Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot 7610001, Israel.
Langmuir. 2021 Jun 1;37(21):6451-6458. doi: 10.1021/acs.langmuir.1c00553. Epub 2021 May 19.
New ink compositions for direct ink writing (DIW) printing of hydrogels, combining superior rheological properties of cellulose nanocrystals (CNCs) and a water-compatible photoinitiator, are presented. Rapid fixation was achieved by photopolymerization induced immediately after the printing of each layer by 365 nm light for 5 s, which overcame the common height limitation in DIW printing of hydrogels, and enabled the fabrication of objects with a high aspect ratio. CNCs imparted a unique rheological behavior, which was expressed by orders of magnitude difference in viscosity between low and high shear rates and in rapid high shear recovery, without compromising ink printability. Compared to the literature, the presented printing compositions enable the use of low photoinitiator concentrations at a very short build time, 6.25 s/mm, and are also curable by 405 nm light, which is favorable for maintaining viability in bioinks.
本文提出了一种新的用于水凝胶直接墨水书写（DIW）打印的墨水组合物，它结合了纤维素纳米晶体（CNC）的优异流变性能和一种水相溶性的光引发剂。通过在每一层打印后立即用 365nm 光照射 5s 进行光聚合，实现了快速固定，克服了 DIW 打印水凝胶的常见高度限制，从而能够制造具有高纵横比的物体。CNC 赋予了独特的流变行为，其表现为在低剪切速率和高剪切恢复时的粘度之间存在数量级的差异，而不会影响墨水的可印刷性。与文献相比，本文提出的打印组合物能够在非常短的构建时间（6.25s/mm）下使用低浓度的光引发剂，并且可以用 405nm 光固化，这有利于在生物墨水中保持细胞活力。
