Keywords: biomaterials, nanofiber
Summary:The ability of polymer nanofibers to direct cell alignment, migration, differentiation, and ECM production as physical guidance cues is well established. However, delicate nanofiber materials are difficult to assemble into sparse architectures that allow space for cell infiltration. Thus, most attempts to construct 3D grafts involve rolling or stacking thick, densely packed aligned nanofiber substrates that prevent infiltration and limit direct cell-nanofiber contacts. This talk will describe a layer-by-layer additive manufacturing approach used to fabricate hydrogel-nanofiber composite materials. An automated track collecting device enables the construction of low density aligned nanofiber arrays that are dip coated in hydrogel solution to form thin composite films. Then the films are combined into a cohesive 3D structure using a layer-by-layer process that leverages the thermoreversible gelation properties of gelatin methacrylate. The degradable hydrogel component serves to support a sparse 3D aligned nanofiber architecture, while allowing cell infiltration through the protease degradable matrix. Additional processes have been developed to engineer surface modifications, drug loading and enhanced mechanical strength into the embedded nanofibers. These composite scaffolds have properties that are suitable for regenerating aligned soft tissues such as nerve and muscle.