Fluorescence Microscopy Tracking of Cell Endocytosis Using Nanoparticle mediated Enhancement of Fluorescence

M. JULIA ROBERTI; L. ESTRADA; M. MIRENDA; A. WOLOSIUK; V. LEVI; O. MARTINEZ; P.F. ARAMENDIA

Humacao, Puerto Rico

Congreso; Panamerican Advanced Studies Institute (NSF) - PASI Nano Bio 2010; 2010

National Science Foundation of USA

Metallic nanoparticles (NPs) can enhance the emission of fluorophores through interaction of the NP plasmon with the molecule absorption and emission moment. This effect depends, among other factors, on the NP-fluorophore distance (d) and the intrinsic fluorescence quantum yield of the molecule. Our previous theorethical calculations show that such an increase produces both a gain in the brightness and photostability of the fluorescent marker, higher as the molecule fluorescence quantum yield decreases.We have recently started a detailed experimental study of this phenomenom using Au NPs (diameter ~80 nm). Different NP functionalization approaches are employed, from fluorescent-derivatized polyelectrolyte coatings to thiolated double-stranded DNA bound to the Au surface, using fluorophores such as eosin isothiocyanante (EITC) and Cy3. Our preliminary results, using AuNP-EITC nanoparticles deposited on glass and observed in a confocal microscope, show a gain in brightness dependent on d.