QUANTUM DOTS LIGHTING THE INTRACELLULAR WAY

VALERIA SIGOT

Mar del Plata

Taller; 2° Taller de Órganos Artificiales, Biomateriales e Ingeniería deTejidos; 2011

INTEMA

Continuous cell imaging has been dramatically improved with the introduction of Quantum Dots (QDs), colloidal nanocrystals with unique optical properties for long-term and multicolor imaging. Particularly, emission wavelengths of QDs are size-tunable, ranging from 400 to 1350 nm for nanoparticles cores between 2 to10 nm in size. QDs conjugated with ligands and antibodies can be delivered to precise cellular targets, detecting biomolecules with a sensitivity extending to single particle. Furthermore, molecular engineering of the QDs surface allows activation of signaling pathways, sensing protein-protein interactions, tracking of membrane receptors in live cells, and long-term in vivo animal imaging. An important unresolved challenge is to release monodisperse QDs into the cytoplasm, considering that most of the delivery pathways involves endocytic uptake leading to QDs trapped in endo-lysosomal compartments. Current strategies point to the embedding of QDs in pH and temperature responsive polymers, liposomes and micelles in order to significantly increase the uptake by cells and to facilitate endosomal escape. The expectation is that QD-based targeted carriers will constitute a new means for the effective delivery of therapeutic macromolecules. However, QD biocompatibility and potential toxicity remain critical issues to employ them in humans, limiting their application in “in vitro” systems or in animal models. This presentation summarizes our experience in targeted delivery of QDs into cultured and cold stored rat hepatocytes, as well as novel applications of QDs as nanocarriers and biosensors in live cell imaging.