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Fig. 4.. A finite-element simulation optimized gel-point adhesive starch hydrogel as a mechano-active epicardial patch for treating a myocardial infarction [44]. (a) Illustration of the finite-element simulation model for the epicardial patch; (b) Effect of viscous dissipation with a Maxwell viscoelastic patch on stroke volume, pointing the optimized effect when having G"/G′ ratio ～ 1; (c) Dependence of G′, G′′ and the G"/G′ ratio of the gel-point adhesive epicardial patch (GPAP) on the frequency of oscillation, showing a gel-point viscoelastic characteristic. The GPAP not only accommodates the cyclic deformation of the myocardium but also actively interacted with it to reconstruct normal mechanical environment. Inset shows a stretched GPAP film adhering firmly on a pig epicardium; (d) GPAP significantly decreased the left ventricular relaxation time constant, indicating markedly improved biomechanical function of the left ventricle when the GPAP was applied after a myocardial infarction. (a, b, c and d reprinted with permission from [44]).