Gold Nanocomposite Bioink for Printing 3D Cardiac Constructs

Abstract

Bioprinting is the most convenient microfabrication method to create biomimetic three-dimensional (3D) cardiac tissue constructs, which 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, we developed a gold nanorod (GNR) incorporated gelatin methacryloyl (GelMA)-based bioink for printing 3D functional cardiac tissue constructs. The GNR concentration was adjusted to create a proper microenvironment for the spreading and organization of cardiac cells. At optimized concentration of GNR, the nanocomposite bioink had a low viscosity, similar to pristine inks, which allowed for the easy integration of cells at high densities. As a result, rapid deposition of cell-laden fibers at a high resolution was possible, while reducing shear stress on the encapsulated cells. In the printed GNR constructs, cardiac cells showed improved cell adhesion and organization when compared to the constructs without GNRs. Furthermore, the incorporated GNRs bridged the electrically resistant pore walls of polymers, improved the cell-to-cell coupling, and promoted synchronized contraction of the bioprinted constructs. Given its advantageous properties, this gold nanocomposite bioink may find wide application in cardiac tissue engineering.

Extrusion Bioprinting of Shear‐Thinning Gelatin Methacryloyl Bioinks

“…These overly high concentrations of GelMA bioinks resulted in limited cell activities in the bioprinted constructs due to the relatively high stiffness of the crosslinked constructs. On the other hand, we have recently designed a microfluidic printhead for direct bioprinting of GelMA constructs using alginate/GelMA as the composite bioink [20, 26] , where the alginate component was selectively removed after bioprinting to leave only GelMA. Nevertheless, this strategy could only deposit microfibrous structures carried by the outer crosslinking sheath flow containing CaCl 2 , and thus smooth integration of the bioprinted microfibers into a single tissue unit cannot be achieved.…”

Beyond the Modification Degree: Impact of Raw Material on Physicochemical Properties of Gelatin Type A and Type B Methacryloyls

“…Formulations of GM(A) with adjusted properties are also increasingly used for sophisticated fabrication techniques such as inkjet‐printing, robotic dispensing, fused deposition modeling, or two‐photon polymerization . Differences in mechanical properties of resulting GM hydrogels and tissue‐specific additives are utilized to emulate most diverse tissues such as bone, cartilage, adipose tissue, cardiac tissue, and as matrix for formation of capillary structures . GM hydrogels with different cross‐linking densities were also utilized for drug delivery applications …”

Nano‐ and Microfabrication for Engineering Native‐Like Muscle Tissues

“…And electromechanical coupling between CMs were observed. Conductive additives, including reduced graphene oxide, gold nanorod, and carbon fibers are added into hydrogels to improve their conductivity and promote the function of engineered tissues. Engineered skeletal muscle tissues may present specific responses upon external electrical stimulations .…”