Monday  |  Salon 8  |  10:00 AM–10:20 AM

#15869, Experimental Methodology for in-Vitro Mineralization and Tensile Testing of Single Collagen Fibrils

Mineralized collagen fibrils are natural composites comprising tropocollagen molecules and hydroxyapatite (HAP) minerals that form the basic hierarchical structural unit of collagenous tissues. Although the viscoelastic mechanical response of individual unmineralized collagen fibrils is reasonably well understood, there is no experimental evidence of their mineralized form. In this work, in-vitro tensile experiments with individual mineralized collagen fibrils were performed to understand the governing deformation mechanisms. The mineralized collagen fibrils were reconstituted from Type I calf skin collagen and biosynthetically mineralized with HAP crystals with the aid of poly l-aspartic acid. A Microelectromechanical Systems (MEMS) based methodology, coupled with edge detection, developed in our lab was implemented to perform experiments on fully hydrated mineralized collagen fibrils. The edge detection method utilizes high magnification optical images to obtain nanometer-level displacement resolution, which, in turn, was used along with closed-loop real-time feedback control to maintain constant force or extension to nanometer-scale mineralized collagen fibrils.

Kathiresan Karunakaran   University of Illinois Urbana-Champaign
Ioannis Chasiotis   University of Illinois Urbana-Champaign