THE EFFECTS OF ELECTRIC-FIELDS ON PHOTOSENSITIZED ERYTHROCYTES - POSSIBLE ENHANCEMENT OF PHOTODYNAMIC ACTIVATION

In this study it has been found that exposure of photosensitized eryth rocytes to short, intense electric pulses, resulted in cell lysis. Whe n erythrocytes were photosensitized with increasing concentrations of the photosensitizer, hematoporphyrin derivative (HPD), and subjected t o electric pulses in the absence of light, cell lysis increased with i ncreasing photosensitizer concentration. In addition, it has been show n that exposure of photosensitized erythrocytes to electric field puls es of increasing field strength resulted in increased cell lysis. Ligh t activation of photosensitized erythrocytes, pre-treated with electri c pulses, also resulted in increased cell lysis. The results presented here suggest that HPD may be activated in the absence of light using electric pulses. We suggest that enhancement of activation by electric field stimulation may find application in increasing the overall effi ciency of photodynamic therapy.