Articular cartilage lacks self-repair capabilities, and its injuries can affect the subchondral bone. The integrated repair of bone and cartilage is an urgent global challenge that needs to be addressed. Clinical methods such as microfracture, autologous and allogeneic osteochondral transplantation have issues including incomplete filling, limited sources, immune rejection, and the formation of fibrocartilage. Currently, the use of tissue engineering technology is a hot topic in international research. An ideal implant should provide both the mechanical strength and microenvironment suitable for cartilage and subchondral bone, match the anatomical site morphology, be controllable in degradation, and achieve integrated reconstruction of the cartilage-bone interface and concurrent regeneration. Due to its excellent biosecurity, mechanical properties, degradability, and the ability to promote osteogenic and chondrogenic activity, the construction of a biomimetic biphasic scaffold with a magnesium alloy as the matrix has shown feasibility and potential superiority.
The research objective of the project is to leverage China's solid preliminary research foundation in the field of biomedical magnesium alloys and its comparative advantages internationally. Through "innovation in material and structural design, preparation process, and endogenous regeneration mechanism," the project aims to develop a 3D printed magnesium alloy porous scaffold with a hydrogel/ceramic biphasic active interface. This will construct a "structure-function" integrated biomimetic fully degradable scaffold for osteochondral repair. The safety, effectiveness, and superiority will be verified through in vitro and in vivo experiments, and the matching relationship between scaffold degradation and tissue reconstruction, as well as the key physicochemical factors and mechanisms of endogenous induction of tissue regeneration, will be elucidated.
To achieve the above objectives, the project mainly sets three research contents: 1) The design and preparation of the 3D printed magnesium alloy porous scaffold matrix; 2) The study of the biomimetic biphasic active interface on the magnesium alloy scaffold; 3) The study of the promotion of osteochondral regeneration and mechanisms of the magnesium alloy composite biphasic scaffold in vitro and in vivo. The key technical issues to be solved include: "The 3D printing preparation of the scaffold with controllable mechanical properties and structure, the controllable degradation and biocompatibility of the magnesium alloy scaffold matrix," and "The biological function adaptation of the biphasic interface that mimics the structure of cartilage and subchondral bone." The important scientific issues to be addressed are: to elucidate the cellular and molecular mechanisms by which key physicochemical factors such as scaffold pore structure, magnesium degradation products, and biphasic biomimetic interface induce cartilage and bone regeneration.
