Nanoconfinement of Ammonia Borane via Hybrid-Phased Titanate Nanocrystals Enables Sustained H₂ Release for Diabetic Bone Repair.

Abstract

Despite its potential in hydrogen (H₂) therapy, ammonia borane (AB) has limited biomedical applications due to its uncontrolled hydrolysis rate and potential to cause cytotoxicity. Existing material-based delivery strategies focus on accelerating AB hydrolysis for H₂ production, hence exacerbating these issues. A new nanoconfinement strategy is reported, which loads AB onto oxygen-deficient, hybrid-phased titanate nanocrystals on implant surfaces through a unique one-end-anchored docking (OEAD) mechanism. This nanoconfinement strategy effectively restricts the release of AB molecules, allowing only water molecules to infiltrate the interlayer space for slow hydrolysis and sustained H₂ release. This significantly prolongs the duration of H₂ release and effectively circumvents the cytotoxicity associated with AB interacting with hydrogen peroxide (H₂O₂) in the inflammatory microenvironment. In vitro and in vivo have shown that sustained H₂ release from the implant surface effectively alleviates diabetes-related oxidative stress, and combined with the release of magnesium ions (Mg²⁺) synergistically promotes innervated-vascularized bone regeneration.