Integrating Non-Viral Gene Therapy and 3D Bioprinting for Bone, Cartilage and Osteochondral Tissue Engineering

The repair of osteochondral defects, affecting both the articular cartilage and the underlying subchondral bone, is key for the effective recovery of joint homeostasis and the prevention of further cartilage degeneration and the onset of osteoarthritis (OA). Although important advances have been made in the field of tissue engineering to regenerate these injuries, the traditional approaches based on the formation of homogenous tissues fail to recapitulate the spatial complexity of the osteochondral unit. The objective of this thesis was to engineer a multiphasic tissue suitable for osteochondral defect regeneration by combining 3D bioprinting and non-viral gene delivery to spatially regulate the differentiation of mesenchymal stem cells (MSCs). Realising this objective first required (1) optimisation of the non-viral gene delivery vector, (2) the identification of suitable therapeutic gene combinations to direct MSC differentiation and (3) the development of printable biomaterials, also known as bioinks, which were supportive of non-viral gene delivery both in vitro and in vivo. These gene activated bioinks were capable of spatially directing MSC fate towards either the osteogenic or chondrogenic pathway. In turn, this enabled the printing of mechanically robust biphasic osteochondral constructs with zonally confined gene delivery and spatially defined stem cell differentiation and matrix deposition. In vivo, these printed constructs promoted the development of tissue mimicking key aspects of the osteochondral unit. In conclusion, this thesis highlights a promising and novel approach for the incorporation of gene delivery for 3D bioprinting ande engineering of therapeutically relevant and structurally complex musculoskeletal tissues.

Year	Entry
2007	Oest ME, Dupont KM, Kong H, Mooney DJ, Guldberg RE. Quantitative assessment of scaffold and growth factor‐mediated repair of critically sized bone defects. J Orthop Res. July 2007;25(7):941-950.
2004	McBeath R, Pirone DM, Nelson CM, Bhadriraju K, Chen CS. Cell shape, cytoskeletal tension, and RhoA regulate stem cell lineage commitment. Dev Cell. April 2004;6(4):483-495.
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2003	Gerstenfeld LC, Cullinane DM, Barnes GL, Graves DT, Einhorn TA. Fracture healing as a post‐natal developmental process: molecular, spatial, and temporal aspects of its regulation. J Cell Biochem. April 2003;88(5):873-884.
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Year

Entry

2007

Oest ME, Dupont KM, Kong H, Mooney DJ, Guldberg RE. Quantitative assessment of scaffold and growth factor‐mediated repair of critically sized bone defects. J Orthop Res. July 2007;25(7):941-950.

2004

McBeath R, Pirone DM, Nelson CM, Bhadriraju K, Chen CS. Cell shape, cytoskeletal tension, and RhoA regulate stem cell lineage commitment. Dev Cell. April 2004;6(4):483-495.

1998

Yoo JU, Barthel TS, Nishimura K, Solchaga L, Caplan AI, Goldberg VM, Johnstone B. The chondrogenic potential of human bone-marrow-derived mesenchymal progenitor cells. J Bone Joint Surg. December 1998;80A(12):1745-1757.

2003

Gerstenfeld LC, Cullinane DM, Barnes GL, Graves DT, Einhorn TA. Fracture healing as a post‐natal developmental process: molecular, spatial, and temporal aspects of its regulation. J Cell Biochem. April 2003;88(5):873-884.

2004

Simmons CA, Alsberg E, Hsiong S, Kim WJ, Mooney DJ. Dual growth factor delivery and controlled scaffold degradation enhance in vivo bone formation by transplanted bone marrow stromal cells. Bone. August 2004;35(2):562-569.