(511d) Hierarchically Patterned Microfibers Via 3D Jet Writing

Electrospinning of polymer fibers is a technique that has been in use for nearly a century, and has recently been a popular platform for creating tissue engineering scaffolds. However, the use of these fibers is quite limited due to the inability to precisely control the fiber architecture. Electrohydrodynamic (EHD) co-jetting is a method of creating compartmentalized polymer fibers which allows multiple surface chemistries, mechanical properties, polymer degradation, or drug loadings to be confined into separate continuous compartments in a single fiber. Utilization of EHD co-jetting combined with a newly developed method for patterning polymer fibers via an ultra-stabilized jet has been used to create hyper-porous polymer scaffolds of multi-compartmental fibers. The combination of multicompartmental fibers and the direct fiber writing process provides a platform for controlled anisotropy, geometries, pore sizes, surface functionalities, and mechanical gradients independently on a single 3D structure. These scaffolds provide a platform technology that can be used to modulate multiple parameters simultaneously and repeatedly to more accurately recapitulate a cell's native environment. To demonstrate the fiber scaffolds can produce viable engineered tissues, the scaffolds were used to culture human mesenchymal stem cells (hMSCs) into thick tissue-like sheets. The hMSCs were subsequently osteogenically differentiated, and were implanted into a calvarial defect in nude mice for eight weeks. This system was able to generate new bone across a 3 mm defect in the mouse's skull using differentiated hMSCs grown on the fiber scaffolds.