Department of Bioengineering, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India.
Department of Mechanical Engineering, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India.
J Mater Chem B. 2024 Jun 12;12(23):5678-5689. doi: 10.1039/d4tb00437j.
Current additive manufacturing technologies wherein as-printed simple two-dimensional (2D) structures morph into complex tissue mimetic three-dimensional (3D) shapes are limited to multi-material hydrogel systems, which necessitates multiple fabrication steps and specific materials. This work utilizes a single shape memory thermoplastic polymer (SMP), PLMC (polylactide--trimethylene carbonate), to achieve programmable shape deformation through anisotropic design and infill angles encoded during 3D printing. The shape changes were first computationally predicted through finite element analysis (FEA) simulations and then experimentally validated through quantitative correlation. Rectangular 2D sheets could self-roll into complete hollow tubes of specific diameters (ranging from ≈6 mm to ≈10 mm) and lengths (as long as 40 mm), as quantitatively predicted from FEA simulations within one minute at relatively lower temperatures (≈80 °C). Furthermore, shape memory properties were demonstrated post-shape change to exhibit dual shape morphing at temperatures close to physiological levels. The tubes (retained as the permanent shape) were deformed into flat sheets (temporary shape), seeded with endothelial cells (at < ), and thereafter triggered at ≈37 °C back into tubes (permanent shape), utilizing the shape memory properties to yield bioresorbable tubes with cellularized lumens for potential use as vascular grafts with improved long-term patency. Additionally, out-of-plane bending and twisting deformation were demonstrated in complex structures by careful control of infill angles that can unprecedently expand the scope of cellularized biomimetic 3D shapes. This work demonstrates the potential of the combination of shape morphing and SMP behaviors at physiological temperatures to yield next-generation smart implants with precise control over dimensions for tissue repair and regeneration.
目前的增材制造技术，其中打印出的简单二维（2D）结构可以变成复杂的组织仿生三维（3D）形状，仅限于多材料水凝胶系统，这需要多个制造步骤和特定的材料。本工作利用单一形状记忆热塑性聚合物（SMP），PLMC（聚丙交酯-三亚甲基碳酸酯），通过各向异性设计和在 3D 打印过程中编码的填充角度来实现可编程的形状变形。形状变化首先通过有限元分析（FEA）模拟进行计算预测，然后通过定量相关性进行实验验证。矩形 2D 薄片可以自行卷成特定直径（约 6 毫米至 10 毫米）和长度（长达 40 毫米）的完整空心管，这与 FEA 模拟的定量预测一致，在相对较低的温度（约 80°C）下在一分钟内完成。此外，通过形状记忆性能的演示，在接近生理水平的温度下展示了双重形状变形。管（保留为永久形状）被变形为薄片（临时形状），接种内皮细胞（在 < 时），此后在约 37°C 下触发回到管（永久形状），利用形状记忆性能生成具有细胞化内腔的可生物吸收管，作为具有改善的长期通畅性的血管移植物的潜在用途。此外，通过仔细控制填充角度，在复杂结构中演示了面外弯曲和扭曲变形，这可以前所未有地扩展细胞化仿生 3D 形状的范围。本工作展示了在生理温度下结合形状变形和 SMP 行为的潜力，以产生具有精确尺寸控制的下一代智能植入物，用于组织修复和再生。
