Imaging hydroxyapatite-based materials via piezoresponse force microscopy

Abstract

Hydroxyapatite (HAp), the main constituent of the rigid cortical bone, is a material that exhibits enhanced osteoconduction at its surface. Although its high electrical functionality has been long associated with its large surface charge density, the exact physical nature of the charge has long remained an enigma. In the first part of this thesis, we will go extensively over the theoretical aspect of the measurement tools used in this research, such as piezoresponse force microscopy (PFM), to discuss its usage in the analysis of the electromechanical response observed at the material surface. Subsequently, we focus on discerning the physicochemical origin of the PFM response observed at the HAp surface for assessing the contribution of the various electrical properties of HAp in the osteointegration of synthetic HAp sintered at a high temperature range. Finally, having identified the nature of the material properties of HAp, we introduce a preliminary step we took in synthesizing a new class of nanocomposite thin film that is viable in biomedical applications, where we modified the surface of the HAp for its inclusion in a polymer matrix. This research will provide the reader with a comprehensive understanding of the dynamics and electrostatics of PFM and its application in analyzing the surface properties of electrically function materials like HAp.