Zinc-Based Tannin-Modified Composite Microparticulate Scaffolds with Balanced Antimicrobial Activity and Osteogenesis
Yitao Zhao1, Jintao Li1, Lingli Liu1
1Department of Histology and Embryology, School of Basic Medical Sciences, Department of Orthopedic Surgery, Guangdong Provincial Key Laboratory of Bone and Joint Degeneration Diseases, The Third Affiliated Hospital of Southern Medical University, Southern Medical University, Guangzhou, 510515, P. R. China.
Abstract:
Treatment of infected bone defects is a major clinical challenge; bioactive materials combining sufficient antimicrobial activity and favorable osteogenic ability are urgently needed. In this study, through a facile one-pot hydrothermal reaction of zinc acetate in the presence of tannic acid (TA), with or without silver nitrate (AgNO3 ), is used to synthesize a TA or TA and silver nanoparticles (Ag NPs) bulk-modified zinc oxide (ZnO) (ZnO-TA or ZnO-TA-Ag), which is further composited with zein to fabricate porous microparticulate scaffolds for infected bone defect repair. Bulk TA modification significantly improves the release rate of antibacterial metal ions (Zn2+ release rate is >100 times that of ZnO). Fast and long-lasting (>35 d) Zn2+ and Ag+ release guaranteed sufficient antibacterial capability and excellent osteogenic properties in promoting the osteogenic differentiation of bone marrow mesenchymal stem cells and endogenous citric acid production and mineralization and providing considerable immunomodulatory activity in promoting M2 polarization of macrophages. At the same time, synchronously-released TA could scavenge endogenous reactive oxygen species (ROS) and ROS produced by antibacterial metal ions, effectively balancing antibacterial activity and osteogenesis to sufficiently control infection while protecting the surrounding tissue from damage, thus effectively promoting infected bone defect repair.
