Lipid nanoparticle-assisted miR29a delivery based on core-shell nanofibers improves tendon healing by cross-regulation of the immune response and matrix remodeling.

Inferior healing and peritendinous adhesions are the major clinical problems following Achilles tendon injury, leading to impaired motor function and an increased risk of re-rupture. These complications are presumed to be inextricably linked to inflammation and fibroscar formation. Here, microRNA29a is identified as a promising therapeutic target for tendon injury through the cross-regulation of the immune response and matrix remodeling. MiR29a-LNPs were successfully prepared by microfluidic technology. They are then loaded into the core-shell nanofibers to achieve local delivery in the injured tendon, where the shell layer is composed of PELA for anti-adhesion. Our studies reveal that miR29a regulates collagen synthesis and NF-κB activation in tenocytes, and promotes macrophage polarization by inhibiting the inflammasome pathway. In vivo studies of the Achilles tendon-rupture model indicate the best repair in the miR29a group, as evidenced by superior collagen composition and alignment, higher mechanical strength, and better functional recovery. In conclusion, a functionalized anti-adhesive membrane that promotes nascent tendon matrix remodeling and improves the regenerative immune microenvironment is developed for the treatment of tendon injury.