Additive manufacturing of graphene oxide-doped SiOC/Si <sub>3</sub>N <sub>4</sub> photothermal functional bioceramic scaffolds through stereolithography technology
Yange Li, Hongyu Xing, Lei Lai, Hui Li, Hongyu Zhao, Qingguo Lai, Bin Zou
Abstract
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/Si<sub>3</sub>N<sub>4</sub> bioceramic scaffolds that integrate three functional components: a mechanically robust Si<sub>3</sub>N<sub>4</sub> 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/Si<sub>3</sub>N<sub>4</sub> 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/Si<sub>3</sub>N<sub>4</sub> composite ceramics were fabricated, with the 0.2 wt% GO variant sintered at 1,300<sup>o</sup>C 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/Si<sub>3</sub>N<sub>4</sub> scaffold offers a promising dual-functional solution for post-tumor bone regeneration, combining structural adaptability with spatiotemporally controlled therapeutic precision.