Development of a novel hyaluronic acid/alginate/RANKL degradable microneedle patch for accelerating bone remodeling and orthodontic tooth movement through promoting osteoclastogenesis

The prolonged duration of orthodontic treatment remains a significant concern for both orthodontists and patients. In this study, we developed a degradable microneedle (MN) patch composed of hyaluronic acid (HA) and sodium alginate (SA) for the delivery of receptor activator of nuclear factor-kappa B ligand (RANKL) to accelerate tooth movement. This MN patch that was crosslinked by calcium chloride (CaCl 2 ) exhibited adequate mechanical properties and favorable in vitro mucosal insertion ability. Moreover, the MN patch can achieve sustained release of RANKL and maintain the biological stability of RANKL protein after one month of storage at −20 °C, 4 °C, or 37 °C. In vitro experiments using RAW 264.7 cells indicated that the HA/SA/RANKL MN possessed excellent biocompatibility and could effectively induce osteoclast differentiation. In vivo application of the HA/SA/RANKL MN in rat models showed a remarkable effect in promoting osteoclast formation and accelerating tooth movement. These findings suggest that the degradable HA/SA/RANKL MN holds significant potential for enhancing tooth movement efficiency.