Development of a Novel Method to Fabricate Highly Functional Human Purkinje Networks

ABSTRACT BACKGROUND In this study, we present a method to bioengineer functional Purkinje networks using recent advances in laser-based bioprinting. METHODS A custom bioink as formulated using optimized concentrations of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GELMA), lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), and tartrazine. A standard triangle language (STL) model of Purkinje networks was developed based on the mammalian Purkinje network mapped out using India ink staining. A commercial bioprinter, the Lumen X, from CellInk, was used to bioprint Purkinje networks. The biocompatibility of the bioprinted Purkinje networks was tested using iPSCs from healthy donors. Negative molds of the Purkinje networks were designed to simulate interaction between Purkinje cells and adjacent cardiomyocytes using different degrees of overlap between the two cell types. The negative molds were also shown to be biocompatible, based on the culture of iPSCs derived from healthy donors. RESULTS We were able to successfully bioprint over 100 Purkinje networks and demonstrate biocompatibility with iPSCs for up to 7 days. Three different configurations of the negative molds were designed and fabricated and all three shown to be biocompatible with iPSCs for up to 7 days. A co-culture system was developed by placing the Purkinje networks in proximity to the negative molds for all three configurations designed. CONCLUSION Our results demonstrate the ability to bioprint Purkinje networks and molds and provide an in vitro system to study the functional interaction between Purkinje cells and adjacent cardiomyocytes.