Chitosan Hydrogel Dressing Loaded with Adipose Mesenchymal Stem Cell-Derived Exosomes Promotes Skin Full-Thickness Wound Repair.

Cutaneous trauma repair is still a challenge in the clinic due to the scar formation and slow healing rate, especially for diabetic patients. Various drug-loading wound dressings have been explored to solve this problem. Mesenchymal stem cell (MSC)-derived exosomes have been considered as a potential cell-free drug because of their anti-inflammation function and tissue repair property that are comparable to that of MSCs. Herein, a composite wound dressing (Exo/Gel) consisting of the chitosan hydrogel and adipose MSC-derived exosome (ADMSC-Exo) was designed and fabricated by a physical mixing method to promote the skin full-thickness wound repair. The exosomes were slowly released from the Exo/Gel dressing with the degradation of the chitosan hydrogel. The Exo/Gel displayed enhanced cell migration and angiogenic properties in vitro. And the results in the rat skin wound model showed that the Exo/Gel could promote the regular collagen deposition, angiogenesis, and hair follicle mosaicism regeneration. These results proved that the hydrogel dressing with ADMSCs-derived exosomes can accelerate skin wound healing, which is a strategy for developing wound dressings.

Removal of Pb(II) and phosphorus in water by γ-Al2O3/biochar.

In this work, we synthesized activated alumina biochar composites (γ-Al2O3/BC) by sol-gel method, which improved the problem that the surface charge of γ-Al2O3 was not conducive to the removal of heavy metal cation in a neutral solution, and then explored the feasibility of removing Pb(II) by γ-Al2O3/BC as well as reusing Pb-laden waste sludge to remove phosphorus (P) and its micro-adsorption mechanisms. The results show that the maximum adsorption capacity of γ-Al2O3/BC for Pb(II) is 182.48 mg/g, and the removing capacity of recycled Pb-laden slag for P also reaches 87.13 mg/g. It was found that the presence of Pb in the slag makes P removal more effective. In addition, in the process of P removal, the Pb in the slag will not be released, which will not cause secondary pollution to the water. The micro-adsorption mechanism of Pb(II) and P on the composites was investigated by XPS, XRD, and FTIR. It demonstrates that special functional groups such as hydroxy-aluminum, hydroxyl, and carboxyl groups can remove Pb(II) through strong surface complexation and electrostatic attraction. Furthermore, the removal mechanism of P from Pb-laden sludge includes chemisorption and complexation, and the precipitation of P and Pb on the adsorbent surface is the main reason for the removal of P. Therefore, it is feasible to further effectively remove P by using the waste biochar containing Pb. The idea of this paper provides a potential method for the reuse of waste adsorbent.

An injectable hydrogel scaffold with IL-1ß-activated MSC-derived exosomes for the treatment of endometritis.

Chronic endometritis is a common gynecological disease resulting from various long-term recurrent infections, and is closely related to myositis, miscarriage, and even infertility. There is still no satisfactory treatment method currently in clinical therapy. Mesenchymal stem cell (MSC)-derived exosomes, an important kind of paracrine product, have been used to treat inflammatory diseases due to their promising immunomodulatory function and tissue repair ability similar to MSCs. Considering that the exosome contents and functions are regulated by the MSC status and the MSC status is significantly influenced by its surrounding microenvironment, we propose a hypothesis that exosomes derived from inflammation-simulated MSCs will possess stronger inhibition ability for inflammation. Herein, we used IL-1ß to activate rat bone MSCs for obtaining ß-exo and constructed an injectable polypeptide hydrogel scaffold by loading ß-exo (ß-exo@pep) for an in situ slow release of ß-exo. The results showed that the polypeptide hydrogel can provide a sustained release of exosomes in 14 days. The ß-exo@pep composite hydrogel can more effectively inhibit the production of inflammatory factors such as TNF-α, IL-1ß, and IFN-γ, while it can promote the production of anti-inflammatory factors such as Arg-1, IL-6, and IL-10. The ß-exo@pep composite hydrogel significantly promoted cell migration, invasion, and vessel tube formation in vitro. The experiments in a rat model of endometritis proved that the ß-exo@pep composite scaffold possessed excellent ability towards anti-inflammation and endometrial regeneration. The research studies on the molecular mechanism revealed that the protein expressions of HMGB1 and phosphorylated IKB-α and p65 are down-regulated in the cells treated with ß-exo@pep, indicating the involvement of the NF-κB signaling pathway. This study provides an effective method for the treatment of chronic endometritis, which is promising for clinical use.