Both cellular biophysics and regenerative medicine rely on the merging of electronics with biological and synthetic tissues. Such integration has been developed on a two-dimensional (2D) scale and used to probe electrical activity at the surface of biological tissues. However, it has not yet been possible to provide spatiotemporal monitoring of cells throughout synthetic, biocompatible 3D scaffolds. Macroporous, freestanding nanoES can be used alone or in addition to other biocompatible scaffolds to mimic the structure of natural tissue. They are equipped with sensory capabilities that allow for the real-time monitoring of local intra- and extracellular electrical activity and pH throughout 3D cultures of neural and cardiac tissues.