Improved functional recovery of rat transected spinal cord by peptide-grafted PNIPAM based hydrogel.

Facilitating angiogenesis, reducing the formation of glial scar tissue, and the occurrence of a strong inflammatory response are of great importance for the repair of central nerve damage. In our previous study, a temperature-sensitive hydrogel grafted with bioactive isoleucine-lysine-valine-alanine-valine (IKVAV) peptide was prepared and it showed regular three-dimensional porous structure, rapid (de)swelling performance and good biological activity. Therefore, in this study, we used this hydrogel scaffold to treat for SCI to study the effect of it to facilitate angiogenesis, inhibit the differentiation and adhesion of keratinocytes, and further reduce the formation of glial scar tissue. The results reveal that the peptide hydrogel scaffold achieved excellent performance and can also promote the expression of angiogenic factors and reduce the secretion of pro-inflammatory factors to a certain extent. Particularly, it can also inhibit the formation of glial scar tissue and repair damaged tissue. The proposed strategy for developing this hydrogel scaffold provides a new insight into designing biomaterials for a broad range of applications in the tissue engineering of the central nervous system (CNS).

Citrate regulates extracellular matrix mineralization during osteoblast differentiation in vitro.

The extremely high levels of citrate in bone highlight its important role, which must be involved in some essential functional or structural role that is required for the development and maintenance of normal bone. However, biomineralization researches have emphasized the interaction between the citrate and inorganic minerals during crystallization in cell-free systems. It is difficult to obtain a thorough and comprehensive understanding from cell-free experimental conditions and treatment methods. In this study, by proposing an osteoblast mineralization experimental model, we explored the regulation of citrate on bone apatite crystal structure. Our studies show that citrate stabilizes two precursors and then inhibits their transformation into hydroxyapatite. Concomitantly, the smaller size and lower crystallinity mineral deposition emerge during citrate-mediated osteogenic mineralization. These findings may provide a new perspective for the mechanism of osteogenic mineralization and a basis for further understanding of bone metabolism.

Enhanced proliferation and differentiation of neural stem cells by peptide-containing temperature-sensitive hydrogel scaffold.

Hydrogel has attracted great attention in the past few years as a widely used material for repairing central nerve damage. However, conventional hydrogel bio-scaffold, such as chitosan, gelatin, and sodium alginate, lack sufficient biological activity and have limited nerve repair capabilities. Therefore, to explore biologically active and intelligent hydrogel materials is particularly important and necessary for central nerve repair. Herein, we developed a temperature-sensitive hydrogel grafted with a bioactive peptide IKVAV (Ile-Lys-Val-Ala-Val, IKVAV). The hydrogel was prepared by copolymerization of N-propan-2-ylprop-2-enamide (NIPAM) and AC-PEG-IKVAV copolymers via reversible addition-fracture chain transfer (RAFT) polymerization, using polyethylene glycol (PEGDA) and N, N'-Methylenebisacrylamide (BISAM) as cross-linking agents. The prepared hydrogel scaffold demonstrates a series of excellent properties such as rapid (de)swelling performance, good biocompatibility, regular three-dimensional porous structure, and in particular good biological activity, which can guide cell fate and mediate neuron's differentiation. Therefore, the developed peptide hydrogel scaffold provides a new strategy for designing biomaterials that are widely used in tissue engineering for central nervous system injury.

Magnesium Calcium Phosphate Cement Incorporating Citrate for Vascularized Bone Regeneration.

The development of bioactive bone cement is still a challenge for vascularized bone regeneration. Citrate participated in multiple biological processes, such as energy metabolism, osteogenesis, and angiogenesis. However, it is difficult to obtain a thorough and comprehensive understanding on osteogenic effects of exogenous citrate from different experimental conditions and treatment methods. In this study, by using a magnesium calcium phosphate cement (MCPC) matrix, we investigated the dual effect of exogenous citrate on osteogenesis and angiogenesis. Our studies show that citrate elevates the osteogenic function of osteoblasts under low doses and the angiogenic function of vascular endothelial cells under a broader dose range. These findings furnish a new strategy for regulating angiogenesis and osteogenic differentiation by administration of citrate in MCPC, driving the development of bioactive bone repair materials.