Research

Y. Zhou, M. Kastner, T. Tighe, J. Du, Elastic Properties of Bovine Cortical Bone from Micro- to Nano- Scales as Measured by PeakForce Tapping Atomic Force Microscopy, (2020), Extreme Mechanics Letters, 41, 101031.

DOI: 10.1016/j.eml.2020.101031 Link

Bone is a composite material consisting of organic and inorganic components that are organized into hierarchical structures to provide load-bearing functions. This paper presents the results of PeakForce Tapping atomic force microscopy (AFM) scans on cut and polished bovine cortical bone specimens that were submerged in water. The elastic modulus map and surface morphology were obtained for various bone hierarchical structures from submillimeter- to submicron-scales.

Y. Zhou, J. Dang, Y. Chen, S. Zheng, J. Du, Microstructure and Mechanical Behaviors of Tibia for Collagen Induced Arthritic Mice Treated with Gingiva-Derived Mesenchymal Stem Cells, (2021), Journal of the Mechanical Behavior of Biomedical Materials, DOI: 10.1016/j.jmbbm.2021.104719 Link

Rheumatoid arthritis (RA) is a systemic polyarticular arthritis that primarily affects the small joints but also causes bone erosion in large joints. None of the currently existing treatment approaches is curable. In this study, the effects of human gingiva-derived mesenchymal stem cells (GMSCs) on collagen-induced arthritis (CIA) mice are examined by experimentally assessing the microstructure and mechanical behaviors of tibia. The results show that CIA disease caused bone erosion in epiphyseal cortical bone and weakened the load-bearing function of proximal tibia. GMSC treatment interfered with the progress of CIA, attenuated the bone erosion in epiphyseal and metaphyseal trabecular bone, and resulted in improved load-bearing function of proximal tibia. GMSCs provide a promising potential treatment of autoimmune arthritis.

Y. Zhou, C. Gong, G. S. Lewis, A. D. Armstrong, J. Du, 3D full-field biomechanical testing of a glenoid before and after implant placement, (2020), Extreme Mechanics Letters, 35,100614. DOI: 10.1016/j.eml.2019.100614 Link

Loosening of the glenoid component is the most common cause of failure of total shoulder arthroplasty. While the underlying mechanisms are not fully understood, mechanical factors are widely reported to play a key role in glenoid component loosening. Under the same eccentric loading conditions, implanted glenoid exhibited a wider range of strain, because the placement of glenoid component increases the bending moment inside the glenoid. This proof-of-concept study provides a feasible and powerful method for the study of 3D full-field biomechanics in native and implanted glenoids.

K. Su, Y. Zhou, M. Hossaini-Zadeh, J. Du, Effects of implant buccal distance on peri-implant strain: A micro-CT based finite element analysis, (2021), Journal of the Mechanical Behavior of Biomedical Materials, 116:104325.

PMID: 33485035 Link

Q. Mao, K. Su, Y. Zhou, M. Hossaini-Zadeh, G. Lewis, J. Du, Voxel-based micro-finite element analysis of dental implants in a human cadaveric mandible: Tissue modulus assignment and sensitivity analyses, (2019), Journal of the Mechanical Behavior of Biomedical Materials, 94:229-237. PMID: 30925312 Link

Bone-implant mechanics is one of the factors that contribute to implant stability and success. In this work, voxel-based finite element models were built based on the micro-CT images of human cadaveric mandible specimens before and after implant placement. The average values of maximum principal strain in the buccal and lingual ROIs were in good agreement with those measured using mechanical testing coupled with micro-CT and digital volume correlation. Then the implant position was virtually changed in the models to be placed lingually or buccally. The computed strain in the buccal bone decreased when the implant was placed away from the buccal plate. The results indicate that the distance from the implant to the buccal plate can affect the mechanical stimuli in bone, especially in the buccal plate, which may subsequently affect the bone remodeling process and buccal bone resorption.

J. Hu, Y. Zhou, J. D. Obayemi, J. Du, W. O. Soboyejo, An investigation of the viscoelastic properties and the actin cytoskeletal structure of triple negative breast cancer cells, (2018), Journal of the Mechanical Behavior of Biomedical Materials, 86:1-13. PMID: 29913305 Link

Y. Jiang, Y. Zhou, X. Bao, C. Chen, L. Randolph, J. Du, X. Lian, An ultrasensitive calcium reporter system via CRISPR-Cas9 mediated genome editing in human pluripotent stem cells, (2018), iScience, 9:27-35. PMID: 30368079 Link

Digital image correlation (DIC), a 2D strain mapping method, was applied to compare the viscoelastic properties of normal/metastatic cells and to correlate periodic calcium intensity variation with shear strain caused by stem cell contraction.