Cardiac tissue engineering is a promising strategy to treat heart failure. Yet, several issues remain to be resolved including the prevention of arrhythmia caused by inefficient electrical coupling within the graft and between graft and host tissue. Here, a biohybrid hydrogel composed of collagen, alginate, and electroconductive poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is developed that exhibits extracellular matrix–mimetic fibrous structures and enhanced electrical coupling as well and cardiomyocyte maturation. Presence of PEDOT:PSS in the hydrogel improves electrical conductivity and prevents arrhythmia of tissue constructs containing neonatal rat cardiomyocytes. Moreover, it results in increasing beating frequencies reaching more than 200 beats min−1 endogenous frequencies. In addition, cardiomyocytes exhibit increased alignment and density in these constructs, improved sarcomere organization, and enhanced connexin 43 expression, suggesting maturation of the cardiac tissue. Importantly, the here developed electroconductive biohybrid hydrogels also improve maturation and beating properties of human‐induced pluripotent stem cell–derived cardiomyocytes. These cells exhibit 1.9 µm near adult sarcomeric length, enhanced beating frequency, increased speed of contraction, and larger contraction amplitude. Collectively, the data demonstrate the potential of this electroconductive biohybrid hydrogel to improve tissue engineering approaches to treat heart failure and possibly diseases of other electrically sensitive tissues.

Biohybrid hydrogels consisting of solubilized nanostructured pericardial matrix and electroconductive positively charged hydrazide-conjugated carbon nanotubes provide a promising material for stem cell-based cardiac tissue engineering.

Cardiac tissue engineering is a promising strategy to prevent functional deterioration or even to enhance cardiac function upon myocardial infarction. Here, electrospun fiber mats containing different combinations of electrically conductive polyaniline, collagen, and/or hyaluronic acid are assessed regarding material properties and compatibility with cardiomyocyte attachment and function. Microstructure analysis reveals that collagen fiber mats contain a wide range of fiber diameters after crosslinking (from ≈300 nm to ≈5 µm); all other fiber mats contain fibers in the range of ≈120 to ≈300 nm. Fiber mats exhibit comparable electrical conductivity to and greater mechanical properties than the native human myocardium, which is considered beneficial. Cell–matrix interaction analysis utilizing postnatal rat cardiomyocytes reveals that the fiber mats are non‐cytotoxic and permit cell attachment and contraction. Fiber mats containing collagen (9.89%), hyaluronic acid (1.1%), and polyaniline (PANi, 1.34%) exhibit the most favorable properties with longer contraction time, higher contractile amplitude, and lower beating rates. Improved contraction is accompanied by increased connexin 43 expression. Importantly, this fiber mat is a suitable material for human‐induced pluripotent stem cell–derived cardiomyocytes regarding cytotoxicity, cell attachment, and function. Collectively, these data demonstrate that fiber mats made of collagen, hyaluronic acid, and polyaniline are promising materials for cardiac tissue engineering.