University of Texas at El Paso, W.M. Keck Center for 3-D Innovation, 500 W. University Ave., Engineering Building, Rm. 108, El Paso, TX 79968-0521, USA.
Acta Biomater. 2010 Mar;6(3):1047-54. doi: 10.1016/j.actbio.2009.08.017. Epub 2009 Aug 14.
Challenges remain in tissue engineering to control the spatial, mechanical, temporal and biochemical architectures of scaffolds. Unique capabilities of stereolithography (SL) for fabricating multi-material spatially controlled bioactive scaffolds were explored in this work. To accomplish multi-material builds, a mini-vat setup was designed allowing for self-aligning X-Y registration during fabrication. The mini-vat setup allowed the part to be easily removed and rinsed, and different photocrosslinkable solutions to be easily removed and added to the vat. Two photocrosslinkable hydrogel biopolymers, poly(ethylene glycol) dimethacrylate (PEG-dma, MW 1000) and poly(ethylene glycol) diacrylate (PEG-da, MW 3400), were used as the primary scaffold materials. Multi-material scaffolds were fabricated by including controlled concentrations of fluorescently labeled dextran, fluorescently labeled bioactive PEG or bioactive PEG in different regions of the scaffold. The presence of the fluorescent component in specific regions of the scaffold was analyzed with fluorescent microscopy, while human dermal fibroblast cells were seeded on top of the fabricated scaffolds with selective bioactivity and phase contrast microscopy images were used to show specific localization of cells in the regions patterned with bioactive PEG. Multi-material spatial control was successfully demonstrated in features down to 500 microm. In addition, the equilibrium swelling behavior of the two biopolymers after SL fabrication was determined and used to design constructs with the specified dimensions at the swollen state. The use of multi-material SL and the relative ease of conjugating different bioactive ligands or growth factors to PEG allows for the fabrication of tailored three-dimensional constructs with specified spatially controlled bioactivity.
在组织工程中，控制支架的空间、机械、时间和生化结构仍然存在挑战。本工作探索了立体光刻（SL）在制造多材料空间控制生物活性支架方面的独特能力。为了实现多材料构建，设计了一个迷你罐装置，允许在制造过程中进行自对准的 X-Y 配准。迷你罐装置允许轻松地将零件取出并冲洗，并且可以轻松地将不同的光交联溶液取出并添加到罐中。使用两种光交联水凝胶生物聚合物，聚乙二醇二甲基丙烯酸酯（PEG-dma，MW 1000）和聚乙二醇二丙烯酸酯（PEG-da，MW 3400）作为主要支架材料。通过在支架的不同区域包含受控浓度的荧光标记葡聚糖、荧光标记生物活性 PEG 或生物活性 PEG 来制造多材料支架。通过荧光显微镜分析支架特定区域中荧光成分的存在，而将人真皮成纤维细胞接种在制造的支架顶部，并用选择性生物活性和相差显微镜图像显示在具有生物活性 PEG 的图案化区域中细胞的特定定位。成功地在 500 微米以下的特征中展示了多材料空间控制。此外，还确定了 SL 制造后两种生物聚合物的平衡溶胀行为，并用于设计在肿胀状态下具有指定尺寸的构建体。多材料 SL 的使用以及将不同的生物活性配体或生长因子相对容易地偶联到 PEG 的能力允许制造具有指定空间控制生物活性的定制三维构建体。
