Impaired wound healing is a major medical problem in diabetes. The objective of this study was to determine the possible application of an insoluble fraction of fur-derived keratin biomaterial as a wound dressing in a full thickness surgical skin wound model in mice (n = 20) with iatrogenically induced diabetes. The obtained keratin dressing was examined in vitro and in vivo. In vitro study showed the keratin dressing is tissue biocompatible and non-toxic for murine fibroblasts. Antimicrobial examination revealed the keratin dressing inhibited the growth of S. aureus and E. coli. In vivo studies showed the obtained dressing significantly (p < 0.05) accelerated healing during the first week after surgery compared to control wounds. Keratin dressings were incorporated naturally into granulation and regenerating tissue without any visible signs of inflammatory response, which was confirmed by clinical and histopathological analysis. It is one of the first studies to show application of insoluble keratin proteins and its properties as a wound dressing. The obtained keratin dressing accelerated wound healing in mice with iatrogenically induced diabetes. Therefore, it can be considered as a safe and efficient wound dressing. Although future studies are needed to explain the molecular mechanism behind fur-derived keratin effect during the multilayer wound healing process, our findings may open the way for a new class of insoluble fur keratin dressings in chronic difficult to heal wounds treatment.

A series of new peptide dendrimers with amphiphilic surface, designed around a dendronized ornithine (Orn) core were synthesized and characterized by ESI-MS, ¹H-, ¹³C- NMR, and CD spectrometry. An improved antimicrobial potency against S. aureus and E. coli was detected as a result of an increased charge, higher branching and variable lipophilicity of the residues located at the C-terminus. Minimal inhibitory concentration (MIC) values indicated that the selected dendrimers were not sensitive to the physiological concentration of Na⁺ and K⁺ ions (100 mM), but expressed reduced potency at 10 mM concentration of Mg²⁺ and Ca²⁺ ions. Circular dichroism (CD) curves measured under various conditions revealed structure and solvent-dependent curve evolution. ESI-MS studies of gas-phase interactions between selected dendrimers and both anionic (DMPG) and neutral (DMPC) phospholipids revealed the presence of variously charged dendrimer/phospholipid aggregates with 1:1 to 1:5 stoichiometry. The collision-induced fragmentation (CID) of the most abundant [dendrimer/phospholipid]²⁺ ions of the 1:1 stoichiometry demonstrated that the studied dendrimers formed stronger complexes with anionic DMPG. Both phospholipids have higher affinity towards dendrimers with a more compact structure. Higher differences in CID energy necessary for dissociation of 50% of the complex formed by dendrimers with DMPG vs. DMPC (DCID₅₀) correlate with a lower hemotoxicity. Mass spectrometry results suggest that for a particular group of compounds the DCID₅₀ might be one of the important factors explaining selectivity of antimicrobial peptides and their branched analogs targeting the bacterial membrane. Both circular dichroism and mass spectrometry studies demonstrated that dendrimers of N^α- and N^ε-series possess a different conformation in solution and different affinity to model phospholipids, what might influence their specific microbicidal mechanism.

Impaired wound healing is a major medical challenge, especially in diabetics. Over the centuries, the main goal of tissue engineering and regenerative medicine has been to invent biomaterials that accelerate the wound healing process. In this context, keratin-derived biomaterial is a promising candidate due to its biocompatibility and biodegradability. In this study, we evaluated an insoluble fraction of keratin containing casomorphin as a wound dressing in a full-thickness surgical skin wound model in mice (n = 20) with iatrogenically induced diabetes. Casomorphin, an opioid peptide with analgesic properties, was incorporated into keratin and shown to be slowly released from the dressing. An in vitro study showed that keratin-casomorphin dressing is biocompatible, non-toxic, and supports cell growth. In vivo experiments demonstrated that keratin-casomorphin dressing significantly (p < 0.05) accelerates the whole process of skin wound healing to the its final stage. Wounds covered with keratin-casomorphin dressing underwent reepithelization faster, ending up with a thicker epidermis than control wounds, as confirmed by histopathological and immunohistochemical examinations. This investigated dressing stimulated macrophages infiltration, which favors tissue remodeling and regeneration, unlike in the control wounds in which neutrophils predominated. Additionally, in dressed wounds, the number of microhemorrhages was significantly decreased (p < 0.05) as compared with control wounds. The dressing was naturally incorporated into regenerating tissue during the wound healing process. Applied keratin dressing favored reconstruction of more regular skin structure and assured better cosmetic outcome in terms of scar formation and appearance. Our results have shown that insoluble keratin wound dressing containing casomorphin supports skin wound healing in diabetic mice.