http://hdl.handle.net/10379/6200 2017-10-29T22:05:35Z http://hdl.handle.net/10379/6331 Bridging the osteochondral gap in mandibular condyle reconstruction with multiphasic 3D printing Salash, J.R.; Lohfeld, Stefan; Detamore, M.S. Individuals afflicted with temporomandibular joint disorders experience a reduced ability to perform the most basic human functions such as chewing and talking. In advanced disease states, total joint replacement is often necessary to improve range of motion and minimize pain. Current surgical treatments use either autogenous grafts or alloplastic implants to replace the condyle and ramus of the mandible. Although these interventions aid in improving joint function, a tissue-engineering strategy may be useful to expand the range of treatment options and offer an approach that not only restores functionality but also facilitates regeneration of the diseased tissue [1]. Toward this objective, 3D printing technology was used to fabricate patient-specific constructs with precise osteo- and chondroinductive regions to facilitate the formation of osteochondral tissue similar to that found in the mandibular condyle. The osseous region of the scaffold was composed of polycaprolactone and hydroxyapatite nanoparticles to promote bone formation and was manufactured via fused deposition modeling, while an extrusionbased method was used to print the chondral region, which was composed of hyaluronic acid hydrogel and decellularized cartilage. Patient data were obtained from computed tomography images to create implants with correct anatomical shapes, and pore architectures were designed with solid modeling software. Future work will be performed to observe the efficacy of the implants to promote osteochondral differentiation of human bone marrow stem cells in vitro. 2015-09-01T00:00:00Z http://hdl.handle.net/10379/6330 3D Printing of Microspheres for Tissue Engineering Scaffolds Lohfeld, Stefan; Salash, J. R.; McHugh, Peter E.; Detamore, M.S. Microspheres have tremendous potential as a scaffold material for tissue engineering applications due to their capability of encapsulation and controlled release of factors that assist tissue regeneration in the desired fashion. Gradient scaffolds consisting of multiple types of microspheres can release different factors at different sites of the scaffold. Current microsphere scaffold production methods, however, cannot address the need for internal architectures to meet specific requirements in different scaffold regions, e.g., for mechanical properties or porosity. We combined 3D printing and microspheres to create scaffolds with defined internal architectures and tailored placing of materials, intended for bone/cartilage interfaces. Poly(lactic-co-glycolic acid) microspheres were mixed with alginate to create a highly viscous suspension, which was manually expressed through a syringe needle to test feasibility. Subsequently, scaffolds were fabricated using a RepRap printer equipped with a syringe extruder. Thematrix of the printedmaterial dried and hardened quickly through evaporation of water. This allowed to print a porous green body, which was then further stabilized by sintering. The amount of alginate played an important role on the suspension s viscosity and drying time to fabricate a stable construct without sagging in unsupported areas. This is the first demonstration of direct 3D printing of microsphere based scaffolds. This adds a high degree of freedom for the fabrication of such scaffolds with local definitions for mechanical properties, porosity, focal placement of phases, and controlled release of encapsulated factors. 2015-09-01T00:00:00Z