Selective induction of molecular- to tissue-level anisotropy on peptide-based optoelectronic cardiac biointerfaces

The anisotropic conduction velocity in cardiac tissues, crucial for ensuring synchronized muscular contractions and overall cardiac health, is highly dependent on the orientation of individual myocytes. Similarly, for abiotic conducting materials, the ordering of charge-transporting domains dictate the conduction efficiency of the resulting material. In this study, we present a photocurrent-generating cardiac biointerface that investigates the sensitivity of cardiomyocytes to geometrically comply with biomacromolecular cues differentially assembled on a conductive nanogrooved substrate. Specifically, we develop photoconductive substrates with surface-templated 1D nanostructures of peptide-quaterthiophene (4T)-peptide units on nanoimprinted polyalkylthiophene substrates, which can further induce cardiomyocyte alignment. Using this patterned biointerface, smaller monomers were observed to achieve a high degree of assembly order on the polymeric templates and served as a more efficient driver of cardiac anisotropy than merely presenting patterned bioadhesive cues on a nanotopographic surface. These results unravel insights on how cardiomyocytes perceive the dimensionality, local molecular order, and other surface cues from their immediate environment. Overall, our work offers a cardiac patterning platform that could be photoexcited and presents the possibility of light-based cardiac stimulation of non-genetically modified cells, where conduction directionality of the biotic and abiotic components can be hierarchically controlled from the molecular- to tissue-level.