Researchers from德克萨斯农工大学已经结合了3D打印，生物材料工程和干细胞生物学，以创建新的，更高效，可定制的骨移植材料。
利用这三种技术，科学家生产了3D印刷的高度骨架脚手架，不仅促进了骨细胞的生长，而且还可以作为定制形状骨再生的坚固平台。新型的生物材料可以代表在重建手术中使用金属和聚合物的替代方法，而皮肤移植物能够在愈合后无缝整合到患者的头骨中。
生物医学工程系副教授罗兰·考纳斯（Roland Kaunas）说：“用于颅面骨植入物的材料要么是生物学上的无活性和极其硬的材料，例如钛，或者在生物学上活跃并且像生物聚合物一样柔软。”“在我们的研究中，我们开发了一种合成的聚合物，既具有生物活性又具有机械性能。这些材料也是3D可打印的，可以使定制的颅面植入物在美学上令人愉悦且实用。”
需要改善骨移植技术的需求
Each year 200,000 people suffer injuries to their jaw bone, face, or head. The resulting surgery often requires the use of titanium plates and screws to hold these broken bones in place, and to enable surrounding bone cells to grow, and form a cover around the implant. While this approach has achieved the relative success of aiding bone repair, titanium does not always integrate into bone tissue, which can then cause the implant to fail, and in advanced cases lead to further surgery.
Metals and thermoplastics are also more susceptible to infection, implant extrusion and exposure, tissue necrosis, and stress shielding compared to autologous grafts. Bone transplants are considered a preferable alternative by surgeons, but this technique has drawbacks too. Direct application of bone tissues relies on a limited source of donor tissues, incurs donor-site morbidity, and even then, complex geometries of bone in the skull cannot be easily replicated.
研究人员确定了生物相容性的聚合物，更具体地说是沼气，是聚合物和金属植入物的替代品。这些可延展的材料是可取的，因为一旦将骨干细胞加载，凝胶就可以将凝胶印在任何预编程的形状中。此外，与金属镀层不同，人体可以随着时间的推移溶解水凝胶，而不会造成任何持久损害。
Using 3D printed biogels to create bone transplants
Although the pliability of biogels makes them ideal for 3D bioprinting, their flexibility also impacts on the mechanical integrity and accuracy of any parts produced. In order to make the material more rigid, the researchers developed a Nanoengineered Ionic-Covalent Entanglement or “NICE.” The recipe for this concoction includes just three main ingredients: an extract from seaweed called kappa carrageenan, gelatin, and nanosilicate particles. These elements act to stimulate bone growth and mechanically reinforce the NICE hydrogel, with the mixture found to be more than eight times stronger than its individual components.
Once the blend had been prepared, the researchers added adult stem cells to 3D parts printed with NICE ink, and then chemically induced the stem cells to convert them into bone cells. Within two weeks of the process, the scientists found that the cells had grown in numbers, producing high levels of bone-associated proteins, minerals, and other molecules. The cell secretions formed a scaffold, known as an extracellular matrix, with a unique composition of biological materials needed for the growth and survival of developing bone cells. Once the scaffolds were fully-developed, the bone cells could be removed, and the hydrogel-based implant was ready to be inserted into the site of the skull injury.
根据研究人员的说法，3D印刷支架的强度促进了健康骨细胞的附着和生长，同时允许发育的骨细胞通过合成材料穿透。水凝胶还具有弹性且坚韧，可以手动操作，同时也有略有压缩，并允许压入缺陷。由于良好的移植物具有有希望的生物学和物理特性，研究人员渴望在不久的将来使用体内骨再生的过程。
考纳斯说：“尽管我们目前的工作集中在修复颅骨上，但在不久的将来，我们希望扩大这项技术，不仅是颅面上的缺陷，而且还要在脊柱融合和其他伤害的情况下进行骨骼再生。”
Bone grafting in additive manufacturing
实验性的新生物材料目前是3D打印中的热门话题，许多学术机构试图完善用于骨干目的的技术。
The university clinicCharité -Universitätsmedizin柏林，开发的3D打印titanium-mesh scaffolds2018年1月，使用患者自己的骨头提供传统的骨织骨技术的替代方法。科学家声称植入物提供了无与伦比的强度，并且可以使用复杂的内几何形状设计以适应任何伤害。
来自康涅狄格州的研究人员牛津表演材料（OPM）和麦吉尔大学在加拿大，使用3D打印的北京植入物为了在2019年6月加速骨骼再生。这种新提出的方法可以帮助治疗关键尺寸的骨骼缺陷，从而减少了对侵入性手术（例如骨移植）的需求。
科学家来自莱斯大学和马里兰大学（UMD）于2019年4月开发了针对3D印刷人造骨组织的新概念证明。该软骨是为了帮助运动员从运动损伤中恢复过来，以及患有与关节炎有关的损害的运动员。
研究人员的发现在其论文中详细介绍了“3D打印的纳米工程的离子 - 蛋白蛋白 - 纠缠支架与IP-HMSC衍生矩阵，”发表在先进的医疗保健材料杂志。这项研究由Candice Sears，Eli Mondragon，Zachary I. Richards，Nick Sears，David Chimene，Eoin P. McNeill，Carl A. Gregory，Akhilesh K. Gaharwar和Roland Kaunas共同撰写。
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特色图像显示了头骨的3D模型，其中研究员的生物材料移植物内部。通过德克萨斯A＆M的照片。
