Adapting to Cracks: Learning from the Dynamic Structure of Mineralized Tissues and Cells

Abstract 

Biogenic materials such as bone exhibit a combination of properties exceeding that of their constituents, a feat generally credited to their hierarchical structure, down to the nanoscale, where mineralized collagen fibrils act as the mechanical building blocks. Because of this inherent nanometer scale, we have limited knowledge of bone’s time-dependent and small-scale response to physiological loading. During cyclic loading, injury, and repair, bone tissue is exposed to large strains and dynamic loads, a drastic departure from the quasi-static, macroscale conditions on which our current knowledge of bone fracture is based. Here, we will use in situ electron and X-ray nanomechanical experiments to ask: How does the nanostructure of bone respond to cyclic physiological loading? What mechanisms dictate dynamic fracture? And how do the cells embedded in bone sense and respond to these dynamic changes? Finally, we will show how nano and metal additive manufacturing let us both probe these questions and translate bone’s design principles into fatigue-resistant synthetic materials.

About the Speaker 

Ottman Tertuliano is the AMA Family Assistant Professor in Mechanical Engineering and Applied Mechanics (MEAM) at Penn, where he leads research exploring how mechanical forces shape both natural tissues and engineered materials. By uncovering how physiological loads influence tissue health and resilience, his group designs synthetic systems with similar adaptability—structural materials that adapt and endure under changing demands. Ottman’s group leverages this bio-inspired approach to develop biocompatible materials that guide cellular behavior while advancing additive manufacturing for synthetic materials that achieve improved “material health” over time. Ottman earned his B.S. in Mechanical Engineering from Columbia University in 2013 and a Ph.D. in Materials Science from Caltech in 2018, where he specialized in nanoscale studies of bone mechanics and fracture. Before joining Penn in 2022, he was the inaugural Stephen Timoshenko Distinguished Postdoctoral Fellow at Stanford University, where he advanced techniques for additive manufacturing of high-conductivity and refractory metals. In 2024, he received the NSF CAREER Award for his work using synchrotron X-rays to reveal how tissue microstructures adapt to repeated and traumatic mechanical loads.

Host: Professor Callan Luetkemeyer