Free-form printing offers a novel biofabrication approach to generate complex shapes by depositing hydrogel materials within a temporary supportive environment. However, printed hydrogels typically lack the requisite mechanical properties and functionality of the desired tissue, limiting application and, more importantly, safety and efficacy of the implant. The study authors have developed an innovative nanoclay-based bioink to print high shape fidelity functional constructs for potential skeletal application. Laponite® (LAP) nanoclay was combined with gellan gum (GG) to generate a printable hydrogel that was highly stable in vitro, displayed limited swelling ability compared with the silicate-free control and remained stable over time. An agarose fluid gel was found to provide the requisite support for the deposition of the material ink and preservation of the printed structure before crosslinking. Printed C2C12 myoblasts remained viable and displayed extensive proliferation over 21 days in culture. Cell-laden scaffolds demonstrated functionality within 1 day of culture in vitro and that was preserved over 3 weeks. Analysis of absorption and release mechanisms from LAP-GG using model proteins (lysozyme and bovine serum albumin) demonstrated the retention capability of the clay-based materials for compound localisation and absence of burst release. Vascular endothelial growth factor ​was loaded within the agarose fluid gel and absorbed by the material ink via absorption during deposition. The 3D-printed constructs were implanted on the chorioallantoic membrane of a 10-day-old developing chick. Extensive and preferential vasculature infiltration was observed in LAP-GG–loaded vascular endothelial growth factor constructs compared with controls (p<0.01 and p<0.0001) after only 7 days of incubation. The current studies demonstrate, for the first time, the application of innovative LAP-GG 3D constructs in the generation of growth factor–loaded 3D constructs for potential application in skeletal tissue repair.

自由形式印刷提供了一种新颖的生物制造方法，通过在临时的支撑环境中沉积水凝胶材料来生成复杂的形状。但是，印刷的水凝胶通常缺乏所需组织所需的机械性能和功能，从而限制了应用，更重要的是，还限制了植入物的安全性和功效。该研究的作者开发了一种创新的基于纳米粘土的生物墨水，可打印高形状保真度的功能结构，以用于潜在的骨骼应用。Laponite®（LAP）纳米粘土与吉兰糖胶（GG）结合使用，产生可印刷的水凝胶，该凝胶在体外高度稳定，与不含硅酸盐的对照相比，它显示出有限的溶胀能力，并且随时间保持稳定。发现琼脂糖流体凝胶为交联之前的材料油墨的沉积和印刷结构的保存提供了必要的支持。印刷的C2C12成肌细胞在培养21天后仍保持活力并显示出广泛的增殖。载有细胞的支架在体外培养的1天内表现出功能并保存了3周以上。使用模型蛋白（溶菌酶和牛血清白蛋白）对LAP-GG的吸收和释放机理进行分析，证明了粘土基材料对化合物定位的保留能力，并且没有爆发释放。血管内皮生长因子负载在琼脂糖液体凝胶中，并在沉积过程中通过吸收被材料墨水吸收。将3D打印的构建体植入到10天大的发育中小鸡的绒毛膜上。与对照组相比，在加载LAP-GG的血管内皮生长因子构建物中观察到广泛的优先血管浸润（p <0.01和p<0.0001）孵育后仅7天。当前的研究首次证明了创新型LAP-GG 3D构建体在生成生长因子的3D构建体中的应用，有望在骨骼组织修复中应用。