Bone marrow-derived mesenchymal stem cells laden novel thermo-sensitive hydrogel for the management of severe skin wound healing.

Bone marrow-derived mesenchymal stem cells (BMSCs) are easy to collect and culture, and it is identified that it has multi-directional differentiation potential, moreover it has low immunogenicity, hence it can be used as an allogeneic cell source for skin wound healing. Hydrogel has been widely used in skin wound healing own to it is able to mimic the 3D microenvironment of cells, which supports cell proliferation, migration and secretion. In this study, we created a novel biocompatible thermo-sensitive hydrogel to carry BMSCs for full-thickness skin wound healing. The thermo-sensitive hydrogel loaded with BMSCs can fast achieve sol-gel transition after implanting to the wound. Histological results confirmed that hydrogel-BMSCs combination group showed significant promotion of wound closure, epithelial cells' proliferation and re-epithelialization, and reduced inflammatory responses in the wounds and in the tissues surrounding the wounds. The combination therapy also can promote collagen deposition, TGF-ß1 and bFGF secretion and tissue remodeling. The present study provides a promising strategy for the clinical treatment of skin wounds.

Hydrogen bonds autonomously powered gelatin methacrylate hydrogels with super-elasticity, self-heal and underwater self-adhesion for sutureless skin and stomach surgery and E-skin.

Interface-interaction induced self-healing and self-adhesive are a gem-like attribute inspired by our Mother Nature. Biocompatible gelatin methacrylate (GelMA) hydrogels exhibit tunable mechanical properties which are favorable in biomedical applications. However, it is difficult to integrate high stiffness, super-elasticity, large deformability and self-healing property together. Here, we report a GelMA-based double-network (DN) hydrogel with above properties by utilizing tannic acid (TA) as a multi-functional H-bond provider. We first investigated the morphological and mechanical properties' changes of GelMA over different TA's concentrations and treating times. In comparison to pristine GelMA hydrogel (10% w/v), the GelMA-TA hydrogels presented significant increase in ultimate stress (4.3-fold), compressive modulus (2.5-fold), and especially in elongation (6-fold). Adhesion properties of GelMA-TA can be tuned by TA and have been proven to be water-resistant. To test gels' feasibility in vivo, we applied GelMA-TA gels to close skin wound and gastric incision without suture. The results indicated the gels had the capabilities of promoting wound healing with superior tissue restoration and minimal tissue adhesion. Furthermore, integrated with carbon nanotubes, the GelMA-TA-carbon nanotube gel was an alternative self-healing electric skin with strain-sensitive conductivity. This work demonstrated a strategy to yield mechanically strong hydrogel adhesives for innovative biomedical applications.

Egg Albumen as a Fast and Strong Medical Adhesive Glue.

Sutures penetrate tissues to close wounds. This process leads to inflammatory responses, prolongs healing time, and increases operation complexity. It becomes even worse when sutures are applied to stress-sensitive and fragile tissues. By bonding tissues via forming covalent bonds, some medical adhesives are not convenient to be used by surgeons and have side effects to the tissues. Here egg albumen adhesive (EAA) is reported with ultrahigh adhesive strength to bond various types of materials and can be easily used without any chemical and physical modifications. Compared with several commercial medical glues, EAA exhibits stronger adhesive property on porcine skin, glass, polydimethylsiloxane. The EAA also shows exceptional underwater adhesive strength. Finally, wound closure using EAA on poly(caprolactone) nanofibrous sheet and general sutures is investigated and compared in a rat wound model. EAA also does not show strong long-term inflammatory response, suggesting that EAA has potential as a medical glue, considering its abundant source, simple fabrication process, inherent nontoxicity, and low cost.

Flexible and highly interconnected, multi-scale patterned chitosan porous membrane produced in situ from mussel shell to accelerate wound healing.

Utilization of the underlying mechanisms of biological systems is the principal endeavor of biomimetics, the primary goal of which is to treat on-going biological processes. From the perspective of tissue engineering, one purpose of biomimetics is to create highly cellular- or tissue-favored environments for bio-defect repair. Marine creatures such as mussels have inspired bioengineers to design ideal cellular substrates, strong adhesives, and other bioengineering materials. Herein, we report a novel mussel shell-derived membrane for wound dressing. Mussel shell in situ manufactured a highly flexible membrane with a regular porous pattern after the direct action of acid (A-shell) followed by base treatment (B-shell). The SEM images display elegantly patterned polygons with nanowalls (about 710 nm). Compared with the A-shell, the B-shell has a more defined and flexible structure. FTIR characterization of the structures indicates that deacetylation occurred on the B-shell. A cellular toxicity study was conducted to determine the optimized processing parameters before applying the wound healing model. The B-shell significantly closed the wound at an early stage (day 10) followed by complete contraction at a later stage (day 21). This is completely consistent with the higher level of α-SMA protein, which accelerates wound contraction in the wound sites. As a key index of the integration between host and guest, a high blood vessel density was detected in both the A-shell and B-shell groups. The treated shells can improve epidermal migration, the formation of granulation tissue, neovascularization and hair follicles, and reduce scar tissue. Our mussel shell-derived membrane could have potential as a wound dressing and other biomedical uses.