Topological features of erythrocytes in thalassemic patients: quantitative characterization by scanning electron and atomic force microscopy.

OBJECTIVE To examine the efficiency of scanning electron microscopy (SEM) and atomic force microscopy (AFM) in investigating structural anomalies of thalassemic erythrocytes. STUDY DESIGN Erythrocytes or red blood cells (RBCs) separated from blood samples of 35 healthy and 42 thalassemic individuals were processed for SEM and AFM imaging, respectively. SEM images were taken after erythrocytes fixed on cover slips were coated with gold. Alterations in both 2D and 3D surface features of erythrocytes were examined with AFM in tapping mode. Fractal dimension was used to estimate erythrocytes surface roughness from SEM and AFM images. RESULTS SEM and AFM images showed that healthy erythrocytes were uniform, exhibiting a typical circular and biconcave shape. Thalassemic erythrocytes were notably smaller and the central part was swollen, resulting in irregularity. In the case of SEM images it was observed that there was significant increase (p < 0.001) in roughness of thalassemic erythrocytes. Surface roughness parameters of thalassemic erythrocytes in AFM images were significantly higher (p < 0.001) as compared to healthy ones. CONCLUSION Surface characteristics of erythrocytes are important determinants for distinguishing thalassemic RBCs. Both SEM and AFM images revealed morphological deformities of thalassemic erythrocytes. AFM proved to be a powerful technique for topographical characterization of abnormal erythrocytes.