A micro-mold based technique for the synthesis of scaffold-free, single tendon fibers

There is a growing clinical demand for the development of replacement constructs that can emulate native tendon tissue. In this study, a technique to synthesize scaffold-free, single tendon fibers using micro-molded channels is presented. This mold-based channel fabrication technique replaces our previously established laser-based technique, to provide greatly improved reproducibility in 3D channel geometries, as well as increased throughput in channel fabrication. Herein, we utilize a custom-fabricated micro-mold to create growth channels, and explore the influence of UV crosslinking, cell-seeding density and graded cellular loading, on fiber formation and integration. Loading the channels with a cell-density gradient, and using a higher cell-seeding density, worked synergistically to promote fiber formation and integration into collagen “anchors”. This new technique allows rapid and consistent fabrication of single-fiber growth channels and effectively directs cells to form fibers by cellular self-assembly. Due to the high cellularity, direct cell-cell contact, and scaffold-free nature of this technique, this platform provides a model of fiber development, rather than one of remodeling. This allows for future study of the influence of mechanical stimulation (e.g., cyclic strain) and application of select growth factors, on the structure and function of developing fibers.