sentences:  A discontinuous Percoll gradient procedure can be used to isolate 
  infected red blood cells because red cells containing plasmodia are less dense than normal ones.Young trophozoites coincided with erythrocytes in a broad band corresponding to densities from 1.075 to 1.100 g/ml, whereas schizonts were concentrated at a density approximating 1.062 g/ml.There are studies, however, that suggest that some strains of "P.falciparum" are affected in their capacity of invasion after being exposed to this chemical.