Cardiac tissues containing semiconductor nanomaterials and methods of preparing and using the same

Described herein are tissues containing semiconductor nanomaterials. In some embodiments, the tissues include vascular cells, cardiomyocytes, and/or cardiac fibroblasts. The tissue may be scaffold-free. In some embodiments, the tissue includes an electrically conductive network. The tissue may exhibit synchronized electrical signal propagation within the tissue. In some embodiments, the tissue exhibits increased functional assembly of cardiac cells and/or increased cardiac specific functions compared to a cardiac tissue prepared using a conventional tissue culture method. Methods of preparing and using such tissues are also described herein.