Development of High Strength, Rapidly Degradable Bone Composites for Treatment of Osteoporosis
Open Access
- Author:
- Smith, Jessica
- Area of Honors:
- Biochemistry and Molecular Biology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Jian Yang, Thesis Supervisor
Ying Gu, Thesis Honors Advisor - Keywords:
- biomaterials
citrate
osteoporosis
orthopedics
orthopedic materials
orthopedic fractures
POC
biomedical engineering
material science
bioengineering
xylitol - Abstract:
- One of the most common causes of fractures in the adult population is osteoporosis, affecting 200 million people worldwide. Osteoporosis is a systemic metabolic disease characterized by decreased bone strength and increased fracture risk due to deterioration of the bone structure via calcium loss, increased oxidative stress, and excessive bone resorption (1). According to the World Health Organization, one-third of white women over the age of 65 are affected by osteoporosis. Osteoporotic fractures have a 50% mortality rate (2). Treating osteoporotic fractures is difficult due to the complex organic/inorganic architecture of orthopedic tissue. Additionally, osteoporotic bone has decreased mechanical strength and increased porosity, and treatments are needed to address the complexity of the shapes and structural defects of osteoporotic fractures. Biomaterials offer a solution for osteoporotic fractures. Poly(octamethylene citrate) (POC) is a citrate-based biomaterial that is biocompatible with bone and shows increased mechanical strength to other biomaterials. However, POC has a long degradation rate compared to natural bone regrowth rates, and the mechanical strength of POC is lower than cortical bone. Incorporating xylitol into POC is hypothesized to increase the mechanical strength of bone while also increasing the rate of degradation. Additionally, xylitol may also increase the biocompatibility of the biomaterial as it has been shown to inhibit osteoclastogenesis, a process that is increased in osteoporosis. It was found that increasing rates of xylitol in POC formulations increased the mechanical strength, density, hydrophilicity, and fluorescence of the POC films. Xylitol in POC/Hydroxyapatite (HA) composites also increased the mechanical strength. Increasing xylitol in the composites led to increased degradation rates while maintaining biological pH. Incorporating the chemical crosslinker hexamethylene diisocyanate (HDI) into POC/HA composites containing xylitol resulted in self-setting materials with minimal dimension shrinkage and promising mechanical strength.