A gold nanoparticle–knitted scaffold hybrid for tissue engineering

Three-dimensional (3D) pile loop knit fabrics made up of polyethylene terephthalate (PET) yarns are encouraging scaffolds for engineering cardiac patches aiming at preserving the native heart following acute myocardial infarction (AMI) in survivors. However, the poor conductivity of PET limits the cell housing ability of the scaffold. In this study, the depositing of gold nanoparticles (AuNPs), with a thickness of 45 nm, on the back surface of the knitted scaffold was shown to change the dielectric properties of the scaffold, and increased its conductivity by approximately twofold at 1 MHz without compromising its mechanical properties. The values of the Young’s modulus of AuNP–scaffold hybrids both in the warp (240.7 kPa) and weft directions (62.24 kPa) at 20% strain were revealed not to be far from those of the pristine scaffold (warp 177.78 kPa; weft 59.21 kPa). Transmission electron microscopy images obtained after subjecting the AuNP–scaffold hybrid to collagenase degradation assay demonstrated that the diameters of the degraded AuNPs were in the range of 3.16–92.98 nm. Furthermore, C2C12 cells on AuNP–scaffold hybrids exhibited higher cell proliferation compared with the pristine scaffold, which was attributed to conductive AuNPs providing connections between groups of cells and good alignment of connexin-43 proteins leading to a better electrical signal propagation across the scaffold. Here, it has been shown that the integration of AuNPs onto the 3D knitted scaffold can improve the biological performance of an engineered cardiac patch, contributing to its therapeutic potential for myocardial tissue engineering.