Novel printing strategy for high fidelity extrusion-based bioprinted multi-material nested models.

Recent advances in drug development and tissue engineering have emphasized the need for precise 3D-printed multilayered blood vessel biomodels. Although existing extrusion-based models integrate biomaterials and cells, they often lack geometric fidelity, limiting their practical use in tissue engineering. This study addresses a key constraint in the generation of multi-material cylindrical constructs by developing a new printing protocol to enhance trajectory generation for extrusion-based multi-material nested cylindrical model bioprinting process. To overcome this challenge, we have developed a Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) software capable of generating multi-material nested cylindrical models and their printing trajectory using an innovative printing protocol. The protocol strategically modifies the starting point of each layer and avoids collisions during fabrication. Furthermore, it optimizes the printing order to minimize tool changes and enables flexible adjustment of photopolymerization timing and pathing. We have tested this approach on three multi-material tissue models and compared the results with the models generated using the BIOCAD software (RegenHU). Findings demonstrate that our protocol significantly improves cylindrical structure integrity, minimizes printing collisions and reduces overall printing time. Comparative analysis confirms the superior printing fidelity of the tissue models printed using our method, validating its effectiveness for extrusion-based cylindrical bioprinting applications. This optimized trajectory-generation approach provides a robust framework for creating physiologically accurate in vitro vascular models, potentially accelerating drug discovery and reducing the reliance on animal experimentation in biomedical research.近年来，药物开发与组织工程领域的前沿进展凸显了对高精度3D打印多层血管生物模型的迫切需求。尽管现有的基于挤出的生物模型已可整合生物材料与细胞，但往往几何保真度不足，限制了其在组织工程中的实际应用。本研究针对多材料圆柱结构体构建中的关键瓶颈，开发了全新的打印协议，以优化基于挤出的多材料嵌套圆柱模型生物打印流程中的轨迹生成环节。为攻克这一技术难题，我们开发了计算机辅助设计与计算机辅助制造（CAD/CAM）软件，可依托创新打印协议生成多材料嵌套圆柱模型及其对应的打印轨迹。该打印协议通过策略性调整每一层的起始点，避免了打印过程中的碰撞问题；此外，其还优化了打印顺序以减少工具更换次数，并可灵活调整光聚合时机与打印路径。我们通过三种多材料组织模型对该方法进行了测试，并将生成结果与使用BIOCAD软件（RegenHU）生成的模型进行了对比。实验结果表明，本研究提出的打印协议可显著提升圆柱结构的完整性，大幅降低打印碰撞概率，并缩短整体打印时长。对比分析进一步证实，采用本方法打印的组织模型具有更优异的打印保真度，验证了其在基于挤出的圆柱生物打印场景中的应用有效性。这种优化后的轨迹生成方法为构建生理精准的体外血管模型提供了可靠的技术框架，有望加速药物发现进程，并减少生物医学研究中对动物实验的依赖。