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

Abstract Despite its potential in hydrogen (H 2 ) 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 H 2 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 H 2 release. This significantly prolongs the duration of H 2 release and effectively circumvents the cytotoxicity associated with AB interacting with hydrogen peroxide (H 2 O 2 ) in the inflammatory microenvironment. In vitro and in vivo have shown that sustained H 2 release from the implant surface effectively alleviates diabetes‐related oxidative stress, and combined with the release of magnesium ions (Mg 2+ ) synergistically promotes innervated‐vascularized bone regeneration.