The effect of silicon groups on the physicochemical property and bioactivity of L-phenylalanine derived poly(amide-imide).

Poly(amide-imide) (PAI), serving as a synthetic polymer, has been widely used in industry for excellent mechanical properties, chemical resistance and high thermal stability. However, lack of suitable cell niche and biological activity limited the further application of PAI in biomedical engineering. Herein, silicon modified L-phenylalanine derived poly(amide-imide) (PAIS) was synthesized by introducing silica to L-phenylalanine derived PAI to improve physicochemical and biological performances. The influence of silicon amount on physicochemical, immune, and angiogenic performances of PAIS were systemically studied. The results show that PAIS exerts excellent hydrophilic, mechanical, biological activity. PAIS shows no effects on the number of macrophages, but can regulate macrophage polarization and angiogenesis in a dose-dependent manner. This study advanced our understanding of silicon modification in PAI can modulate cell responses via initiating silicon concentration regulation. The acquired knowledge will provide a new strategy to design and optimize biomedical PAI in the future.

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.