title: Mean deformation metrics for quantifying 3D cell-matrix interactions without requiring information about matrix material properties.
abstract: Mechanobiology relates cellular processes to mechanical signals, such as determining the effect of variations in matrix stiffness with cell tractions. Cell traction recorded via traction force microscopy (TFM) commonly takes place on materials such as polyacrylamide- and polyethylene glycol-based gels. Such experiments remain limited in physiological relevance because cells natively migrate within complex tissue microenvironments that are spatially heterogeneous and hierarchical. Yet, TFM requires determination of the matrix constitutive law (stress-strain relationship), which is not always readily available. In addition, the currently achievable displacement resolution limits the accuracy of TFM for relatively small cells. To overcome these limitations, and increase the physiological relevance of in vitro experimental design, we present a new approach and a set of associated biomechanical signatures that are based purely on measurements of the matrix's displacements without requiring any knowledge of its constitutive laws. We show that our mean deformation metrics (MDM) approach can provide significant biophysical information without the need to explicitly determine cell tractions. In the process of demonstrating the use of our MDM approach, we succeeded in expanding the capability of our displacement measurement technique such that it can now measure the 3D deformations around relatively small cells (∼10 micrometers), such as neutrophils. Furthermore, we also report previously unseen deformation patterns generated by motile neutrophils in 3D collagen gels.
authors.affiliation: Department of Mechanical and Aerospace Engineering, California State University, Long Beach, CA 02903;
authors.forename: David A
authors.initials: DA
authors.lastname: Stout
authors.affiliation: School of Engineering, Brown University, Providence, RI 02912;
authors.forename: Eyal
authors.initials: E
authors.lastname: Bar-Kochba
authors.affiliation: School of Engineering, Brown University, Providence, RI 02912;
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Estrada
authors.affiliation: School of Engineering, Brown University, Providence, RI 02912;
authors.forename: Jennet
authors.initials: J
authors.lastname: Toyjanova
authors.affiliation: School of Engineering, Brown University, Providence, RI 02912;
authors.forename: Haneesh
authors.initials: H
authors.lastname: Kesari
authors.affiliation: Department of Surgery, Rhode Island Hospital, Providence, RI 02903; Department of Surgery, The Warren Alpert Medical School of Brown University, Providence, RI 02903;
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Reichner
authors.affiliation: School of Engineering, Brown University, Providence, RI 02912; Center for Biomedical Engineering, Brown University, Providence, RI 02912 franck@brown.edu.
authors.forename: Christian
authors.initials: C
authors.lastname: Franck
mesh_terms: D001696:Biomechanical Phenomena; D002448:Cell Adhesion; D018929:Cell Culture Techniques / Q000295:instrumentation; D002465:Cell Movement; D048430:Cell Shape / Q000502:physiology; D060833:Cellular Microenvironment; D002630:Chemotactic Factors / Q000494:pharmacology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D024042:Collagen Type I; D019245:Compressive Strength; D005782:Gels; D006801:Humans; D018613:Microscopy, Confocal; D008954:Models, Biological; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D059008:Time-Lapse Imaging
chemical_list: D002630:Chemotactic Factors; D024042:Collagen Type I; D005782:Gels; D009240:N-Formylmethionine Leucyl-Phenylalanine
keywords: confocal microscopy; large deformations; neutrophil; traction force microscopy