Singh Milind, Morris Casey P, Ellis Ryan J, Detamore Michael S, Berkland Cory
Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas 66047, USA.
Tissue Eng Part C Methods. 2008 Dec;14(4):299-309. doi: 10.1089/ten.tec.2008.0167.
Spatial and temporal control of bioactive signals in three-dimensional (3D) tissue engineering scaffolds is greatly desired. Coupled together, these attributes may mimic and maintain complex signal patterns, such as those observed during axonal regeneration or neovascularization. Seamless polymer constructs may provide a route to achieve spatial control of signal distribution. In this study, a novel microparticle-based scaffold fabrication technique is introduced as a method to create 3D scaffolds with spatial control over model dyes using uniform poly(D,L-lactide-co-glycolide) microspheres. Uniform microspheres were produced using the Precision Particle Fabrication technique. Scaffolds were assembled by flowing microsphere suspensions into a cylindrical glass mold, and then microspheres were physically attached to form a continuous scaffold using ethanol treatment. An ethanol soak of 1 h was found to be optimum for improved mechanical characteristics. Morphological and physical characterization of the scaffolds revealed that microsphere matrices were porous (41.1 +/- 2.1%) and well connected, and their compressive stiffness ranged from 142 to 306 kPa. Culturing chondrocytes on the scaffolds revealed the compatibility of these substrates with cell attachment and viability. In addition, bilayered, multilayered, and gradient scaffolds were fabricated, exhibiting excellent spatial control and resolution. Such novel scaffolds can serve as sustained delivery devices of heterogeneous signals in a continuous and seamless manner, and may be particularly useful in future interfacial tissue engineering investigations.
三维（3D）组织工程支架中生物活性信号的时空控制是人们非常渴望实现的。将这些特性结合在一起，可以模拟和维持复杂的信号模式，比如在轴突再生或新血管形成过程中观察到的那些模式。无缝聚合物构建体可能提供一种实现信号分布空间控制的途径。在本研究中，引入了一种基于微粒的新型支架制造技术，作为一种利用均匀的聚（D，L - 丙交酯 - 乙交酯）微球来创建对模型染料具有空间控制能力的3D支架的方法。使用精密颗粒制造技术制备均匀的微球。通过将微球悬浮液流入圆柱形玻璃模具中来组装支架，然后使用乙醇处理使微球物理附着以形成连续的支架。发现1小时的乙醇浸泡对于改善机械特性是最佳的。支架的形态和物理表征表明，微球基质是多孔的（41.1 +/- 2.1%）且连接良好，其压缩刚度范围为142至306 kPa。在支架上培养软骨细胞表明这些基质与细胞附着和活力具有相容性。此外，还制造了双层、多层和梯度支架，展示出优异的空间控制和分辨率。这种新型支架可以作为异质信号的持续递送装置，以连续和无缝的方式发挥作用，并且在未来的界面组织工程研究中可能特别有用。
