(482.19) Mechanical Properties of Embryonic Mouse Cartilage and Bone

Poster Board Number: C134
Introduction: AAA has separate poster presentation times for odd and even posters.
Odd poster #s – 10:15 am – 11:15 am
Even poster #s – 11:15 am – 12:15 pm

Julian Gifford-Mahany (The Pennsylvania State University), Sarah Kiemle (The Pennsylvania State University), Mizuho Kawasaki (The Pennsylvania State University), Timothy Tighe (The Pennsylvania State University), Kazuhiko Kawasaki (The Pennsylvania State University), Joan Richtsmeier (The Pennsylvania State University)

Differences in material characteristics of cartilage and bone are primarily known through investigation of postnatal specimens but the mechanical properties of these tissue during embryogenesis are less well studied. Importantly, embryonic cartilage and bone have not been tested extensively in aqueous environments, limiting the validity of previous investigations. The purpose of this project is to characterize the stiffness and strength of embryonic cranial bone and cartilage using atomic force microscopy (AFM). We test the hypothesis that embryonic cartilage is stronger than embryonic bone against the null hypothesis that embryonic tissue response will be comparable to adult tissue in which bone is the stronger of the two tissues. In vivo conditions are simulated by immersing tissues in room-temperature phosphate-buffered saline before and during testing. Data are acquired using calibrated AFM probes which yield quantitative and qualitative data. Force-distance curves include data on topography, adhesion, and DMTModulus, the latter of which can be transformed into Young’s Modulus through models which approximate the shape of the AFM probe, including the Sneddon model. Calcified tissue intended for testing is verified on the micro scale using AFM topography and on the macro scale using calcein dye. Each 2 square micron topographical image is accompanied by 16,384 force versus distance curves which yield a value for modulus of elasticity. Data show DMTModulus values ranging from approximately 200 kPa to 7.7 MPa for embryonic cartilage and 120 kPa to 3.0 MPa for embryonic bone providing preliminary data indicating that cartilage varies more than bone and may be significantly stronger than bone in mouse embryos.

This work is supported in part by NIH/NIDCR grant R01DE027677