## 3 Results and Discussion
### Evaluation of the Photothermal Properties of Bone Scaffolds  
To assess the photothermal properties of the photothermal-sensitive nanocomposite SiO2@Fe3O4, the PVA/HA/\(\beta\)-TCP/PCL composite bone scaffold (control group) and varying mass fractions of the photothermal composite bone scaffolds were subjected to 808 nm (2 W/cm\({}^{2}\)) irradiation for 60 s at room temperature. The control group and the 3%, 5%, 7% photothermal composite bone scaffolds demonstrated temperature increases of 2.92 \({}^{\circ}\)C, 27.26 \({}^{\circ}\)C, 38.48 \({}^{\circ}\)C, and 52.88 \({}^{\circ}\)C, respectively. Relative to the control group, all photothermal composite bone scaffolds exhibited notably elevated temperatures in a short duration, affirming the superior photothermal properties of the photothermal-sensitive nanocomposite SiO2@Fe3O4. In order to simulate the functional characteristics of photothermal composite bone scaffolds within different patient environments, control groups and photothermal composite scaffolds were placed within culture dishes. Specifically, tissue blocks of varying thicknesses (3, 5, 7, 9 mm; porcine tissue blocks) were positioned atop the scaffolds, while 2 mm tissue blocks were situated at the scaffold base to establish a sealed environment, thereby insulating the scaffold from external influences on temperature. It is noted that the optimal temperature range for promoting osteoblast differentiation falls between 40 and 43 \({}^{\circ}\)C [24]; temperatures exceeding this range may compromise the structural integrity of bone tissue cells, thus impeding their normal functionality and differentiation capacity. Conversely, lower temperatures are insufficient to induce osteogenic differentiation. However, SiO2@Fe3O4 demonstrates remarkable photothermal conversion capabilities, rendering it an optimal material for photothermal composite bone scaffolds. Upon irradiation by a near-infrared device within a tissue block, the absorbed light energy elicits the excitation of electrons into a highly energetic state. Subsequently, these excited electrons undergo a non-radiative relaxation process, efficiently converting the absorbed light energy into lattice vibrational energy or thermal kinetic energy of the electrons. This generates a thermal effect that attains the desired temperature for enhancing osteogenic differentiation. Illustratively, as depicted in Figure 8, a substantial temperature differential is observed between the control group and the photothermal composite scaffold, underscoring the superior photothermal properties inherent to the latter. Following a period of 90 s of near-infrared light exposure, an increase in internal temperature is registered within the PVA/HA/\(\beta\)-TCP/PCL composite bone scaffold. However, this temperature escalation does not attain the requisite threshold for fostering osteoblast differentiation. Prolonged irradiation poses the risk of inflicting damage upon superficial skin tissues. Notably, while the 3% photothermal composite scaffold exhibits a degree of photothermal efficacy, the disparate thickness of patient tissues precludes the standardization of irradiation durations necessary to elevate the scaffold temperature by 3-6 \({}^{\circ}\)C for the promotion of osteogenic differentiation. Conversely, the 7% photothermal composite scaffold, when subjected to a 30-s  
Figure 7: Compressive strength of the composite scaffold. irradiation, elevates the temperature of sealed scaffolds with varying tissue thicknesses by 3-6 \({}^{\circ}\)C. However, owing to the robust photothermal attributes of the 7% composite scaffold, precise modulation of the near-infrared light exposure duration is imperative to preclude deleterious thermal effects on bone tissue cells. Conversely, the 5% photothermal composite scaffold, upon 40-45 s of irradiation, facilitates a 3-6 \({}^{\circ}\)C temperature increase across varying tissue thicknesses, thereby reaching the optimal temperature range of 40-43 \({}^{\circ}\)C for promoting osteogenic differentiation.