2, The University of New Mexico, Albuquerque, New Mexico, United States
3, The University of New Mexico, Albuquerque, New Mexico, United States
4, The University of New Mexico, Albuquerque, New Mexico, United States
3D bioprinting has been introduced as a viable additive manufacturing technique for tissue engineering applications because it allows for patient-specific reconstruction of damaged hard and soft tissue. It is a desirable option because it allows for the ability to optimize bioinks to target specific tissue types and the potential to encapsulate cells in the bioinks for full-scaffold cell integration. A current limitation to bioprinting, as with most 3D printing, is that the printed material has poor tensile characteristics. Electrospinning, an alternative deposition technique, has been show to produce high tensile scaffolds for ligament tissue engineering. These densely packed structures form a favorable microenvironment that directs cell growth, migration, and proliferation. We hypothesized that a custom built 3D bioprinter + electrospinner hybrid system would allow for targeted scaffolds of the bone-ligament interface such that the 3D bioprinter would allow, with custom bioinks and optimized architecture, for a functionally-graded transition from bone to ligament phases and the E-spun fibers would allow for high tensile loading needed for the ligament phase.
We introduce a custom hybrid 3D bioprinter + electrospinner built in our lab, known as the E-spin Printer, to facilitate layer-by-layer, alternating bioprinting and electrospinning of bioink and fibers, respectively. This biocomposite scaffold is fabricated such that the tensile stiffness and strength better approximates that of native bone and ligament tissue with a functionally-graded transition from bone to ligament phases. Our bone phase is made from Polyethylene (glycol) Diacrylate (PEGDA)-based bioink, composed of PEGDA solution incorporating decellularized bone tissue to enhance the rheological and mechanical properties. The ligament phase is made from Polycaprolactone (PCL) fibers which enhance the structural integrity of the scaffold. We report preliminary findings of scaffold mechanical testing and cell viability.