3D-printed nanoclay-encapsulated povidone-iodine hydrogel scaffolds for osteomyelitis therapy

Conventional treatments for bone infections (e.g., osteomyelitis) are often plagued by incomplete eradication, antibiotic resistance, and poor biocompatibility/structural adaptability of grafts/implants, creating an urgent demand for advanced therapeutic platforms. In this context, the integration of 3D printing with antibacterial materials emerges as a promising strategy for personalized bone infection therapy. Herein, we report a novel antibacterial therapeutic system, wherein a facile fabrication approach enables the synergistic interplay of constituent materials to simultaneously enhance printability and achieve a robust antibacterial effect. The sodium alginate/methylcellulose (SAM) hydrogel inherently possesses excellent printability; upon the incorporation of hollow tubular halloysite nanotubes (HNTs) into the SAM network, the HNTs disperse uniformly, which remarkably strengthens the shear-thinning behavior of the hydrogel and improves the structural resolution of 3D-printed constructs. Furthermore, HNTs serve as efficient drug carriers for povidone-iodine (PVP-I)—a broad-spectrum antimicrobial agent that exerts potent bactericidal activity against pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) without eliciting antibiotic resistance. The resultant system exhibits superior 3D printability; after Ca 2+ cross-linking, the printed scaffolds retain the typical porous architecture of alginate-based hydrogels while demonstrating enhanced biocompatibility. Notably, in vitro experiments prove that hydrogels doped with HNTs or HNTs/PEI/PVP-I also exert a promotive effect on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Co-culture experiments with MRSA validate the robust antibacterial efficacy of the system, which achieves a 99% bactericidal rate within 30 minutes. Collectively, this work highlights the great potential of this 3D-printable hydrogel platform for bone infection treatment. While further in vivo validation and mechanistic exploration are warranted to fully establish its translational potential, this versatile system represents a viable candidate for the development of advanced antimicrobial scaffolds tailored for osteomyelitis therapy.