Biomimetic engineering of the cardiac tissue through processing, functionalization, and biological characterization of polyester urethanes

Three-dimensional(3D)tissuemodels offer new tools in the study of diseases. In the case of the engineering of cardiac muscle, a realistic goal would be the design of a scaffold able to replicate the tissue-specific architecture,mechanical properties, and chemical composition, so that it recapitulates the mainfunctions of the tissue. Thiswork isfocused on the design and preliminary biological validation of an innovative polyester urethane (PUR)scaffoldmimicking cardiac tissue properties. The porous scaffold wasfabricated by thermally induced phase separation(TIPS)from poly(ε-caprolactone) diol, 1,4-butanediisocyanate, and L-lysine ethyl ester.Morphological and mechanical scaffolds characterization was accomplished by confocal microscopy, and micro-tensile and compression techniques. Scaffolds were thenfunctionalized with fibronectin by plasma treatment, and the surface treatment was studied by x-ray photoelectron spectroscopy, attenuated total reflectance Fourier transform infrared spectra, and contact anglemeasurements. Primary rat neonatal cardiomyocyteswere seeded on scaffolds, and their colonization, survival, and beating activity were analyzedfor 14 days. Signal transduction pathways and apoptosis involved in cells, the structural development of the heart, and itsmetabolismwere analyzed. PUR scaffolds showed a porousaligned structure and mechanical properties consistentwith that of themyocardial tissue. Cardiomyocytes plated on the scaffolds showed a high survival rate and a stable beating activity. Serine/threonine kinase (AKT) and extracellular signal-regulated kinases(ERK) phosphorylationwas higher in cardiomyocytes cultured on the PUR scaffold compared to those on tissue culture plates. Real-time polymerase chain reaction analysis showed a significant modulation at 14 days of cardiacmuscle (MYH7, prepro-ET-1), hypertrophy-specific (CTGF), andmetabolism-related (SLC2a1, PFKL) genes in PUR scaffolds.