Solutions and suspensions comprising polymerized hemoglobin derived from human blood are disclosed. The solutions and suspensions may comprise cell culture medium, an enzyme (such as a protease), and/or a buffer. Processes of preparing the solutions and suspensions are also disclosed. The solutions and suspensions may be employed in methods of isolating mammalian cells, such as pancreatic islets, methods of preserving mammalian tissue and organs, methods of aiding the recovery of mammalian cells following their isolation, methods of maintaining mammalian cells, methods of propagating mammalian cells, and methods of treating a mammal with diabetes.