AFM Observation Of Eight Kinds Of Solutions And Human Erythrocytes Disposed By These Solutions

OBJECTIVES To find the best solutions that can be used to the preparation of human erythrocytes observed with Atomic Force Microscope(AFM), to observe fine structures in surface of erythrocytes ,and to find characteristic changes of human erythrocytes under different osmotic pressures with AFM.MATERIALS AND METHODS Eight kinds of solutions, 1% formaldehyde solution, PBS buffer(ph=7.2),citrate buffer(ph=6.0), 0.9%Nacl solution, 5%dextrose solution, TAE solution, 1640 medium and 5%EDTA-K2 solution ,were scanned by AFM . The operation mode of AFM was Contact mode. Ten areas of each kind of solutions were scanned with scan size 50 m and scan rate 1Hz.Human erythrocytes were diluted by these eight kinds of solutions , then observed by AFM separately. The operation mode of AFM was Tapping mode. Five areas of each sample were scanned. Each area was observed with scan sizes of 30 m, a erythrocyte and 1 m as well as 0.5 m (0.5 m area was the magnification of 1 m area) in both periphery and middle of membranes of erythrocytes. Scan rate was 0.5Hz~1.5Hz.Human erythrocytes diluted by 0.6%Nacl solution and 1.5% Nacl solution were also scanned by AFM. The operation mode of AFM was Tapping mode. Five areas were scanned in each kind of samples. Each area was observed with scan sizes of 30 m, a erythrocyte and 1 um as well as 0.5 m (0.5 m area was the magnification of 1 m area) in both periphery and middle of membranes of erythrocytes. Scan rate was 0.5Hz-1.5Hz. RESULTS A few of irregular granules were found in 1% formaldehyde solution, citrate buffer, 5%dextrose solution, TAE solution and 5%EDTA-K2solution. A lot of granules were found in PBS buffer with four kinds of shapes. A lot of granules were also found in 0.9%Nacl solution with four kinds of shapes. Many snowlike granules were observed in 1640 medium.Human erythrocytes disposed by 1 % formaldehyde solution, citrate buffer, 5%dextrose solution and TAB solution had few granules in background. Diameters and shapes of these erythrocytes were normal while fine structures of the membranes were featured with the shape of pores and protrusions.Compared with human erythrocytes disposed by 5%dextrose solution, erythrocytes disposed by 0.6%Nacl solution swelled, the diameters magnified, protrusions broadened and pores were cracklike. These cells disposes by 1.5%Nacl solution shrank, the diameters decreased, protrusions narrowed and pores were cracklike.CONCLUSIONS 1 % formaldehyde solution, citrate buffer, 5%dextrose solution and TAB solution are applicable to further research of erythrocytes by AFM. Pores and protrusions exist in the surface of erythrocytes. The diameters, the shapes and fine structures of membranes of human erythrocytes disposed by 0.6%Nacl solution and 1.5%Nacl solution changed under different osmotic pressure.