Gold Nanocomposite Bioink for Printing 3D Cardiac Constructs

TLDR

Bioprinting enables fabrication of biomimetic 3D cardiac tissues, but conventional polymeric bioinks are poorly conductive, hindering efficient electrical coupling between cardiac cells. This study develops a gold nanorod‑incorporated gelatin methacryloyl bioink to overcome the conductivity limitation of existing bioinks. By tuning gold nanorod concentration, the nanocomposite bioink achieves a low viscosity similar to pristine inks while creating a microenvironment that supports high‑density cell spreading and organization. The optimized bioink allows rapid, high‑resolution deposition with reduced shear stress, enhances cell adhesion and organization, bridges polymer pore walls to improve cell‑to‑cell coupling, and promotes synchronized contraction, indicating strong potential for cardiac tissue engineering.

Abstract

Bioprinting is the most convenient microfabrication method to create biomimetic three‐dimensional (3D) cardiac tissue constructs, that can be used to regenerate damaged tissue and provide platforms for drug screening. However, existing bioinks, which are usually composed of polymeric biomaterials, are poorly conductive and delay efficient electrical coupling between adjacent cardiac cells. To solve this problem, a gold nanorod (GNR)‐incorporated gelatin methacryloyl (GelMA)‐based bioink is developed for printing 3D functional cardiac tissue constructs. The GNR concentration is adjusted to create a proper microenvironment for the spreading and organization of cardiac cells. At optimized concentrations of GNR, the nanocomposite bioink has a low viscosity, similar to pristine inks, which allows for the easy integration of cells at high densities. As a result, rapid deposition of cell‐laden fibers at a high resolution is possible, while reducing shear stress on the encapsulated cells. In the printed GNR constructs, cardiac cells show improved cell adhesion and organization when compared to the constructs without GNRs. Furthermore, the incorporated GNRs bridge the electrically resistant pore walls of polymers, improve the cell‐to‐cell coupling, and promote synchronized contraction of the bioprinted constructs. Given its advantageous properties, this gold nanocomposite bioink may find wide application in cardiac tissue engineering.