AL-209

Titanium (Ti) and Ti alloy are the most widely used implant metals, but the limited bioactivity hinders the further clinical application. Aiming to enhance their osteogenesis, dual biomimetic strategies were utilized to decorate the surface of Ti by topological and biochemical cues. Firstly, a series of concentric circles with TiO₂ nanotubes on Ti were fabricated by photolithography and anodic oxidation. Furthermore, hydrothermal deposition and vacuum adsorption were adopted to introduce CaP and then assemble natural product of salidroside (Sal) on TiO₂ nanotubes (Sal/CaP/BTNT). Sal/CaP/BTNT was not only bio-mimicked the features of Haversian osteon in size and composition, but also slowed the release of Sal simultaneously. This biomimetic Haversian osteon induced bone marrow mesenchymal stem cells (BMSCs) to grow along the concentric circles, and was involved in BMP, Wnt/β-catenin, Notch and mechanical signaling pathways. Particularly, the expressions of related genes were up-regulated nearly to 200 % in mechanical signaling pathway compared to that of pure BMSCs. Additional, Sal enhanced osteogenic differentiation of BMSCs via BMP signaling pathway. The dual biomimetic Haversian osteon could promote the proliferation, differentiation and mineralization of BMSCs compared to that of pure BMSCs. In vivo studies showed that the CaP/BTNT and Sal/CaP/BTNT both promoted more new-bone formation than that of the control groups, indicating of their accelerated osseointegration due to the dual biomimetic Haversian osteon. The dual biomimetic strategies endowed Ti the excellent osteogenesis, which provided a promising surface modification strategy of Ti and Ti alloy to accelerate osteogenesis in clinic.

Salidroside (SAL) is a glycoside compound with good biological activity, which has multi-target therapeutic potential for various disease. It can significantly regulate various receptors, inflammatory mediators and signaling pathways. However, due to the problems of low content of natural sources, difficulty in isolation and purification and poor bioavailability, SAL cannot be widely used in clinical treatment. This article reviews the chemical total synthesis methods and the typical pharmacological effects of SAL, mainly about anti-tumor, anti-hypoxia and anti-sepsis fields. In addition, this article focuses on summarizing the research progress on the structural modification of SAL. Summarized the structure-activity relationship of SAL and its derivatives. These contents can enhance scholars' understanding of the current research progress on SAL, overcome the limitations which SAL is faced, and provide constructive insights for further development of new drugs based on SAL.