MWCNT-Loaded PCL/PXS-PCL Bilayer Cardiac Patch for Myocardial Regeneration: An In Vitro and In Vivo Study

Recent progress in developing cardiac patches for regenerating the myocardium has opened a new hope after myocardial infarction (MI). Herein, we introduce a novel bilayer nanofiber cardiac patch composed of polycaprolactone (PCL), poly(xylitol sebacate) (PXS), and multi-walled carbon nanotubes (MWCNTs). First, we electrospun different monolayer scaffolds, including PCL, PCL/MWCNT, PCL/PXS, and PCL/PXS/MWCNTs, and characterized their physical, mechanical, and biological performance to determine the interaction effects of different material compositions on their scaffold properties. In vitro examinations confirmed the cooperative effect of PXS and MWCNT in blending with PCL to fabricate conductive and well-organized nanofibers with good biocompatibility. Subsequently, a bilayer nanofiber scaffold composed of PCL/PXS/MWCNT nanofibers electrospun over a PCL fibrous layer was fabricated to achieve an efficient structure capable of providing the desirable characteristics of a cardiac patch. The bilayer nature increased the mechanical performance of the PCL/PXS/MWCNT monolayer while preserving its appropriate wettability and acceptable conductivity. Excellent viability and proliferation of H9c2 cells on the bilayer scaffolds were observed in the live/dead assay. Moreover, cell-matrix interaction confirmed that bilayer nanofibers decrease myofibroblast differentiation of seeded NIH3T3 cells, which may be beneficial for cardiac repair post-MI. After transplantation of the bilayer nanofiber onto the infarcted heart of the MI rats for 4 weeks, the ischemic zone decreased, cardiac function significantly improved and very slightly activated macrophages were observed. These findings suggested a potentially durable nanofiber cardiac patch containing PXS for myocardial repair post-MI.