title: Determination of strain-rate-dependent mechanical behavior of living and fixed osteocytes and chondrocytes using atomic force microscopy and inverse finite element analysis.
abstract: The aim of this paper is to determine the strain-rate-dependent mechanical behavior of living and fixed osteocytes and chondrocytes, in vitro. First, atomic force microscopy (AFM) was used to obtain the force-indentation curves of these single cells at four different strain-rates. These results were then employed in inverse finite element analysis (FEA) using modified standard neo-Hookean solid (MSnHS) idealization of these cells to determine their mechanical properties. In addition, a FEA model with a newly developed spring element was employed to accurately simulate AFM evaluation in this study. We report that both cytoskeleton (CSK) and intracellular fluid govern the strain-rate-dependent mechanical property of living cells whereas intracellular fluid plays a predominant role on fixed cells' behavior. In addition, through the comparisons, it can be concluded that osteocytes are stiffer than chondrocytes at all strain-rates tested indicating that the cells could be the biomarker of their tissue origin. Finally, we report that MSnHS is able to capture the strain-rate-dependent mechanical behavior of osteocyte and chondrocyte for both living and fixed cells. Therefore, we concluded that the MSnHS is a good model for exploration of mechanical deformation responses of single osteocytes and chondrocytes. This study could open a new avenue for analysis of mechanical behavior of osteocytes and chondrocytes as well as other similar types of cells.
authors: Trung Dung
authors: TD
authors: Nguyen
authors: YuanTong
authors: Y
authors: Gu
mesh_terms: D001696:Biomechanical Phenomena; D002470:Cell Survival; D018914:Cells, Immobilized / Q000166:cytology; D019902:Chondrocytes / Q000166:cytology*; D003599:Cytoskeleton; D020342:Finite Element Analysis; D006801:Humans; D018625:Microscopy, Atomic Force; D010011:Osteocytes / Q000166:cytology*; D013314:Stress, Mechanical