目的 ·探讨连接胆固醇的脱氧核糖核酸 (deoxyribonucleic acid，DNA)对活细胞膜的修饰作用。方法 ·以悬浮细胞 L1210和贴壁细胞 PC-12为研究对象，将每种细胞分为实验组（胆固醇 -DNA孵育）和对照组（磷酸盐缓冲液处理）。通过共聚焦显微镜获得 2组细胞的荧光强度，并对实验组细胞进行三维重构。采用扫描电子显微镜观察实验组细胞的形态。采用荧光漂白恢复实验检测胆固醇 -DNA修饰对细胞膜流动性的影响。结果 ·悬浮细胞和贴壁细胞获得了一致的结果。与对照组相比，实验组细胞表面的荧光强度有所加强（均 P0.000）。共聚焦显微镜的三维重构显示，实验组细胞的荧光分布在整个细胞表面。扫描电子显微镜结果显示，实验组细胞的形态经胆固醇 -DNA修饰后并未改变。经荧光漂白处理后，实验组 L1210细胞的相对荧光强度下降至 0.090，且在 110 s内恢复至 0.860。结论 ·胆固醇 -DNA能够对整个活细胞膜进行修饰，且修饰后的细胞膜仍具有流动性。该方法不仅能够用于悬浮细胞，还可应用于贴壁细胞。

Objective · To investigate the modification of live cell membranes with cholesterol linked deoxyribonucleic acid (cholesterol-DNA). Methods · The suspension L1210 cells and adherent PC-12 cells were included. L1210 cells and PC-12 cells were divided into the experimental group (incubated with cholesterol-DNA) and the control group (treated with phosphate buffer saline), respectively. The fluorescence intensity of the cells in the two groups was obtained and the experimental group cells were three-dimensional reconstructedconfocal microscopy. The morphology of the cells in the experimental group was observedscanning electron microscopy (SEM). The effect of cholesterol-DNA modification on cell membrane fluidity was detectedfluorescence recovery after photobleaching. Results · The results of suspension cells and adherent cells were consistent. Compared with the control group, the fluorescence intensity of cell surface in the experimental group was increased (both P0.000). Three-dimensional reconstruction of confocal microscopy showed that the fluorescence of the cells in the experimental group was distributed across the surface of the global cell. SEM showed that the morphology of the cells in the experimental group did not change with cholesterol-DNA modification. After fluorescence photobleaching, the relative fluorescence intensity of the L1210 cells in the experimental group was decreased to 0.090, and then recovered to 0.860 within 110 s. Conclusion · Cholesterol-DNA can modify the whole live cell membranes, and the modified cell membranes still have fluidity. This method can modify not only the suspension cells, but also the adherent cells.