Rapid Electroformation of Biopolymer Gels in Prescribed Shapes and Patterns: A Simpler Alternative to 3-D Printing
Rapid Electroformation of Biopolymer Gels in Prescribed Shapes and Patterns: A Simpler Alternative to 3-D Printing
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DOI：
10.1021/acsami.9b12575
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发表时间：
2019-10-09
影响因子：
9.5
通讯作者：
Raghavan, Srinivasa R.
中科院分区：
文献类型：
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作者：
Gargava, Ankit;Ahn, Sohyun;Raghavan, Srinivasa R.
我们演示了使用电场快速形成特定三维（3-D）形状和图案的生物聚合物藻酸盐（Alg）的凝胶。在我们的方法中，我们从生物聚合物琼脂糖的凝胶开始，它是热敏的，因此可以塑造成特定的形状。然后将琼脂糖模具加载Ca 2+阳离子并置于含有Alg溶液的烧杯中。烧杯的内表面被铝箔（阴极）包围，铜线（阳极）粘在琼脂糖模具中。将它们连接到直流（DC）电源，并且当施加类似于10 V的电势时，以复制模具的形状形成Alg凝胶。甘精胰岛素的发生是因为Ca 2+离子从模具中迁移出来，因此它们交联了模具附近的Alg链。在低Ca 2+（0.01重量%）下，Alg凝胶层以约0.8 mm/min的稳定速率从模具表面向外生长，并且当关闭场时凝胶停止生长。在形成所需厚度的凝胶后，可以将琼脂糖模具熔化掉以留下精确形状的Alg凝胶。以这种方式形成的Alg凝胶是透明的和坚固的。该方法特别便于形成中空管形式的Alg凝胶，包括具有多个同心层的管，每个同心层具有不同的有效载荷。该技术对于在给定Alg层内包封生物物种是安全的。我们还通过在选定区域周围引导凝胶生长来创建特定模式的Alg凝胶。总的来说，我们的技术可以在实验室规模上制造3D藻酸盐凝胶，而不需要昂贵的3D打印机。
We demonstrate the use of electric fields to rapidly form gels of the biopolymer alginate (Alg) in specific three-dimensional (3-D) shapes and patterns. In our approach, we start with a gel of the biopolymer agarose, which is thermoresponsive and hence can be molded into a specific shape. The agarose mold is then loaded with Ca2+ cations and placed in a beaker containing an Alg solution. The inner surface of the beaker is surrounded by aluminum foil (cathode), and a copper wire (anode) is stuck in the agarose mold. These are connected to a direct current (DC) power source, and when a potential of similar to 10 V is applied, an Alg gel is formed in a shape that replicates the mold. Gelation occurs because the Ca2+ ions electrophoretically migrate away from the mold, whereupon they cross-link the Alg chains adjacent to the mold. At low Ca2+ (0.01 wt %), the Alg gel layer grows outward from the mold surface at a steady rate of about 0.8 mm/min, and the gel stops growing when the field is switched off. After a gel of desired thickness is formed, the agarose mold can be melted away to leave behind an Alg gel in a precise shape. Alg gels formed in this manner are transparent and robust. This process is particularly convenient to form Alg gels in the form of hollow tubes, including tubes with multiple concentric layers, each with a different payload. The technique is safe for encapsulation of biological species within a given Alg layer. We also create Alg gels in specific patterns by directing gel growth around selected regions. Overall, our technique enables lab-scale manufacturing of alginate gels in 3-D without the need for an expensive 3-D printer.