## 1 Introduction  
The repair of bone defects has long been a formidable challenge in the field of bone tissue engineering [1, 2]. Bone defects resulting from surgical procedures or traumatic injuries exceeding the critical dimension of 10 mm manifest an inherent incapacity for structural bone regeneration [3, 4]. To enhance the capability of bone scaffolds in inducing bone gene expression and facilitating bone cell regeneration, a strategy involving the combination of two or more types of biomaterials is employed to leverage the respective advantages of different biomaterials, thereby achieving the requisite criteria of native bone biocompatibility, porosity, and mechanical properties [5]. The bio-ceramic material hydroxyapatite (HA) is distinguished by its exceptional biocompatibility and stability and can be co-extruded with a polyvinyl alcohol (PVA) solution for the fabrication of bone scaffolds [6, 7, 8]. Its unique property of bonding directly to bone without forming any surrounding connective tissue has found widespread applications in various fields, such as bone scaffolds and coatings for dental implants [9, 10]. Bio-ceramic materials, like beta-tricalcium phosphate (\(\beta\)-TCP) and HA, exhibit a high degree of resemblance to natural bone tissue, and a composite scaffold combining \(\beta\)-TCP and HA can address the degradation limitations of HA scaffolds made from a single material. Furthermore, the incorporation of the polymer biomaterial polycaprolactone (PCL) is beneficial for enhancing the mechanical performance of composite bone scaffolds owing to its superior toughness [11]. [PERSON] and colleagues have validated that the mechanical properties of HA/\(\beta\)-TCP composite bone scaffolds are notably improved via the infiltrative effect of PCL. Additionally, they assessed the cell compatibility of the scaffolds by culturing human bone marrow mesenchymal stromal cells in vitro, demonstrating their favorable cell compatibility, enhanced cell proliferation, and non-cytotoxicity. This underscores the potential of these biomaterials in bone tissue engineering applications [12]. Localized hyperthermia is a widely utilized adjunctive therapeutic modality in clinical practice, known for its ability to expedite cellular metabolism, stimulate cell proliferation, and induce the expression of pertinent genes to facilitate the regeneration of bone tissue defects [13]. Traditional thermal therapy methods utilizing near-infrared light devices have limitations in effectively elevating the temperature of internal scaffolds, potentially resulting in adverse effects, such as skin burns, with prolonged exposure. Scaffolds incorporating thermosensitive compounds can be swiftly heated within the body through modulation by near-infrared light devices [14; 15]. Nevertheless, challenges exist with organic photothermal agents due to their suboptimal photothermal stability and susceptibility to photobleaching effects, while the intricate fabrication processes associated with carbon nanomaterials and the heightened toxicity risks of noble metal nanomaterials present additional drawbacks. In contrast, photothermal-responsive Fe\({}_{3}\)O\({}_{4}\) nanoparticles offer distinct advantages, including high stability, facile synthesis, low toxicity, and superior photothermal properties [16]. However, the propensity of Fe\({}_{3}\)O\({}_{4}\) particles for aggregation necessitates modification for effective integration with scaffold materials to explore their full potential in harnessing photothermal properties. This study aimed to promote the proliferation of bone tissue cells and induce the expression of bone-related genes by utilizing the hydrolysis-condensation method to synthesize photothermal-sensitive SiO\({}_{2}\)@Fe\({}_{3}\)O\({}_{4}\) nanoparticles, thereby endowing them with excellent biocompatibility, stability, and negligible cytotoxicity, while preventing Fe\({}_{3}\)O\({}_{4}\) particle aggregation [17]. Subsequently, a photothermal composite scaffold was fabricated using a state-of-the-art 3D bioprinting technique.