02432nas a2200361   4500000000100000000000100001008004000002260001700042653001400059653002800073653003100101653001800132653001200150100001600162700001600178700002700194700002000221700001800241700001500259700002000274700002300294700001900317700001100336700001800347700002900365700001700394700001600411245012600427856006700553300001200620520142400632022001402056       23                             d  c23 July 202310aafterload10acardiac in vitro models10aforce application on cells10amagnetic gels10apreload1 aMoran Yadid1 aMario Hagel1 aMegan Beldjilali Labro1 aBaptiste Le Roi1 aCarina Flaxer1 aEli Flaxer1 aA. Ronny Barnea1 aShai Tejman-Yarden1 aEric Silberman1 aXin Li1 aRossana Rauti1 aYael Leichtmann-Bardoogo1 aHongyan Yuan1 aBen M. Maoz00aA Platform for Assessing Cellular Contractile Function Based on Magnetic Manipulation of Magnetoresponsive Hydrogel Films  uhttps://onlinelibrary.wiley.com/doi/abs/10.1002/advs.202207498  a22074983 aDespite significant advancements in in vitro cardiac modeling approaches, researchers still lack the capacity to obtain in vitro measurements of a key indicator of cardiac function: contractility, or stroke volume under specific loading conditions—defined as the pressures to which the heart is subjected prior to and during contraction. This work puts forward a platform that creates this capability, by providing a means of dynamically controlling loading conditions in vitro. This dynamic tissue loading platform consists of a thin magnetoresponsive hydrogel cantilever on which 2D engineered myocardial tissue is cultured. Exposing the cantilever to an external magnetic field—generated by positioning magnets at a controlled distance from the cantilever—causes the hydrogel film to stretch, creating tissue load. Next, cell contraction is induced through electrical stimulation, and the force of the contraction is recorded, by measuring the cantilever's deflection. Force–length-based measurements of contractility are then derived, comparable to clinical measurements. In an illustrative application, the platform is used to measure contractility both in untreated myocardial tissue and in tissue exposed to an inotropic agent. Clear differences are observed between conditions, suggesting that the proposed platform has significant potential to provide clinically relevant measurements of contractility.  a2198-3844