PhD Thesis Defense: Peter Bertone

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"The Effects of Ionizing Radiation on Biomaterial Mediated Healing of Bone"

Abstract

Reconstruction of bone defects after cancer resection is complicated by radiotherapy (RTx), which impairs bone healing and limits bone grafting effectivity. Engineered bone graft substitutes offer an alternative but have been developed almost exclusively in non-irradiated conditions. This dissertation examines how therapeutic RTx affects a biomaterial based bone-graft substitute (Chitosan-Gelatin cryogel scaffold), and the healing environment into which this material is implanted.

This work first establishes a composite scaffold combining the cryogel with a 3D-printed, sintered bio-ceramic structure to improve its physical properties and bioactivity (hydroxyapatite–wollastonite lattice). Then, to further understand RTx interaction with the polymer gel, this work characterizes the physical, chemical, and biological stability of the cryogel across a clinically relevant single-fraction dose range. Finally, this work evaluates bone healing in a mouse femoral critical defect model under single-fraction and fractionated RTx, with and without an implanted scaffold. Together, these studies probe the combined healing environment of biopolymer implants in bone after radiation treatment. 

Thesis Committee

Katherine Hixon (Chair), Douglas Van Citters, Joseph Paydarfar, Joel Boerckel (UPenn)

Contact

For more information, contact Thayer Registrar at thayer.registrar@dartmouth.edu .