Development and characterization of synthetic injectable biomaterials incorporated with doped calcium silicate ceramics

Abstract

Injectable biomaterials that are able to set in situ provide clinicians a valuable tool in treating patients with clinically relevant tissue defects, as these can be administered via minimally invasive procedures and able to fill complex-shaped tissue defects. Injectable biomaterials also allow for novel fabrication techniques that aid in developing complex structures that mimic biological tissue. However, clinically-used injectable biomaterials that are currently available possess critical and inherent shortcomings that are difficult to address. The aim of this thesis was to develop and characterize new synthetic injectable biomaterials to address some of these shortcomings. To achieve this aim, the works in this thesis combined two distinct strategies: (1) utilize injectable material platforms not currently established for clinical use, but proven to be biocompatible and exhibit promising properties for filling musculoskeletal tissue defects; and (2) further improve the physicochemical and biological properties of these injectable materials, by incorporating bioactive doped calcium silicate ceramics. In particular, this thesis focused on the development and characterization of three such novel injectable biomaterials: (1) thermoplastic polycaprolactone composited with baghdadite (Ca3ZrSi2O9); (2) strontium-hardystonite (Sr-Ca2ZnSi2O7, Sr-HT)-phosphate cement; and (3) self-setting polyvinyl alcohol hydrogel composited with Sr-HT. All the synthetic injectable materials developed in this thesis possess sets of simultaneous ideal physicochemical and biological properties that address the limitations of injectable biomaterials currently established in the clinical setting. This thesis demonstrates that the physicochemical and biological properties of various injectable material platforms can be improved significantly by incorporating DCSC such as baghdadite and Sr-HT in order to render these materials ideal for filling various musculoskeletal tissue defects.