Development and characterization of an immunomodulatory and injectable system composed of collagen modified with trifunctional oligourethanes and silica

Nanomaterials-Functionalized Hydrogels for the Treatment of Cutaneous Wounds

Hydrogels have been utilized extensively in the field of cutaneous wound treatment. The introduction of nanomaterials (NMs), which are a big category of materials with diverse functionalities, can endow the hydrogels with additional and multiple functions to meet the demand for a comprehensive performance in wound dressings. Therefore, NMs-functionalized hydrogels (NMFHs) as wound dressings have drawn intensive attention recently. Herein, an overview of reports about NMFHs for the treatment of cutaneous wounds in the past five years is provided. Firstly, fabrication strategies, which are mainly divided into physical embedding and chemical synthesis of the NMFHs, are summarized and illustrated. Then, functions of the NMFHs brought by the NMs are reviewed, including hemostasis, antimicrobial activity, conductivity, regulation of reactive oxygen species (ROS) level, and stimulus responsiveness (pH responsiveness, photo-responsiveness, and magnetic responsiveness). Finally, current challenges and future perspectives in this field are discussed with the hope of inspiring additional ideas.

Decellularization of porcine esophageal tissue at three diameters and the bioscaffold modification with EETs-ECM gel

Damaged complex modular organs repair is a current clinical challenge in which one of the primary goals is to keep their biological response. An interesting case of study it is the porcine esophagus since it is a tubular muscular tissue selected as raw material for tissue engineering. The design of esophageal constructs can draw on properties of the processed homologous extracellular matrix (ECM). In this work, we report the decellularization of multilayered esophagus tissue from 1-, 21- and 45-days old piglets through the combination of reversible alkaline swelling and detergent perfusion. The bioscaffolds were characterized in terms of their residual composition and tensile mechanical properties. The biological response to esophageal submucosal derived bioscaffolds modified with ECM gel containing epoxyeicosatrienoic acids (EETs) was then evaluated. Results suggest that the composition (laminin, fibronectin, and sulphated glycosaminoglycans/sGAG) depends on the donor age: a better efficiency of the decellularization process combined with a higher retention of sGAG and fibronectin is observed in piglet esophageal scaffolds. The heterogeneity of this esophageal ECM is maintained, which implied the preservation of anisotropic tensile properties. Coating of bioscaffolds with ECM gel is suitable for carrying esophageal epithelial cells and EETs. Bioactivity of EETs-ECM gel modified esophageal submucosal bioscaffolds is observed to promote neovascularization and antiinflammatory after rabbit full-thickness esophageal defect replacement.

Gel dressing based on type I collagen modified with oligourethane and silica for skin wound healing

Cutaneous wound healing is a complex process that leads the skin reparation with the formation of scar tissue that typically lacks skin appendages. This fact drives us to find new strategies to improve regenerative healing of the skin. This study outlines, the contribution of colloidal silica particles and oligourethane crosslinking on the collagen material properties and the effect on skin wound healing in rats. We characterized the gel properties that are key forin-situgelation, which is accomplished by the latent reactivity of oligourethane bearing blocked isocyanate groups to crosslink collagen while entrapping silica particles. The swelling/degradation behavior and the elastic modulus of the composite gel were consistent with the modification of collagen type I with oligourethane and silica. On the other hand, these gels were characterized as scaffold for murine macrophages and human stem cells. The application of a composite gel dressing on cutaneous wounds showed a histological appearance of the recovered skin as intact skin; featured by the epidermis, hair follicles, sebaceous glands, subcutaneous adipose layer, and dermis. The results suggest that the collagen-based composite dressings are promising modulators in skin wound healing to achieve a regenerative skin closure with satisfactory functional and aesthetic scars.