Researchers have begun to focus on decellularization for organ transplants since it reduces the chance of rejection to almost none. This process was used in the first successful stem-cell based organ transplant by removing the cells and MHC antigens from the donor organ. There are different ways to remove the cells from the organ which can include physical, chemical, and enzymatic treatments.  This method is especially useful when trying to create a neo-heart because the heart needs to be created in a way where the structure remains. Since the stem cells used are currently not able to maintain a shape, researchers have started to look more into decellularization of existing organs to be able to perform successful transplant procedures without the problem of rejection. While this method may assist with the problem of rejection, donors are still needed to provide this structure to patients.