Silicon-zinc-glycerol hydrogel, a potential immunotropic agent for topical application

Immunomodulatory zinc-based materials for tissue regeneration

Zinc(Zn)-based materials have contributed greatly to the rapid advancements in tissue engineering. The qualities they possess that make them so beneficial include their excellent biodegradability, biocompatibility, anti-bacterial activity, among and several others. Biomedical materials that act as a foreign body, will inevitably cause host immune response when introduced to the human body. As the osteoimmunology develops, the immunomodulatory characteristics of biomaterials have become an appealing concept to improve implant-tissue interaction and tissue restoration. Recently, Zn-based materials have also displayed immunomodulatory functions, especially macrophage polarization states. It can promote the transformation of M1 macrophages into M2 macrophages to enhance the tissue regeneration and reconstruction. This review covers mainly Zn-based materials and their characteristics, including metallic Zn alloys and Zn ceramics. We highlight the current advancements in the type of immune responses, as well as the mechanisms, that are induced by Zn-based biomaterials, most importantly the regulation of innate immunity and the mechanism of promoting tissue regeneration. To this end, we discuss their applications in biomedicine, and conclude with an outlook on future research challenges.

Individual iron(iii) glycerolate: synthesis and characterisation

Iron(ii) and iron(iii) salts of strong acids form iron glycerolates on heating at 180 °C with glycerol in the presence of an equivalent amount of alkali. Individual iron(iii) glycerolate was obtained for the first time. When Fe₃O₄ magnetic nanoparticles were heated with glycerol, an iron(iii) glycerolate shell was formed on their surface.

Individual iron(iii) glycerolate was obtained and characterized; a method for the preparation of an iron(iii) glycerolate shell on the surface of Fe₃O₄ MNPs was proposed.

Integrating silicon/zinc dual elements with PLGA microspheres in calcium phosphate cement scaffolds synergistically enhances bone regeneration

Integrating multiple pro-osteogenic factors into bone graft substitutes is a practical and effective approach to improve bone repair efficacy. Here, Si-Zn dual elements and PLGA microspheres were incorporated into calcium phosphate cement (CPC) scaffolds (PLGA/CPC-Si/Zn) as a novel strategy to synergistically enhance bone regeneration. The incorporation of PLGA microspheres and Si/Zn dual elements within CPC scaffolds improved the setting time, injectability and compressive strength. The PLGA/CPC-Si/Zn scaffolds displayed controlled sequential release of Si and Zn ions. In vitro, RAW 264.7 cells displayed the M2 phenotype with a high level of anti-inflammatory cytokines in response to PLGA/CPC-Si/Zn. The conditioned medium of RAW 264.7 cells cultured on the PLGA/CPC-Si/Zn scaffolds significantly enhanced the osteogenic differentiation of rat BMSCs. In a rat femur defect model, the implanted PLGA/CPC-Si/Zn scaffolds led to obvious new bone formation after 4 weeks, apparent bone ingrowth into the PLGA microspheres after 12 weeks, and was almost completely filled with mature new bone upon degradation of the PLGA microspheres at 24 weeks. These findings demonstrate that the PLGA/CPC-Si/Zn scaffolds promote osteogenesis by synergistically improving the immune microenvironment and biodegradability. Hence, integrating multiple trace elements together with degradable components within bone graft biomaterials can be an effective strategy for promoting bone regeneration.