Specimens were embedded in CRYO-OCT Compound (Andwin Scientific, Tryon, NC) and frozen at ?80C. our study suggested that this porous nanofibrous PLLA scaffolds support cardiac tissue formation from CPCs. The integration of CPCs with the nanofibrous PLLA scaffolds represents a promising tissue engineering strategy for cardiac repair. Keywords: Embryonic stem cell, Cardiovascular progenitor cell, Cardiac differentiation, Extracellular matrix, Porous nanofibrous scaffold, Cardiac tissue engineering Graphical abstract 1. Introduction Myocardial infarction (MI) frequently leads to irreversible cell loss and scar formation, and ultimately to heart failure due to the inability Aurantio-obtusin of the myocardium to heal itself . In patients with severe MI, heart transplantation is the only efficacious therapy . However, there is a chronic shortage of human donor tissues, and there are rejection complications in recipients. Therefore, new technologies for heart tissue regeneration, for example, cell-based therapies, such as intracoronary and intramyocardial cell injections, have been explored to repopulate the damaged cardiac tissue with therapeutic cells . Unfortunately, these approaches were largely hampered by the poor retention and rapid death of the administered cells after engraftment. Thus, there is an urgent need to develop novel strategies to improve the retention of therapeutic cells and promote their cardiac differentiation for regeneration. One such solution is usually to integrate cardiac stem cells and biodegradable scaffolds to generate functional heart tissue [4, 5]. As mature heart tissue is mainly composed of cardiomyocytes, smooth muscle Rabbit polyclonal to AGO2 cells, endothelial cells, and pacemaker cells , it is desired for the seeded cells to be multipotent towards these lineages for cardiac repair. Embryonic cardiovascular progenitor cells (CPCs), expressing Mesp1, ISL1, or Nkx2-5, have been identified during cardiogenesis [7C9]. These cells are multipotent and can differentiate into cardiomyocytes, easy muscle cells, and endothelial cells. The CPCs derived from embryonic stem cells (ESCs) have a similar capacity to differentiate Aurantio-obtusin into the three major lineages in vitro. Aurantio-obtusin The protocol to direct ESCs towards CPCs facilitates their subsequent differentiation for cardiac tissue regeneration and ensures to a certain degree the safety to use these cells, preventing uncontrolled differentiation leading to teratoma formation . It remains a challenge to differentiate CPCs down the main desired lineages to form integrated and functional cardiac tissue. Biomaterials can assist cell survival, integration and communication with a proper microenvironment that closely mimics the native tissue architecture [11, 12], and therefore, might promote the proper differentiation and maturation of CPCs for cardiac tissue regeneration. Various types of scaffolds, including natural [13C18] and synthetic [19C22] biomaterials, have been explored to accommodate heart tissue cells. Natural biomaterials show good biocompatibility, but may lack ideal physical properties, degradation profiles, or consistency during production . In contrast, synthetic scaffolds are advantageous in their pure chemical composition, good mechanical performance, controllable degradation rate, and can be tailored with significantly lower batch-to-batch variation . However, these synthetic scaffold materials need to mimic certain advanced features of the natural extracellular matrix (ECM) to improve biological performance . Nanoscale design can tailor biomaterials to closely mimic the ECM . Porous scaffolds with nanotopographical features to imitate ECM in native Aurantio-obtusin tissues may benefit the interactions between seeded cells and scaffolds, new ECM formation, as well as the intercellular connections. The fibrous structure of tissue matrix is known to be critical to cellular functions [27C29]. Thus, our lab recently developed a phase-separation technique to fabricate nanofibrous (NF) poly(l-lactic acid) (PLLA) matrix, which enhanced aortic smooth muscle cell differentiation . Furthermore, the NF PLLA scaffolds with improved macroporous structure were found to.