3D Freeform Printing of Nanocomposite Hydrogels through in situ Precipitation in Reactive Viscous Fluid
3D Freeform Printing of Nanocomposite Hydrogels through in situ Precipitation in Reactive Viscous Fluid
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DOI：
10.18063/ijb.v6i2.258
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发表时间：
2020-01-01
影响因子：
8.4
通讯作者：
Song, Juha
中科院分区：
文献类型：
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作者：
Chen, Shengyang;Jang, Tae-Sik;Song, Juha
复合水凝胶作为三维（3D）打印生物材料，由于其增强的内在机械强度和生物活性，与纯水凝胶相比，得到了极大的关注。在用于复合水凝胶的大多数常规印刷方法中，在印刷之前将颗粒预加载在油墨中，这通常降低复合油墨的可印刷性，而由于物理混合的颗粒-水凝胶相互作用差而几乎没有机械改进。相比之下，在3D打印过程中将纳米颗粒原位掺入水凝胶中实现了颗粒的均匀分布，具有显著的机械增强作用，而溶解在油墨中的前体不会影响打印过程。在本文中，我们介绍了一种与杂交过程相结合的“液体打印”技术，该技术允许纳米颗粒增强复合水凝胶的3D自由打印。用于该打印系统的粘塑性基质不仅为打印的水凝胶长丝提供支撑，而且还提供化学反应物以在打印的物体中诱导各种反应用于原位改性。通过透明质酸（HAc）-藻酸盐（Alg）水凝胶墨水的这种3D自由打印，通过两步交联策略成功地制造了纳米复合水凝胶支架。Alg的第一离子交联在印刷期间提供结构稳定性，而光固化HAc的第二交联改善了纳米复合材料水凝胶的机械和生理稳定性。对于3D打印过程中的原位沉淀，将磷酸根离子溶解在水凝胶墨水中，并将钙离子添加到粘塑性基质中。与纯HAc相比，复合水凝胶在机械强度、生物稳定性以及生物性能方面表现出显著改善。此外，通过调节油墨的离子浓度，实现了不同磷酸钙含量的复合材料的多材料印刷。我们的方法通过打印材料的设计和修改以及反应性粘塑性基质中的原位打印后功能化和杂化，大大加速了具有复杂几何形状的各种功能或杂化材料的3D打印。
Composite hydrogels have gained great attention as three-dimensional (3D) printing biomaterials because of their enhanced intrinsic mechanical strength and bioactivity compared to pure hydrogels. In most conventional printing methods for composite hydrogels, particles are preloaded in ink before printing, which often reduces the printability of composite ink with little mechanical improvement due to poor particle-hydrogel interaction of physical mixing. In contrast, the in situ incorporation of nanoparticles into a hydrogel during 3D printing achieves uniform distribution of particles with remarkable mechanical reinforcement, while precursors dissolved in inks do not influence the printing process. Herein, we introduced a "printing in liquid" technique coupled with a hybridization process, which allows 3D freeform printing of nanoparticle-reinforced composite hydrogels. A viscoplastic matrix for this printing system provides not only support for printed hydrogel filaments but also chemical reactants to induce various reactions in printed objects for in situ modification. Nanocomposite hydrogel scaffolds were successfully fabricated through this 3D freeform printing of hyaluronic acid (HAc)-alginate (Alg) hydrogel inks through a two-step crosslinking strategy. The first ionic crosslinking of Alg provided structural stability during printing, while the secondary crosslinking of photo-curable HAc improved the mechanical and physiological stability of the nanocomposite hydrogels. For in situ precipitation during 3D printing, phosphate ions were dissolved in the hydrogel ink and calcium ions were added to the viscoplastic matrix. The composite hydrogels demonstrated a significant improvement in mechanical strength, biostability, as well as biological performance compared to pure HAc. Moreover, the multi-material printing of composites with different calcium phosphate contents was achieved by adjusting the ionic concentration of inks. Our method greatly accelerates the 3D printing of various functional or hybridized materials with complex geometries through the design and modification of printing materials coupled with in situ post-printing functionalization and hybridization in reactive viscoplastic matrices.