We have previously described the syntheses of both magnetic and nonmagnetic polymeric microspheres, and we have reported their application in removal of neuroblastoma cells from normal cells in bone marrow, in the separation of red blood cells, and the separation of human B and T lymphocytes. In the present study, we describe a series of hydrophilic microspheres consisting of (1) poly-HEMA and (2) a copolymer sequence of HEMA-acrolein microspheres.