Contact Mechanics of an Unstable Viscoelastic Medium with Retardation as a Model for Mechanical Activation and Synchronization of Cardiac Spheroids

Abstract

Experimental results on the reaction of Cardiac Spheroids – spherical clusters of cardiac cells – obtained and studied recently by Nakano et al. are interpreted in the framework of a model of cardiac tissue as an unstable medium with retardation. Contact properties of this active medium are considered in an extended framework of the Method of Dimensionality Reduction. It is shown that the apparent activation of beating by mechanical loading owes to the synchronization of self-excited oscillations of considered unstable medium due to mechanical contact with a flexible loading unit. Increasing loading of a sphere leads, at first, to an increasing beating amplitude, which decreases again with further loading until the beating stops completely.

Keywords

• cardiac spheroids
• unstable medium
• synchronization
• contact mechanics