Interactions of Cardiac Proteins with Plasma-Synthesized Polypyrrole (PSPy) to Improve Adult Cardiomyocytes Culture

Plasma-Synthesized Polypyrrole (PSPy) has been reported as a biomaterial suitable for cell growth in vitro and in vivo. An experimental duplicate was carried out that showed the growth of cardiomyocytes with PSPy, following a protocol previously reported by the working group. The cardiomyocytes cultured with the biomaterial retained their native morphological characteristics, a fundamental key to improving cardiac cell therapy procedures. Such observations motivated us to investigate the molecular characteristics of the biomaterial and the type of interactions that could be occurring (mainly electrostatic, hydrogen bonds, and non-polar). Additionally, PSPy has been studied to establish the probable mechanisms of action of the biomaterial, in particular, its action on a group of cell membrane proteins, integrins, which we know participate in the adhesion of cells to the extracellular matrix, in adhesion between cells and as bidirectional signal transducer mechanisms. In this work, we carried out studies of the interactions established between cardiac integrins α2β1 and α5β1 with different PSPy models by molecular docking studies and binding free energies (ΔG_b) calculations. The models based on a previously reported PSPy molecule have three variable terminal chemical groups, with the purpose of exploring the differences in the type of interaction that will be established by modifying the position of an amino (-NH₂), a hydroxyl (-OH), and a nitrile (C≡N) in (fixed) groups, as well as the length of the terminal chains (a long/short -NH₂). A model with short chains for the -OH and -NH₂ (lateral) group was the model with the best interactions with cardiac integrins. We experimentally verified the direct interaction of cardiomyocytes with the PSPy biomaterial observed in rat primary cultures, allowing us to validate the favorable interactions predicted by the computational analysis.