An experimental study of the use of ultrasound to facilitate the loading of trehalose into platelets.

Trehalose is widely used as a freeze-drying protectant in biomaterial preservation. For this purpose, trehalose has to be loaded into the cells but this is difficult and many methods have been tried. The application of ultrasound can temporarily permeabilize cell membranes, which offers a non-chemical, non-viral, and non-invasive method of cellular drug delivery. Ultrasound is employed here to enhance the loading of trehalose into human platelets. Two frequencies were used, 25 kHz and 800 kHz. The estimated intensity of ultrasound in the sample was varied from 0 to 1.5 W/cm(2). The trehalose concentration in the platelets was 11.27+/-2.53 mmol/L when Wolkers et al.'s method was used without ultrasound. The application of 0.8 W/cm(2), 800 kHz ultrasound for 1h increased the concentration of trehalose loaded by 54%. The application of 0.8 W/cm(2), 25 kHz ultrasound for 30 min increased the trehalose concentration that was loaded by 172%. The number and mean volume of the platelets following ultrasonic radiation in these two cases remained normal as compared with fresh untreated platelets. Morphological examination of the radiated platelets showed slight changes. Although further work is needed, ultrasound has been shown to be efficient for the loading of trehalose into platelets.