Additive manufacturing of graphene oxide-doped SiOC/Si ₃N ₄ photothermal functional bioceramic scaffolds through stereolithography technology

Clinical photothermal therapy for preventing bone tumor recurrence faces dual challenges: systemic toxicity risks from intravenous photosensitizer delivery and insufficient control of photothermal specificity. To address these limitations, we developed a stereolithography (SLA)-based additive manufacturing system for fabricating graphene oxide (GO)-reinforced SiOC/Si₃N₄ bioceramic scaffolds that integrate three functional components: a mechanically robust Si₃N₄ matrix, photothermally active SiOC, and osteoinductive GO. Initially, the polysiloxane KH570-H was synthesized, functioning as both a SiOC precursor and a photosensitive polymer, and subsequently formulated with 0-0.8 wt% GO/Si₃N₄ to develop SLA-compatible ceramic slurries. To address GO-induced light scattering defects, a GO content-photosensitive parameters predictive model was established, improving the dimensional accuracy of printed green bodies by 12.5% compared to non-optimized counterparts. Following sintering post-treatment, 0-0.8 wt% GO/SiOC/Si₃N₄ composite ceramics were fabricated, with the 0.2 wt% GO variant sintered at 1,300^oC demonstrating optimal multifunctional performance. The compressive strength of the Gyroid unit TPMS scaffold with a porosity of 60% reached 41.88 MPa. Notably, the 0.2 wt% GO formulation showed superior cell proliferative capacity, as evidenced by fluorescence microscopy observations of confluent cell monolayers with extensive pseudopodial extensions, indicative of active osteogenic interactions. Under 808 nm near-infrared irradiation (1 W/cm²), the scaffold achieved rapid photothermal activation, reaching the therapeutic threshold of 47.8°C within 10 minutes in a physiomimetic microenvironment. This photothermally functional GO/SiOC/Si₃N₄ scaffold offers a promising dual-functional solution for post-tumor bone regeneration, combining structural adaptability with spatiotemporally controlled therapeutic precision.