title: Mechanical stiffness as an improved single-cell indicator of osteoblastic human mesenchymal stem cell differentiation.
abstract: Although it has been established that cellular stiffness can change as a stem cell differentiates, the precise relationship between cell mechanics and other phenotypic properties remains unclear. Inherent cell heterogeneity and asynchronous differentiation complicate population analysis; therefore, single-cell analysis was employed to determine how changes in cell stiffness correlate with changes in molecular biomarkers during differentiation. Design of a custom gridded tissue culture dish facilitated single-cell comparisons between cell mechanics and other differentiation biomarkers by enabling sequential measurement of cell mechanics and protein biomarker expression at the single cell level. The Young's modulus of mesenchymal stem cells was shown not only to decrease during chemically-induced osteoblast differentiation, but also to correlate more closely with the day of differentiation than did the relative expression of the traditional osteoblast differentiation markers, bone sialoprotein and osteocalcin. Therefore, cell stiffness, a measurable property of individual cells, may serve as an improved indicator of single-cell osteoblast differentiation compared to traditional biological markers. Revelation of additional osteoblast differentiation indicators, such as cell stiffness, can improve identification and collection of starting cell populations, with applications to mesenchymal stem cell therapies and stem cell-based tissue engineering.
authors.affiliation: The G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Bongiorno
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA.
authors.forename: Jacob
authors.initials: J
authors.lastname: Kazlow
authors.affiliation: School of Biology, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Roman
authors.initials: R
authors.lastname: Mezencev
authors.affiliation: The Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Griffiths
authors.affiliation: School of Engineering, Virginia Commonwealth University, Richmond, VA, USA.
authors.forename: Rene
authors.initials: R
authors.lastname: Olivares-Navarrete
authors.affiliation: School of Biology, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: John F
authors.initials: JF
authors.lastname: McDonald
authors.affiliation: School of Engineering, Virginia Commonwealth University, Richmond, VA, USA.
authors.forename: Zvi
authors.initials: Z
authors.lastname: Schwartz
authors.affiliation: School of Engineering, Virginia Commonwealth University, Richmond, VA, USA.
authors.forename: Barbara D
authors.initials: BD
authors.lastname: Boyan
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; The Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA.
authors.forename: Todd C
authors.initials: TC
authors.lastname: McDevitt
authors.affiliation: The G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA; The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; The Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA. Electronic address: todd.sulchek@me.gatech.edu.
authors.forename: Todd
authors.initials: T
authors.lastname: Sulchek
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D055119:Elastic Modulus; D006801:Humans; D058574:Integrin-Binding Sialoprotein / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology; D018625:Microscopy, Atomic Force; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis; D013234:Stem Cells / Q000166:cytology; D023822:Tissue Engineering
chemical_list: D015415:Biomarkers; D058574:Integrin-Binding Sialoprotein; D015675:Osteocalcin
keywords: Atomic force microscopy; Bone sialoprotein; Cell stiffness; MSC; Osteoblast differentiation; Osteocalcin