FIGURE 1.

Preparation of MB(SDF‐1α) and OA animal model. A, Flow chart of chemotaxis microbubble MB(SDF‐1α) preparation. The carboxyl group carried by the lipid molecule and the amino group of SDF‐1 are linked by a covalent bond. After all, chemotactic microbubbles containing C3F8 and SDF‐1α linked in the outer shell were prepared. B, The modified Hulth's modelling method for OA. During the operation, the medial meniscus is removed, and the anterior cruciate ligament is severed, causing joint instability and eventually osteoarthritis. An OA model was established on bilateral knees