Microtubular architecture of biodegradable polymer scaffolds.

It is a relatively new approach to generate tissues with mammalian cells and scaffolds (temporary synthetic extracellular matrices). Many tissues, such as nerve, muscle, tendon, ligament, blood vessel, bone, and teeth, have tubular or fibrous bundle architectures and anisotropic properties. In this work, we have designed and fabricated highly porous scaffolds from biodegradable polymers with a novel phase-separation technique to generate controllable parallel array of microtubular architecture. Porosity as high as 97% has been achieved. The porosity, diameter of the microtubules, the tubular morphology, and their orientation are controlled by the polymer concentration, solvent system, and temperature gradient. The mechanical properties of these scaffolds are anisotropic. Osteoprogenitor cells are seeded in these three-dimensional scaffolds and cultured in vitro. The cell distribution and the neo-tissue organization are guided by the microtubular architecture. The fabrication technique can be applied to a variety of polymers, therefore the degradation rate and cell--matrix interactions can be controlled by the chemical composition of the polymers and the incorporation of bioactive moieties. These microtubular scaffolds may be used to engineer a variety of tissues with anisotropic architecture and properties.