In tissue engineering applications, scaffolds made of conducting polymers can provide a pathway for communication between cells. But many such polymers quickly lose their conductivity under physiological conditions. Damia Mawad and Molly M. Stevens of Imperial College London and coworkers have devised a new way of improving the electronic stability of conducting polymers (Sci. Adv. 2016, DOI: 10.1126/sciadv.1601007). The researchers make patches out of phytic acid-doped polyaniline on top of a chitosan film. The dopant converts the polyaniline from an insulating to a conducting state, but loss of the dopant limits the conductivity lifetime. For that reason, the team uses a chitosan layer under the polyaniline, which helps hold the phytic acid in place and keeps the patch in a conductive state even after two weeks in physiological buffer. The researchers tested the patches in explanted rat hearts, both thin slices and whole hearts, and showed that the conductive patch enhanced conduction of the electric signal across heart scar tissue. By adding a photoactive dye and using visible light, the team was able to make the patches adhere to heart tissue in live rats for at least two weeks without sutures.