Organic-Inorganic Hybrid Biomaterials for Bone Tissue Engineering and Drug Delivery
Abstract
Bone biomaterials prepared from a combination of biodegradable polymers and bioactive glasses offer several advantages, including favorable cell interactions, selective gene expression, and delivery of biomolecules. Furthermore, the interaction of the organic and inorganic phases at the molecular level results in a single-phase hybrid material possessing synergistic properties.
This research aimed to design bone biomaterials from α-amino acid-based poly(ester amide) (PEA) and tertiary bioactive glasses using a sol-gel process. Since incorporating calcium into the bioactive glass network is challenging at sol-gel reaction temperatures, calcium ethoxide and calcium chloride were studied as precursors, and the optimum reaction conditions were identified. Mesoporous silica nanoparticles loaded with a model drug were incorporated into the hybrid biomaterials during scaffold fabrication to provide drug delivery capability. In an alternative strategy, a hydrophobic model drug was loaded to the PEA, while a hydrophilic model drug was loaded to the bioactive glass during the hybrid sol-gel microparticle synthesis. Data presented in this thesis demonstrated the feasibility of delivering multiple biomolecules from these hybrid biomaterials. Owing to the presence of the amino acid L-phenylalanine, the hybrid microparticles were fluorescent with tunable emission by changing the excitation wavelengths ranging from 300 to 565 nm for potential multiplex imaging.
The PEA-bioactive glass hybrids were cytocompatible and promoted hydroxyapatite formation from simulated body fluid. Moreover, the hybrid microparticles induced osteogenic differentiation of 10T1/2 cells as a stand-alone system without biochemical factor supplements. Taken together, the data presented in this thesis demonstrated the potential of hybrid biomaterials for bone tissue engineering applications.