Diatom-Inspired Scaffold for Infected Bone Defect Therapy: Achieving Stable Photothermal Properties and Coordinated
Xinyi Li1, Yifei Yang2, Mingxuan Chen1
1State Key Laboratory of Oral Diseases, National Center for Stomatology, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
Advanced Materials (Deerfield Beach, Fla.)
|September 10, 2025
Summary
This study presents a novel biomimetic scaffold for bone defect repair. The scaffold combines chitosan-hydroxyapatite with copper-doped iron nanoparticles and silica, effectively treating infections and promoting bone regeneration.
Area of Science:
- Biomaterials Science
- Nanotechnology
- Regenerative Medicine
Background:
- Bacterial infections and inflammation impede bone regeneration and implant stability.
- Iron oxide nanoparticles offer biocompatibility but struggle with combined antibacterial, immunomodulatory, and bone regenerative functions.
- Current therapies for infectious bone defects require improved multifunctional solutions.
Purpose of the Study:
- To develop a biomimetic scaffold integrating copper-doped iron goethite (Fe(Cu)OOH) nanoparticles and a mesoporous SiO2 layer onto a chitosan-hydroxyapatite (CH) base for infectious bone defect treatment.
- To achieve synergistic antibacterial, immunomodulatory, and osteogenic activities for enhanced bone repair.
- To leverage diatom-inspired design for multifunctional therapeutic benefits.
Main Methods:
- Fabrication of a multifunctional bone repair scaffold (CH/FeCu@SiO2) using chitosan-hydroxyapatite, copper-doped iron goethite nanoparticles, and a mesoporous SiO2 protective layer.
- Utilized near-infrared (NIR) light to induce mild hyperthermia and Cu2+ release for antibacterial effects.
- Assessed antioxidant activity, M2 macrophage polarization, TGF-β signaling pathway modulation, and osteoclast differentiation inhibition.
- Evaluated bone regeneration and defect repair efficacy in vitro and in vivo models.
Main Results:
- The CH/FeCu@SiO2 scaffold achieved >99% antibacterial efficacy via hyperthermia and Cu2+ release.
- Fe(Cu)OOH nanoparticles demonstrated significant ROS scavenging (69.20%) and promoted M2 macrophage polarization (1.64-fold).
- Mild hyperthermia and ion release promoted vascularized bone regeneration and defect repair (1.3-fold) by upregulating TGF-β signaling and inhibiting osteoclastogenesis.
- The scaffold successfully created an osteogenic immune microenvironment, protecting stem cells.
Conclusions:
- The diatom-inspired CH/FeCu@SiO2 scaffold exhibits synergistic antibacterial, immunomodulatory, and osteogenic properties.
- This multifunctional biomaterial offers a promising therapeutic strategy for treating infectious bone defects.
- The developed scaffold effectively addresses the limitations of current iron oxide nanoparticle-based therapies.
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