Measuring the Stiffness of Ex Vivo Mouse Aortas Using Atomic Force Microscopy.
Arterial stiffening is a significant risk factor and biomarker for cardiovascular disease and a hallmark of aging. Atomic force microscopy (AFM) is a versatile analytical tool for characterizing viscoelastic mechanical properties for a variety of materials ranging from hard (plastic, glass, metal, etc.) surfaces to cells on any substrate. It has been widely used to measure the stiffness of cells, but less frequently used to measure the stiffness of aortas. In this paper, we will describe the procedures for using AFM in contact mode to measure the ex vivo elastic modulus of unloaded mouse arteries. We describe our procedure for isolation of mouse aortas, and then provide detailed information for the AFM analysis. This includes step-by-step instructions for alignment of the laser beam, calibration of the spring constant and deflection sensitivity of the AFM probe, and acquisition of force curves. We also provide a detailed protocol for data analysis of the force curves.
Program in Translational Biomechanics, Institute of Translational Medicine and Therapeutics, University of Pennsylvania; Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania; yob@mail.med.upenn.edu.
Yong Ho
YH
Bae
Program in Translational Biomechanics, Institute of Translational Medicine and Therapeutics, University of Pennsylvania; Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania.
Shu-Lin
SL
Liu
Department of Physiology, University of Pennsylvania.
Fitzroy J
FJ
Byfield
Department of Physiology, University of Pennsylvania.
Paul A
PA
Janmey
Program in Translational Biomechanics, Institute of Translational Medicine and Therapeutics, University of Pennsylvania; Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania.
Richard K
RK
Assoian
D000818:Animals; D001011:Aorta; D001696:Biomechanical Phenomena; D002138:Calibration; D055119:Elastic Modulus; D051379:Mice; D018625:Microscopy, Atomic Force