Fabrication of a hybrid cellularized cardiac patch via 3D bioprinting of alginate-gelatin-PEOz patterns on electrospun PLCL-PEOz nanofibers

Abstract

Cellular cardiac patches for treating myocardial infarction (MI) need to exhibit both structural fidelity and functional features for their effective regeneration. To achieve a biomimetic patch, we report the development of a hybrid cellular cardiac patch by integrating electrospinning and extrusion-based three-dimensional (3D) bioprinting. A thermoresponsive bioink composed of sodium alginate-gelatin-polyethyl oxazoline (AGP) was optimized for direct printing onto an electrospun nanofiber support matrix. Electrospun-aligned B73 (a 7 : 3 blend of poly(L-lactide-co-ε-caprolactone) (PLCL) and polyethyl oxazoline (PEOz)) hydrophilic nanofibers were used as the support matrix, which offered oriented topographical cues and heterogeneous nanofiber distribution. Following the bioprinting, dual crosslinking using calcium chloride and microbial transglutaminase enhanced the Young's modulus (193 ± 63 kPa), ultimate tensile strength (285 ± 59 kPa) and long-term stability of the patch. In vitro studies of the hybrid cardiac patch (AGP-B73) produced by bioprinting primary neonatal rat ventricular cardiomyocytes (NRVCMs) encapsulated in AGP bioink onto the aligned B73 nanofiber surface demonstrated robust cell viability, contractility, anisotropy and maturation. Evaluation using a 2D hypoxia/reoxygenation (H/R) in vitro model showed that patch implantation preserved the NRVCM viability under hypoxic stress. This study serves as a proof of concept for the AGP-B73 cardiac patch as a promising candidate for MI treatment and potential drug testing applications.