TARGETED DELIVERY OF EGF-QDOTS COMPLEXES INTO RAT HEPATOCYTES SUBJECTED TO HYPOTHERMIC PRESERVATION

VALERIA SIGOT; JOSÉ MANUEL PELLEGRINO; JOAQUÍN VALENTÍN RODRIGUEZ; EDGARDO ELVIO GUIBERT

Los Cocos

Simposio; First South American Spring Symposium in Signal Transduction and Molecular Medicine; 2010

Receptor mediated transport is an energy dependent mechanism requiring an available pool of ATP as well as the integrity of the cell membrane for efficient receptor activation and endocytosis. During cold storage of cells, a necessary step to preserve cells for transplant, both conditions are compromised. In order to evaluate the effect of hypothermic preservation on receptor-mediated transport, we monitored the targeted delivery of fluorescent Quantum Dots (QDs) conjugated to the Epidermal Growth Factor (EGF) ligand into cold-stored rat hepatocytes. The EGF-QDs complexes were added to cultured hepatocytes (CH) and to cold-stored hepatocytes (CSH) preserved in University of Wisconsin solution (UW) at 4°C (24 and 72 h). EGF-QDs were monitored in real time by confocal microscopy during re-warming to 37°C. After 30 min., QDs were internalized in CH and also in 24 h-CSH regardless of EGF-QDs complexes were added to the UW solution or prior to rewarming up to 37°, whereas targeted QDs remained in the cell membrane of cells preserved in UW for 72 h. Negligible binding was observed for non-targeted QDs. These preliminary observations indicate that targeted QDs may act as suitable biosensors for cold-induced membrane injury and its effect on the EGF-receptor mediated transport.