Fluorescein dye filled vesicles as models for detection of microlesions
Abstract
The primary evidence for microlesions in cell membranes caused by heavy ions is from morphological studies. This evidence, however, could not be corroborated. That said, it is possible to envision functional damage not associated with histologically discernable disruption. In order to resolve this issue experimental evidence is needed using a model that can produce reliable and unequivocal results. We developed a model system for detecting microlesions based on cell membrane mimics made of spherical vesicles 0.1 μm in diameter formed by molecules prepared from phosphatidylcholine and cholesterol. These vesicles contain the fluorescent dye calcein. We hypothesize that if microlesions form in these vesicles then upon irradiation the fluorescent dye will leak out into the surrounding medium in a measurable way. Vials containing these vesicles were irradiated at the Brookhaven National Laboratory. In one instance irradiation by 1 GeV 56Fe ions produced a significant loss of the entrapped fluorescent dye, 15 % above the background level. However, a replicate irradiation produced no leakage above the background level. Despite these initial inconclusive results we believe that the dye-filled vesicle model still has potential to clarify the microlesion hypothesis. However additional experiments are needed to validate this model in view of the contradictory results obtained in our initial experiments.
- Publication:
-
34th COSPAR Scientific Assembly
- Pub Date:
- 2002
- Bibcode:
- 2002cosp...34E2659K