Interfacial design, degradation behaviour and biofunctionality of biodegradable Zn matrix composites developed via Fe2O3@GO-induced in-situ reaction

• A novel in situ wetting strategy was employed to develop high performance Zn-based biocomposite. • A unique ZnO and FeZn 13 dual-phase interface was achieved between the Zn matrix and reinforcements. • The in-situ short-term immersion test revealed that corrosion selectivity primarily associated with Cl- invasion process and galvanic corrosion. • Transcriptomic sequencing analysis further confirms that the 2.5Fe 2 O 3 @GO/Zn biocomposite significantly up-regulated osteogenic differentiation-relevant gene expression (Bmp4, Tgfb1, Id and so on) via TGF-beta signal pathway, thereby contributing to excellent osteogenic capability. • The synergistic effect of Zn 2+ ions, ZnO nanoparticles, ROS and GO sheets contributed substantial antibacterial activity of Fe 2 O 3 @GO/Zn biocomposites against S. aureus. Biodegradable zinc (Zn) matrix composites hold significant potential for orthopedic applications due to their moderate degradation rate, good biocompatibility, and controllable biofunctionality. However, inadequate interfacial adhesion between the Zn matrix and reinforcing components significantly compromises the mechanical performance and biological functionality of Zn matrix biocomposites, limiting their clinical translation potential. Herein, a novel Fe 2 O 3 -induced in-situ wetting method was well-designed to improve the interfacial properties in Zn-based biocomposites. The incorporation of Fe 2 O 3 -modified graphene oxide (GO) triggered an in situ redox reaction during the consolidation process, forming a nanoscale dual-phase interlayer consisting of ZnO and FeZn 13 , which effectively strengthened the interfacial bonding between the GO reinforcement and Zn matrix. As a result, the yield strength (YS) significantly increased to 187.3 ± 7.5 MPa following the incorporation of 2.5 wt% Fe 2 O 3 @GO, and moderate degradation rates of 0.13 to 0.22 mm·y −1 are confirmed in Fe 2 O 3 @GO/Zn biocomposites. In vitro, the 50 % and 25 % composites’ extracts exhibited no cytotoxicity to MC3T3-E1 cells. Transcriptomic sequencing technology revealed that the experimental composites induced the activation of TGF-beta signaling pathways in model cells by elevating the expression of Bmp, Id, Tgfb, Myc, and Rb genes, thereby promoting osteogenesis. In the meantime, an antibacterial rate exceeding 90 % against S. aureus was confirmed in the 2.5 wt% Fe 2 O 3 @GO/Zn biocomposites.