CdSe quantum dots for two-photon fluorescence thermal imaging.
The technological development of quantum dots has ushered in a new era in fluorescence bioimaging, which was propelled with the advent of novel multiphoton fluorescence microscopes. Here, the potential use of CdSe quantum dots has been evaluated as fluorescent nanothermometers for two-photon fluorescence microscopy. In addition to the enhancement in spatial resolution inherent to any multiphoton excitation processes, two-photon (near-infrared) excitation leads to a temperature sensitivity of the emission intensity much higher than that achieved under one-photon (visible) excitation. The peak emission wavelength is also temperature sensitive, providing an additional approach for thermal imaging, which is particularly interesting for systems where nanoparticles are not homogeneously dispersed. On the basis of these superior thermal sensitivity properties of the two-photon excited fluorescence, we have demonstrated the ability of CdSe quantum dots to image a temperature gradient artificially created in a biocompatible fluid (phosphate-buffered saline) and also their ability to measure an intracellular temperature increase externally induced in a single living cell.
Fluorescence Imaging Group, Departamento de Física de Materiales, C-IV, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, Madrid 28049, Spain.
Laura Martinez
LM
Maestro
Emma Martín
EM
Rodríguez
Francisco Sanz
FS
Rodríguez
M C Iglesias-de
MC
la Cruz
Angeles
A
Juarranz
Rafik
R
Naccache
Fiorenzo
F
Vetrone
Daniel
D
Jaque
John A
JA
Capobianco
José García
JG
Solé