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2017 TERMIS - Americas Conference & Exhibition Charlotte, NC December 3-6, 2017.

Three-dimensional (3D) bioprinting is driving major innovations in cartilage tissue engineering. Extrusionbased 3D bioprinting requires a phase change from a liquid hydrogel to a semi-solid crosslinked network. The hardening of the hydrogel can be achieved by a photoinitiated free radical polymerization that is highly efficient but generates cytotoxicity. Thus, we aimed to define the conditions to match cell viability with stiffness and rapid photocrosslinking that can be exploited for intra-surgical application. We have previously developed a handheld bioprinter for in situ anatomic application, “Biopen” (1, 2), that is customized in the present work for the co-axial extrusion of a stem cell niche in a noncrosslinked Core, while the photocrosslinking procedure is segregated in the stiff outer Shell. Confocal imaging was used to characterize the Core/Shell organization of a gelatinmethacrylamide/hyaluronic acid-methacrylate (GelMA/HAMa) bioscaffold and a stiffness of 200KPa was reached in only 10 seconds of UV photocuring with a selected photoinitiator. The bioprinted Adipose Derived Stem Cells maintained 90% viability after bioprinting exerting a 30% increase in cell number in only 10 days. Our Core/Shell 3D bioprinting couples the rapid generation of high modulus bioscaffold with cell survival, resulting ideal for cartilage engineering surgical techniques.