(684e) Micrometer Scale Guidance of Mesenchymal Stem Cells to Form Structurally Oriented Cartilage Extracellular Matrix

Tissue engineering is viewed as a promising method for long-term repair of cartilage lesions, but current tissue engineered cartilage constructs have inferior mechanical strength compared to native articular cartilage. Other researchers attribute this problem to a lack of an oriented structure in the constructs at the microscale that is present in the native tissue. The goal of this project is to test the hypothesis that microscale features on the substrate will cause the differentiating mesenchymal stem cells (MSCs) to preferentially arrange themselves and to create an oriented extracellular matrix (ECM) on the microscale. To verify this hypothesis, stable channels of varying microscale dimensions were formed in collagen?based membranes using a combination of microfabrication and collagen soft-lithography techniques. Through image analysis, the membrane channel quality was confirmed. By modifying the plateau regions of the patterned membranes with protein resistant triblock copolymer Pluronic F108, selective attachment of human MSCs within the channels was ensured. To verify that the substrate can be used for MSC-chondrogenesis, human MSCs were seeded in these channels, and fluorescent imaging was used to confirm cell attachment within the channels. In addition, Live/Dead® staining was used to show that the MSCs attached to the membranes were highly viable. In future experiments, the chondrogenic potential of MSCs seeded in these channels will be investigated by evaluating them through histology and immunochemistry. Through mechanical strength testing and transmission electron microscopy imaging of the ECM produced, the ability of these channels to facilitate the creation of an oriented ECM at the microscale will be determined.