en اپتیک پزشکی، میکروسکوپ نوری و بیوفوتونیک Medical Optics, Optical Microscope, Biophotonics پژوهشي Research <span style="font-size:11pt"><span new="" roman="" style="font-family:" times=""><span style="font-weight:bold">The modification of cell surface structures has become a focal point in cell biology, with methods like drugs, chemicals, and non-destructive techniques such as laser light exposure being utilized. In particular, exposure to femtosecond laser pulses has been found to increase cell permeability to formulations without causing thermal damage. This study aimed to observe and document the changes in the structure of <i>Staphylococcus aureus</i> bacteria when they were optically trapped and subjected to femtosecond laser pulses, along with the application of a medicinal substance, over 20 minutes. The research successfully determined the optimal power and exposure time of the laser light on the bacterial surface and demonstrated the ability of femtosecond laser pulses to enhance the efficacy of the medicinal substance.</span></span></span><br> &nbsp; Bacteria, cell membrane, femtosecond laser pulses, optical tweezers. 11 18 http://ijop.ir/browse.php?a_code=A-10-580-3&slc_lang=en&sid=1 Nastaran Kahrarian nastarankahrarian@gmail.com 10031947532846005421 10031947532846005421 No Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran Atoosa Sadat Arabanian a_arabanian@sbu.ac.ir 10031947532846005422 10031947532846005422 Yes Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran zinab Moradi Alvand Zmoradialvand94@gmail.com 10031947532846005423 10031947532846005423 No Research Institute of Medicinal Plants and Raw Materials, Shahid Beheshti University, Tehran, Iran Hasan Rafati h_rafati@sbu.ac.ir 10031947532846005424 10031947532846005424 No Research Institute of Medicinal Plants and Raw Materials, Shahid Beheshti University, Tehran, Iran Reza Massudi r-massudi@sbu.ac.ir 10031947532846005425 10031947532846005425 No Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran