Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Biotechnol Bioeng. 2010 Apr 15;105(6):1178-86. doi: 10.1002/bit.22613.
One of the challenges in tissue engineering is to provide adequate supplies of oxygen and nutrients to cells within the engineered tissue construct. Soft-lithographic techniques have allowed the generation of hydrogel scaffolds containing a network of fluidic channels, but at the cost of complicated and often time-consuming manufacturing steps. We report a three-dimensional (3D) direct printing technique to construct hydrogel scaffolds containing fluidic channels. Cells can also be printed on to and embedded in the scaffold with this technique. Collagen hydrogel precursor was printed and subsequently crosslinked via nebulized sodium bicarbonate solution. A heated gelatin solution, which served as a sacrificial element for the fluidic channels, was printed between the collagen layers. The process was repeated layer-by-layer to form a 3D hydrogel block. The printed hydrogel block was heated to 37 degrees C, which allowed the gelatin to be selectively liquefied and drained, generating a hollow channel within the collagen scaffold. The dermal fibroblasts grown in a scaffold containing fluidic channels showed significantly elevated cell viability compared to the ones without any channels. The on-demand capability to print fluidic channel structures and cells in a 3D hydrogel scaffold offers flexibility in generating perfusable 3D artificial tissue composites.
组织工程面临的挑战之一是为工程组织构建内的细胞提供充足的氧气和营养供应。软光刻技术允许生成含有流体通道网络的水凝胶支架，但代价是复杂且通常耗时的制造步骤。我们报告了一种用于构建含有流体通道的水凝胶支架的三维（3D）直接打印技术。通过该技术还可以将细胞打印到支架上并将其嵌入支架中。胶原蛋白水凝胶前体通过雾化的碳酸氢钠溶液进行打印和随后交联。打印一层加热的明胶溶液，作为流体通道的牺牲元件，打印在胶原蛋白层之间。重复该过程以形成 3D 水凝胶块。将打印的水凝胶块加热至 37 度，允许明胶选择性地液化和排出，在胶原蛋白支架内产生中空通道。与没有任何通道的支架相比，在含有流体通道的支架中生长的皮肤成纤维细胞的细胞活力显著提高。在 3D 水凝胶支架中按需打印流体通道结构和细胞的能力为生成可灌注的 3D 人工组织复合材料提供了灵活性。
