The process of purposely injecting external gene in to a biological cell to induce genetic changes is commonly stated as transfection. In this work, we demonstrate a new single-cell transfection technique for a cancer cell line using femtosecond laser and optical tweezers. For this purpose, plasma membrane of the cell is optoporated by 800 nm femtosecond laser followed by insertion of plasmid-coated microparticle in to the cell cytoplasm using 1064 nm trapping laser. Position monitoring of trapped particle and detection of plasma membrane is done using another 685 nm detection laser. Laser exposure parameters such as exposure energy and time are optimized to keep the cell healthy during and after the experiment. Finally, the genetic changes in the cell are confirmed 48 hours post-experiment by observing the targeted cell under a fluorescence microscope. This integration of three lasers provides high control to focus puncturing laser exactly on the cell membrane with minimal damages and successful genetic changes in to the biological cell.