold as a dermal substitute to accelerate the healing of full-thickness diabetic ulcers in a diabetic mouse model. The hybrid scaffold possessing different weight ratios of sulfated alginate, from 10 % up to 50 %, were prepared through chemical crosslinking by carbodiimide chemistry and further freeze-drying. Based on the in vitro cytotoxicity experiments, the hybrid scaffolds not only showed no cytotoxicity, but the cell growth also dramatically increased by increasing the sulfated alginate content. Finally, the pathology of hybrid scaffolds as the dermal substitutes for healing of full-thickness diabetic wounds showed the more appropriate formation of epidermal layer, more homogeneous distribution of collagenous tissue and lower penetration of immune cells for the hybrid scaffolds-treated wounds.

Improving anti-hemolytic, antibacterial and wound healing properties of alginate fibrous wound dressings by exchanging counter-cation for infected full-thickness skin wounds.

Nowadays, considerable effort is made to overcome bacterial diseases and combat bacterial resistance. In this context, development of safe and efficient antimicrobial wound dressings which can selectively fight against the bacteria and decrease disruption of normal cells such as red blood cells in wound bed is highly required. In this study, a series of ammonium salts of alginate were prepared and the role of different counter-cations including sodium, triethylammonium, tributylammonium and dihexylammonium were examined with respect to antimicrobial efficacy and selectivity as well as fibroblasts viability. We found that many different parameters such as hydrophilicity, linearity and branching structure, molecular weight and charge density can influence the selectivity of ammonium counter-cations. In vitro biological studies showed that tributylammonium alginate (TBA-Alg) possesses optimum anti-hemolytic and antibacterial properties with less cytotoxicity at 1 mg mL-1 compared with other counter-cations. Furthermore, the fibrous mat of TBA-Alg demonstrated higher swelling ratio and better anti-hemolytic and cytotoxic activities against fibroblasts compared to a commercial silver-impregnated calcium alginate wound dressing. Moreover, histopathological analysis of tributylammonium alginate fibrous mat revealed that this dressing accelerates reepithelialization of infected full-thickness skin wounds as well as the commercial silver-impregnated calcium alginate wound dressing.

Assessment of the Efficacy of Tributylammonium Alginate Surface-Modified Polyurethane as an Antibacterial Elastomeric Wound Dressing for both Noninfected and Infected Full-Thickness Wounds.

Risk factors of nonhealing wounds include persistent bacterial infections and rapid onset of dehydration; therefore, wound dressings should be used to accelerate the healing process by helping to disinfect the wound bed and provide moisture. Herein, we introduce a transparent tributylammonium alginate surface-modified cationic polyurethane (CPU) wound dressing, which is appropriate for full-thickness wounds. We studied the physicochemical properties of the dressing using Fourier transform infrared, 1H NMR, and 13C NMR spectroscopies and scanning electron microscopy, energy-dispersive X-ray, and thermomechanical analyses. The surface-modified polyurethane demonstrated improved hydrophilicity and tensile Young's modulus that approximated natural skin, which was in the range of 1.5-3 MPa. Cell viability and in vitro wound closure, assessed by MTS and the scratch assay, confirmed that the dressing was cytocompatible and possessed fibroblast migratory-promoting activity. The surface-modified CPU had up to 100% antibacterial activity against Staphylococcus aureus and Escherichia coli as Gram-positive and Gram-negative bacteria, respectively. In vivo assessments of both noninfected and infected wounds revealed that the surface-modified CPU dressing resulted in a faster healing rate because it reduced the persistent inflammatory phase, enhanced collagen deposition, and improved the formation of mature blood vessels when compared with CPU and commercial Tegaderm wound dressing.