Research

Biomechanical Properties of Bone

From Hernandez and Keaveny 2006

From Hernandez and Keaveny 2006

The Hernandez Research Group are experts in the biomechanics and mechanobiology of bone.  The long-term goal of our research in bone is to understand how bone disease influences bone mechanical performance and fracture risk.   So far we have concentrated our efforts on understanding changes in bone microstructure and mechanical behavior associated with osteoporosis. The ability of a whole bone to resist fracture is determined by characteristics of bone tissue material properties and morphology (Figure on right).

 

The Hernandez Research Group concentrates on cancellous bone.  Cancellous bone is sometimes referred to as “spongy bone” and is a major structural component in regions of the skeleton that are prone to fracture in the elderly.  Recently the Hernandez Research Group found that bone remodeling, the process of removing and replacing old and damaged bone from the body, can contribute to mechanical failure of bone. Technical skills used by the Hernandez Research Group when examining bone include materials testing, image processing and analysis, finite element modeling, histology and animal experimentation.

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Serial milling collects images of the bone surface using three different fluorescent channels. We then tile and stack the cross-sections to achieve three-dimensional images of bone and microdamage (top right) or bone formation markers (bottom right).

 

JBMR_27(2) COVER4-1.indd     CoverFinal-Cropped     Bone 57(1) Cover-small   

The Hernandez Research Group was featured on the covers of the Journal of Bone and Mineral Research and BONE.

Musculoskeletal Mechanobiology and the Microbiome

Musculoskeletal tissues adapt to mechanical forces generated by locomotion during growth as well as in adulthood. The Hernandez Research Group is studying interactions between mechanical forces and systemic inflammation caused by alterations in the gut microbiota. In one arm of this work we are determining the relationship between mechanical stress and strain within cancellous bone tissue and local regions of bone formation. In a second arm of this work we are studying how alterations in the gut microbiota associated with systemic inflammation interact with physical forces to result in the development of osteoarthritis. Work in this line of investigation includes animal models, imaging and microbiology.

RatTailModel    StressBoneFormation

Biomechanics and Mechanobiology of Bacteria

The Hernandez Research Group has developed novel microfluidic devices for determining the stiffness of individual bacteria and assessing the material properties of bacterial structures (cell wall, etc.). In many instances bacteria cause infection by slipping through very small channels in the epithelium or within structures in bones or other tissues, suggesting that the ability of bacteria to deform is associated with virulence. We are using microfluidic devices to define bacterial stiffness phenotypes and their association with infection and antibiotic resistance. Additionally we are using super-resolution microscopy to determine how the stress state in the cell influences the motion of membrane proteins and leads to antibiotic resistance.

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