ABSTRACT
However, despite good results in myocardial tissue engineering, with the current methodologies and intense research activities, the gap between in vitro studies and clinical applications is still far from being overcome. There are signiŒcant limitations: 1) the stiffness of the tissue constructs is often mismatched with that of the myocardium. Such myocardium-incompatible biomechanical microenvironments may not allow cells to engraft and function properly in the infarcted heart (KoŒdis et al. 2004; Davis et al. 2005). The mismatched stiffness also might not effectively decrease myocardial wall stress and reconstruct a myocardial-like biomechanical microenvironment for attenuating cardiac dilation; 2) the tissue constructs do not
possess similar anisotropic and nanoŒbrous structural properties as that of the extracellular matrix (ECM) in the myocardium; and 3) cells within the tissue constructs have poor engraftment when implanted in vivo due to inadequate angiogenesis and low cell survival in an ischemic environment. Successful cardiac tissue engineering is largely dependent on the appropriate combination of scaffolds and cells (Radisic et al. 2004; Zimmermann et al. 2006). Therefore, nanobiomaterials should be able to crosstalk, on the molecular level (nanoscale), with cells in a precise and controlled manner, similar to the natural interactions existing between cells and the native ECM. At the same time, the basic requirements of a biomaterial should be kept; that is, the materials and their degradation products must be nontoxic and nonimmunogenic, and their degradation rate should match the rate of new tissue formation.
