Effects of different pulsed ultrasound parameters and culture conditions on cell viability and sonoporation on cell membrane / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate different pulsed ultrasound (PUS) parameters and culture conditionsthat would affect cell viability and sonoporation on cell membrane of human cervical cancer cells (HeLa). MethodsHeLa cells were cultured in two different conditions ( in suspension or in monolayer). Cells were exposed to differentPUS intensity (0.4 W/cm2, 1.0 W/cm2, 1.6 W/cm2, 2.2 W/cm2), duty cycle (10%, 20%, 50%) and expo-sure time ( 1 min or 3 min). Cell viability was analyzed by flow cytometry. Using microscope and scanning electronmicroscopy (SEM) , the changes of shape and the sonoporation on cell membrane induced by PUS were observed.Results Low intensity and duty cycle did not exert a great impact on the cell viability. Cell injury was found to in-crease progressively with high intensity ( 1.6 W/cm2 , 2.2 W/cm2 ) and duty cycle ( 50% ) ( P < 0. 01 ) , and celldetachment was significantly accompanied by PUS exposure in adherent HeLa cells. Results of factorial design showedthat the culture conditions and the PUS parameters had significant interaction ( P < 0.01 ). SEM demonstrated insome detail the phenomenon of transient pores in the cell membrane under suitable PUS irradiation. The ideal sonopo-ration conditions that cell viability was above 80% and more membrane holes were noted to be at 1.0 W/cm2 expo-sure for 3 min with a duty cycle of 20% in cell suspension. Conclusion The optimized conditions of the PUS pa-rameters and the culture conditions could lower the cell injury and exert a great impact on the sonoporation. It couldproduce remarkable membrane pores on cells and enhance cell membrane permeability, which facilitate transportationof macromolecules into cells.