Additive manufacturing and advanced functionalities of cardiac patches: A review

Cardiac patches made up of polymer scaffolds and heart muscle cells have received great attention as a promising construct to repair damaged heart tissue and improve its function. There are various techniques, including solvent casting, electrospinning, and rotary-jet spinning, which are widely used for the fabrication of cardiac patches from natural, synthetic, or natural/synthetic polymers. However, limited control over the structure of patches and poor reproducibility are some of the drawbacks associated with these fabrication methods. Currently, the development of additive manufacturing 3D bioprinting technology has opened a new avenue for tissue engineering applications. 3D bioprinting techniques allow the fabrication of cardiac patches with a flexible design based on the individual patient's needs to be placed in precise geometries as found in native counterparts. Recent research has focused on the improvement and implementing various functionalities of cardiac patches. Electroconductive, drug delivery, 4D, and shape memory cardiac patches are the most recent advances in cardiac patch manufacturing. With all these developments, adhesion of the cardiac patches to heart tissue with a slippery wet surface and under dynamic forces has been challenging. The materials and strategies developed for ideal adhesion to the heart tissue are also reviewed in this paper.