Nanoscale Characterization of Bone Tissue under a Precise Displacement Control Using Atomic Force Microscopy

Abstract

The bone is an indispensable structure in the skeletal system of the human body that provides a mechanical function to bear various loadings. In a healthy person or animal, bone remodels its composition and arrangement of the constituent materials to adapt to changing functional demands continuously throughout life [1]. However, the mechanism of how the force input to the bone is transduced to be involved in the physiological bone buildup process has not been clearly understood. In order to uncover the mechanism, this project aims to investigate the changes in the morphology and properties of bone in response to an external loading stimuli using Atomic Force Microscopy (AFM). To achieve this goal, a precise displacement control is integrated into an existing AFM setup. A piezoelectric motor with a nanometer-scale resolution provides a precise control of force and displacement while the force load data is acquired by an axial tension load cell integrated in the stage. The successful integration of the force and displacement control into AFM enables to image the bone sample with the nanometer-scale resolution when a precisely controlled force is applied to the bone sample. The nanoscale morphology change of a human mandible bone sample is characterized while the strain of the sample valued between 0 and 0.001.