The invention is directed to a device and method to prevent migration of Human Mesenchymal Stem Cells (hMSCs) from a delivery site while allowing communication between the stem cells and native cardiomyocytes. The device is characterized by scaffold pore size, fiber diameter and biomaterial selection. The invention includes a two part polyurethane scaffold that prevents migration of stem cells, allows gap junction formation through pores and is packaged for minimally invasive delivery.