Biodegradable cryogel wound dressing which can stop deep noncompressible hemorrhage and simultaneously promote wound healing is a highly promising biomaterial in clinics. Here, we prepared a series of biodegradable interpenetrating polymer network (IPN) dry cryogel hemostats by cryopolymerization of gelatin and dopamine. The IPN structure of cross-linked gelatin and polydopamine endows the cryogels good injectability, robust mechanical property, and shape memory property. The cryogels showed better whole bloodclotting capacity and more blood cell and platelet adhesion and activation than gauze and gelatin hemostatic sponge. The cryogels present less blood loss and shorter hemostasis time than gauze and gelatin hemostatic sponges in the mouse liver trauma model, rat liver incision model, and rabbit liver cross incision model. Especially, the hemostatic effect of the cryogel on deep narrow noncompressible hemorrhage was determined by the rabbit liver defect deep narrow noncompressible hemorrhage model. The cryogel rapidly stopped deep massive noncompressible hemorrhage in the swine subclavian artery and vein complete transection model. Besides, the component of polydopamine endows cryogels with excellent antioxidant activity and NIR irradiationassisted photothermal antibacterial ability. Gelatin/dopamine cryogels were more effective in promoting wound healing than Tegaderm films. The developed biodegradable cryogels with a simple preparation process and low cost and which can be easily carried and used present huge potential as novel wound dressing for rapid hemostasis and promoting wound healing.

No abstract

Poor healing response after rotator cuff reconstruction is multifactorial, with the inflammatory microenvironment and deficiency of stem cell differentiation factors at the lesion site being most relevant. However, there is a lack of effective tissue engineering strategies that can simultaneously exert anti-inflammatory and pro-differentiation effects to promote rotator cuff healing. Methods: In this study, we synthesized and characterized a novel active drug delivery vector that successfully overcame the challenge of simultaneous high-efficiency loading and controlled release of Mg 2+ and curcumin. The anti-inflammatory and pro-differentiation effects of the composite hydrogel were evaluated in vitro and in vivo . Moreover, healing of the rotator cuff tendon-to-bone interface was studied by histology, immunofluorescence, and biomechanical tests. Results: The composite hydrogel exhibited excellent biocompatibility and injectability, good adhesiveness, and rapid self-healing. The released curcumin showed obvious anti-inflammatory and antioxidation effects, which protected stem cells and tendon matrix. Furthermore, released Mg 2+ promoted stem cell aggregation and chondrogenesis. Moreover, biomechanical tests and histological results of a rat rotator cuff tear model at 8 weeks after surgery indicated that the composite hydrogel significantly enhanced tendon-to-bone healing. Conclusions: The composite hydrogel mediated sustained in situ release of curcumin and Mg 2+ to effectively promote rotator cuff tendon-to-bone healing via anti-inflammatory and pro-differentiation effects. Therefore, this composite hydrogel offers significant promise for rotator cuff repair.

No abstract

Preparing a micropatterned elastomer film with characteristics that can simulate the mechanical properties, anisotropy, and electroactivity of natural myocardial tissues is crucial in cardiac tissue engineering after myocardial infarction (MI). Therefore, in this study, we developed several elastomeric films with a surface micropattern based on poly (glycerol sebacate) (PGS) and graphene (Gr). These films have sufficient mechanical strength (0.6 ± 0.1–3.2 ± 0.08 MPa) to withstand heartbeats, and the micropatterned structure also satisfies the natural myocardium anisotropy in the transverse and vertical. Moreover, Gr makes these films conductive (up to 5.80 × 10−7 S/m), which is necessary for the conduction of electrical signals between cardiomyocytes and the cardiac tissue. Furthermore, they have good cytocompatibility and can promote cell proliferation in H9c2 rat cardiomyocyte cell lines. In vivo test results indicate that these films have good biocompatibility. Notably, a film with 1 wt% Gr content (PGS–Gr1) significantly affects the recovery of myocardial function in rats after MI. This film effectively decreased the infarct size and degree of myocardial fibrosis and reduced collagen deposition. Echocardiographic evaluation showed that after treatment with this film, the left ventricular internal dimension in systole and left ventricular internal dimension in diastole of rats exhibited a significant downward trend, whereas the fractional shortening and ejection fraction were significantly increased compared with the control group. These data indicate that this electroactive micropatterned anisotropic elastomer film can be applied in cardiac tissue engineering.