κ-carrageenan, an algae-extracted polysaccharide known for its emulsifying properties, is widely used in food and beauty products. Because of its abundance in nature, similarity to natural glycosaminoglycans, and biocompatibility, it is a promising alternative to animal gelatin for tissue engineering. Key to the more widespread use of κ-carrageenan for biomedical applications is its processability, which is hampered by its temperature-dependent rheological properties. Here, a κ-carrageenan-based ink is introduced that can be 3D printed at room temperature through direct ink writing (DIW). This is achieved by formulating κ-carrageenan as microgels that are covalently crosslinked through a second network, resulting in double network granular hydrogels (DNGHs). These DNGHs can be stiffened to reach stiffnesses up to 0.9 MPa under tension and 1.1 MPa under compression through the addition of metal ions and glucose. The metal/glucose reinforcement also increases the work of fracture up to 1.1 MJ m⁻³, exceeding that of unmodified κ-carrageenan DNGHs 50-fold. The potential of the ink by room temperature 3D printing cm-sized free-standing load-bearing structures is demonstrated. This ink is envisaged to be a well-suited algae-derived alternative for the animal-based gelatin for tissue engineering and in food applications for example as soft confectionery products.

中文翻译：

---

3D 可打印的 κ-卡拉胶基颗粒水凝胶


κ-角叉菜胶是一种藻类提取的多糖，以其乳化特性而闻名，广泛用于食品和美容产品。由于其在自然界中含量丰富、与天然糖胺聚糖相似且具有生物相容性，它是组织工程中动物明胶的有前途的替代品。κ-卡拉胶在生物医学应用中更广泛使用的关键是其可加工性，而其可加工性受到其与温度相关的流变特性的阻碍。本文介绍了一种基于 κ-角叉菜胶的墨水，该墨水可以在室温下通过直接墨水书写 （DIW） 进行 3D 打印。这是通过将 κ-角叉菜胶配制成微凝胶来实现的，这些微凝胶通过第二个网络共价交联，从而产生双网络颗粒水凝胶 （DNGH）。通过添加金属离子和葡萄糖，这些 DNGH 可以进行加固，在拉伸下达到高达 0.9 MPa 的刚度，在压缩下达到 1.1 MPa 的刚度。金属/葡萄糖增强还使断裂功高达 1.1 MJ m ⁻³ ，超过未改性的 κ-卡拉胶 DNGHs 的 50 倍。通过室温 3D 打印厘米大小的独立承重结构，展示了墨水的潜力。这种油墨被认为是一种非常适合的藻类衍生替代品，用于组织工程和食品应用，例如作为软糖果产品。