Oxidative Stress and Plasma Membrane Repair in Single Myoblasts After Femtosecond Laser Photoporation.

Cell membranes are susceptible to biophysical damages. These biophysical damages often present themselves in challenging oxidative environments, such as in chronic inflammation. Here we report the damage evolution after single myoblasts were individually subjected to femtosecond (fs) laser photoporation on their plasma membranes under normal and oxidative conditions. A well-characterized tunable fs laser was coupled with a laser scanning confocal microscope. The post-damage wound evolution was documented by real-time imaging. The fs laser could generate a highly focused hole at a targeted site of the myoblast plasma membrane. The initial hole size depended on the laser dosage in terms of power and exposure duration. With the same laser power and irradiation duration, photoporation invoked bigger holes in the oxidative groups than in the control. Myoblasts showed difficulty in repairing holes with initial size beyond certain threshold. Within the threshold, holes could apparently be resealed within 100 s under the normal condition; while in oxidative condition, the resealing process could take 100-300 s. The hole-resealing capacity of myoblasts was compromised under oxidative stress particularly when the oxidative exposure was chronic. It is interesting to note that brief exposure to oxidative stress apparently could promote resealing in myoblasts after photoporation.