An engineered cardiac patch based on biodegradable thermoplastic elastomer fabricated by 3D printing and in situ polymerization

Fabricate on conductive engineered cardiac patches (ECPs) that closely resemble the mechanical properties of natural myocardium remains challenging. In this contribution, block copolymers of Poly(gamma-methyl-E-caprolactone)-b-poly (E-caprolactone)-PEG-poly (E-caprolactone) -b-poly(gamma-methyl-E-caprolactone) (PMECLs) via sequentially ring-opening polymerization (ROP) of E-caprolactone (CL) followed by gamma-methyl-E-caprolactone (MCL) were achieved. The resulting PMECLs exhibited typical elastic characteristics of thermoplastic elastomers (TPEs) and demonstrated excellent adaptability to 3D printing. To enhance the conductivity of PMECL scaffolds, conductive polypyrrole (PPy) was in situ polymerized on the surface. As a result, electrically conductive ECPs that displayed comparable conductivity and mechanical properties to natural myocardium was successfully obtained. In vitro cellular experiments were conducted to evaluate the cytocompatibility of the ECPs, and it was found that they exhibited excellent cytocompatibility and supported cell proliferation for a duration of 7 days. Furthermore, the conductive ECPs demonstrated a significant enhancement in the expression of cardiac marker proteins (alpha-actinin, CX-43) in H9C2 cells, when compared to non-conductive ECPs. This finding suggests that the conductive ECPs played a crucial role in promoting cellular maturation and functionalization. Consequently, this conductive elastic ECPs holds great potential for application in the treatment of MI-damaged tissue.