H. Jang, J. Kwon, M. Cline, M. Reilly, H. Cho
The Ohio State University,
United States
Keywords: AFM, PFM, collagen piezoelectricity, bone quality, lens capsule
Summary:
Atomic force microscopy (AFM) has served as a cornerstone technique for nanoscale characterization since its introduction in the 1980s, enabling imaging and property quantification with nanometer spatial resolution under a wide range of environmental conditions. By leveraging a deep understanding of cantilever mechanics and detection strategies, our research group has advanced AFM toward the quantitative probing of multi-physical material responses, including electromechanical coupling and spatially localized mechanical heterogeneity. In particular, we have developed a customized cantilever platform and refined measurement protocols that enhance sensitivity to piezoelectric and mechanical properties in various materials. In this talk, I will demonstrate how these AFM innovations enable new insights into the structure–function relationships of biomaterials. First, I will present our discovery of collagen fibril piezoelectricity and its nanoscale periodic heterogeneity, revealed through Piezoresponse Force Microscopy, and discuss its implications for intrafibrillar mineralization and bone stiffness regulation. Second, I will show age-dependent nanomechanical variations in cortical bone tissue, elucidating how localized stiffening and structural remodeling contribute to bone quality over time. Finally, I will present AFM-based force spectroscopy data on the porcine lens capsule, where regional differences in Young’s modulus between the anterior and posterior surfaces were measured under fully hydrated conditions. Together, these studies demonstrate how carefully calibrated AFM techniques can reveal multi-physical characteristics in biomaterials that are otherwise difficult to detect, supporting a quantitative understanding of structure–property relationships across biological length scales.