Antioxidant Zein/ACP/Epigallocatechin Gallate Composite Scaffold for Reactive Oxygen Species-Scavenging and Bidirectional Regulation of Bone Remodeling

Overcoming oxidative stress resulting from reactive oxygen species (ROS) overload in the microenvironment of bone injury is crucial for bone repair. This study developed a multifunctional composite scaffold composed of zein, adenosine-calcium phosphate (ACP), and epigallocatechin gallate (EGCG) for enhanced bone regeneration through antioxidant activity. For the preparation of the Zein/ACP/EGCG (Z/A/E) composite scaffold, ACP nanoparticles were first synthesized using an enzymatic reaction and characterized by SEM, EDS, FTIR, and XRD. ACP nanoparticles showed great biocompatibility and osteoinductivity within a certain dose range in vitro. A three-dimensional (3D) porous Zein/ACP (Z/A) composite scaffold was fabricated by compression molding and particulate leaching, followed by the adsorption of EGCG onto its surface. The final Z/A/E composite scaffold exhibited enhanced surface hydrophilicity, which facilitated the adhesion, proliferation, and differentiation of osteoblasts. Mechanistically, the Z/A/E composite scaffold promoted osteogenesis while concurrently inhibiting osteoclastogenesis, primarily through its ROS-scavenging capability. The bidirectional regulation of bone remodeling by the Z/A/E composite scaffold was demonstrated by significant repair of hydrogen peroxide-induced calvarial defects in ex vivo cultured explants from neonatal mice, confirmed by μ-CT and histological evaluation. Collectively, this Z/A/E composite scaffold, which leverages antioxidant activity to rebalance bone homeostasis, represents a promising strategy for bone regeneration.