TPMS-Gyroid Scaffold-Mediated Up-Regulation of ITGB1 for Enhanced Cell Adhesion and Immune-Modulatory Osteogenesis.

Abstract

The porous structure is crucial in bone tissue engineering for promoting osseointegration. Among various structures, triply periodic minimal surfaces (TPMS) -Gyroid has been extensively studied due to its superior mechanical and biological properties. However, previous studies have given limited attention to the impact of unit cell size on the biological performance of scaffolds. In this research, four TPMS-Gyroid titanium scaffolds with different unit cell sizes (TG15, TG20, TG25, and TG30) are fabricated using Selective Laser Melting (SLM) to explore their effects on osseointegration. Mechanical tests revealed that TG15 and TG20 exhibited superior compressive strength. In vitro experiments demonstrated that TG20 facilitated better cell adhesion through robust integrin protein expression initially, which subsequently enhanced cell proliferation and osteogenic differentiation. Furthermore, macrophages on TG20 showed higher Integrin β1 (ITGB1) expression, promoting their polarization to the M2 phenotype, which suppressed inflammation, fostered bone integration, and angiogenesis. In vivo studies confirmed TG20's effectiveness in promoting bone ingrowth by reducing inflammation. This study highlights TG20's structural advantages, making it a promising bone scaffold with exceptional osteogenic and angiogenic properties through osteoimmune microenvironment modulation. Therefore, TG20 holds significant potential for applications in bone tissue engineering.