Nanoengineering gold particle composite fibers for cardiac tissue engineering

Gold nanostructures can be incorporated into macroporous scaffolds to increase the matrix conductivity and enhance the electrical signal transfer between cardiac cells. Here we report a simple approach for fabricating 3-dimensional (3D) gold nanoparticle (NP)-based fibrous scaffolds, for engineering functional cardiac tissues generating a strong contraction force. A polycaprolactone-gelatin mixture was electrospun to obtain fibrous scaffolds with an average fiber diameter of 250 nm. In a facile method, gold NPs were evaporated on the surface of the fibers, creating nanocomposites with a nominal gold thickness of 2, 4, and 14 nm. Compared to pristine scaffolds, cardiac cells seeded on the nano-gold scaffolds assembled into more elongated and aligned tissues. The gold NPs on the fibers were able to maintain the ratio of cardiomyocytes to fibroblasts in the culture, to encourage the growth of cardiomyocytes with significantly higher aspect ratio, and promote massive cardiac sarcomeric actinin expression. Finally, engineering cardiac tissues within gold NP-based scaffolds exhibited significantly higher contraction amplitudes and rates, as compared to scaffolds without gold. We envision that cardiac tissues engineered within these gold NP scaffolds can be used to improve the function of the infarcted heart.