原子力显微镜对中性粒细胞与K562细胞超微结构及机械性能的探测

Ultrastructure and Mechanical Property of Neutrophilic Granulocyte and Leukemia Cell K562 Detected by AFM

采用原子力显微镜在纳米尺度下对正常中性粒细胞与白血病细胞株K562细胞的表面形貌及细胞的硬度、粘附力进行定性定量分析。结果表明,相比正常中性粒细胞的平均粗糙度(Ra=5.31±1.52 nm),K562细胞的超微结构更为复杂,细胞表面平均粗糙度显著升高(Ra=26.54±8.01 nm)。此外,细胞的生物机械特性也有显著差别:中性粒细胞的硬度为9.5±1.3 kPa,AFM针尖与中性粒细胞的非特异性粘附力为135±23.4 pN;K562细胞的硬度为3.0±0.8 kPa,AFM针尖与K562细胞的非特异性粘附力为95±15.6 pN。AFM在单细胞水平上的探测表明,中性粒细胞和K562细胞的超微结构和机械特性均有明显差异。通过对细胞表面超微结构和力学特性的探测可以诊断慢性粒细胞白血病,原子力显微镜有望成为临床肿瘤诊断的工具。

An atomic force microscope （AFM） was used to detect morphological and mechanical properties of K562 cells and neutrophilic granulocyte. The result indicated that, comparing with the average roughness of normal neutrophilic granulocyte（Ra = 5.31 ± 1.52 nm）, the uhrastructure of K562 cell was more complex, and Ra value（Ra =26.54 ± 8.01 nm） was higher than that of normal neutrophilic granulocyte. The volumes of K562 cell and neutrophilic granulocyte were 377.18 ± 27.33 μm^3 and 150. 09 ± 12.23 μm^3 , respectively. The surface areas of K562 cell and neutrophilic granulocyte were 511.23 ± 28.56 μm^2, 162. 10 ± 19.20 μm^2, respectively. In addition, the nanomechanical properties of the two kinds of cells were also different. The cell stiffness of K562 cell was 3.0 ± 0. 8 kPa while that of neutrophilic granulocyte was 9.5 ± 1.3 kPa. The tip-cell-surface adhesive force of K562 was 95 ± 15.6 pN whereas that of neutrophilic granulocyte was 135 ±23.4 pN. There were significant changes in morphological and mechanical properties between K562 cell and neutrophilic granulocyte. Therefore, AFM could be a useful tool to diagnose cancer at single cell level.