Multimodal biomaterial strategies for regeneration of infarcted myocardium

Myocardial tissue engineering (MTE) is an exciting front of research which is both highly competitive and extremely challenging for researchers. MTE aims to attenuate the functional set back in terms of cardiac output faced by the heart undergoing myocardial infarction (MI). MI results in substantial death of cardiomyocytes in the infarct zone followed by a strong inflammatory response and heart transplantation is the most common corrective measure for cardiac tissue engineering. Researchers are continuously striving to develop a better alternative to this highly invasive technique. Although numerous cell-based and cell-free strategies have been employed to bring about the repair of myocardium in recent times, the quest for optimal biomaterial still continues, owing to hurdles in design and fabrication of fully functional and efficiently engineered construct. In order to fabricate the constructs for myocardial repair, several biodegradable and non-biodegradable polymeric biomaterials have been analyzed over the years for their mechanical properties, biocompatibility with various cell types and functionality upon implantation. A hallmark of functional myocardium is its ability to propagate electrical impulses and respond to these impulses by synchronized contractions that generate forces for pumping blood for all metabolic activities of the body. For biomaterials to influence the myocardium microenvironment, suitable designs for cell recruitment and formation of functional conductive bundles are expected. The unique tissue structure and functioning of heart have prevented constructs from being proficient enough to be taken to clinical trials. Nonetheless, various tissue engineering strategies have evolved such as 3D implants, 2D patches and injectables, whose positive indications render optimism to investigators, that the tissue engineered regimen, would bring new treatments for patients who have suffered from agonizing MI. Focusing on biomaterials, this review provides an insight into such multi-modal research strategies, major advances and promising paradigm shifts in the field of myocardial tissue engineering.