Sustained-Release RANKL Microneedles for Safe Orthodontic Acceleration

Area of Science:

• Biomaterials Science
• Orthodontics
• Drug Delivery Systems

Background:

• Prolonged orthodontic treatment poses risks, necessitating faster, safer methods.
• Microneedles (MNs) offer minimally invasive, localized drug delivery for improved patient outcomes.
• Controlled release of biomolecules is key to accelerating orthodontic tooth movement (OTM).

Purpose of the Study:

• To develop a microneedle (MN) patch for sustained, localized delivery of receptor activator of nuclear factor kappa-B ligand (RANKL).
• To evaluate the efficacy and safety of the RANKL-loaded MN patch in accelerating OTM and bone remodeling.
• To compare the MN delivery system with direct RANKL injection regarding tooth movement and root resorption.

Main Methods:

• Fabrication of a detachable MN patch integrating mesoporous silica nanoparticles (MSNs) within a supramolecular hydrogel for hierarchical RANKL release.
• In vitro assessment of MN biocompatibility, mechanical strength, and RANKL release kinetics and bioactivity.
• In vivo evaluation of the RANKL-loaded MN patch in a rat OTM model, assessing tooth movement, bone remodeling, and root resorption.

Main Results:

• The developed MSN@CMC-MPP⊂CB[8] MN patches showed good biocompatibility and mechanical properties for gingival penetration.
• In vitro studies confirmed sustained RANKL release from MSNs, preserving bioactivity for osteoclastogenesis.
• In vivo, RANKL-loaded MN patches accelerated OTM and bone remodeling, with significantly less root resorption than direct RANKL injection.

Conclusions:

• The hierarchical-release MN patch provides a safe and effective platform for localized, sustained RANKL delivery.
• This innovative microneedle technology significantly enhances orthodontic treatment efficiency while minimizing adverse effects like root resorption.
• The developed MN system represents a promising advancement for accelerating orthodontic tooth movement.