title: DNA-based digital tension probes reveal integrin forces during early cell adhesion.
abstract: Mechanical stimuli profoundly alter cell fate, yet the mechanisms underlying mechanotransduction remain obscure because of a lack of methods for molecular force imaging. Here to address this need, we develop a new class of molecular tension probes that function as a switch to generate a 20- to 30-fold increase in fluorescence upon experiencing a threshold piconewton force. The probes employ immobilized DNA hairpins with tunable force response thresholds, ligands and fluorescence reporters. Quantitative imaging reveals that integrin tension is highly dynamic and increases with an increasing integrin density during adhesion formation. Mixtures of fluorophore-encoded probes show integrin mechanical preference for cyclized RGD over linear RGD peptides. Multiplexed probes with variable guanine-cytosine content within their hairpins reveal integrin preference for the more stable probes at the leading tip of growing adhesions near the cell edge. DNA-based tension probes are among the most sensitive optical force reporters to date, overcoming the force and spatial resolution limitations of traction force microscopy.
authors.affiliation: Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Chenghao
authors.initials: C
authors.lastname: Ge
authors.affiliation: 1] Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, USA [2] Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA [3] Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhu
authors.affiliation: 1] Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, USA [2] Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Khalid
authors.initials: K
authors.lastname: Salaita
mesh_terms: D001696:Biomechanical Phenomena; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D004247:DNA / Q000378:metabolism*; D015342:DNA Probes / Q000378:metabolism*; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism
chemical_list: D015342:DNA Probes; D016023:Integrins; D009842:Oligopeptides; D011956:Receptors, Cell Surface; C047981:arginyl-glycyl-aspartic acid; D004247:DNA