Atomic force microscopy study of erythrocyte shape and membrane structure after treatment with dihydropiridinic drug

The overall shape and membrane surface of human erythrocytes (RBC) in the presence of nifedipine (a dihydropyridinic drug used in the clinical treatment of hypertension and angina pectoris) was imaged by contact-mode atomic force microscopy (AFM). Nifedipine induces in RBCs relevant morphological changes whose extent increases as a function of drug concentration and incubation time. The modifications have been interpreted as mainly due to insertion of nifedipine into the outer layer of RBC membrane. The potential effect of nifedipine as hemoglobin denaturant has been ruled out by XANES and optical spectroscopies.