Date of Award

Fall 11-2021

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical Engineering

First Advisor

David K. Mills

Abstract

Fractures and segmental bone defects are the primary cause of patient morbidity and brings a substantial economic burden to the healthcare system. Bone grafts used for bone injuries, tumors, and other pathologies related to poor fracture healing in the United States cost considerable money each year. The total cost of treating bone defects is about 5 billion US dollars. Autologous bone transplantation is the ideal method for the treatment of bone defects. However, their clinical results are variable and increase postoperative morbidity (especially at the donor site) and surgical costs. To circumvent these limitations, tissue engineering and cell-based therapies have been proposed as alternative methods to induce and promote bone repair.

In this study, we have developed a composite photo-crosslinked hydrogel with favorable mechanical properties and tunable bioactive properties. Furthermore, this composite hydrogel system, when combined with 3D printed scaffolds, can be modified to meet various applications for bone tissue regeneration applications. In this study, we identified the optimal combination between different concentrations of halloysite nanotubes (HNTs), strontium coated HNTs (SrHNTs), bone morphogenetic protein 2 (BMP-2), collagen methacrylated (COMA), and cross-linking time to develop a suitable scaffold. The scaffold is biocompatible and biodegradable, but also antibacterial and should promote faster healing.

The results suggest that gentamicin+SrHNTs+BMP-2 COMA hydrogel combined with a polycaprolactone (PCL) scaffold provides an optimal scaffold that can match the mechanical properties of bone. The next stage is to explore the scaffolds’ application in biomedical engineering. To do this, animal testing will need to be performed. If the scaffold works in the animal model it will provide a meaningful treatment plan for bone tissue repair and regeneration.

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