In this study, an AFM tip was used to penetrate the human colon cancer cells (SW480) in the culture medium containing pEGFP-N1-TRAIL plasmids. The trail plasmids encoded with the enhanced green fluorescent protein (EGFP) were moved into the SW480 cells through membrane holes created by the AFM probe. Following the penetration, the culture medium was changed into the RPMI1640 medium supplemented with 10% of fetal bovine serum and incubated for 24h. The expression of PEGFP-N1-TRAIL in SW480 cells was then observed by inverted fluorescence microscope. The experiment results indicate that the AFM tip can be used to penetrate the membranes of targeted cells individually.