The collected enzyme-solution is next centrifuged, the supernatant discarded, and the cardiomyocyte fraction re-suspended in ADS containing fetal calf serum. Further purification of cardiomyocytes can be attained using percoll gradients and centrifugation [34]. Cells are then plated and often cultured using methods described below. For further details on neonatal cell isolation please consult the protocol in Appendix 3, which has been modified from protocols developed by Professors Kai Wollert, Masahiko Hoshijima, and Ken Chien