CdSe Quantum Dots for Two-Photon Fluorescence Thermal Imaging

• Published in: Nano letters Vol. 10; no. 12; pp. 5109 - 5115
• Main Authors: Maestro, Laura Martinez, Rodríguez, Emma Martín, Rodríguez, Francisco Sanz, la Cruz, M. C. Iglesias-de, Juarranz, Angeles, Naccache, Rafik, Vetrone, Fiorenzo, Jaque, Daniel, Capobianco, John A, Solé, José García
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 08.12.2010
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Materials science; Molecular electronics, nanoelectronics; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum dots; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Thermal properties of condensed matter; Thermal properties of small particles, nanocrystals, nanotubes; Nanothermometry; quantum dots; two-photon microscopy; HeLa cancer cell; fluorescence imaging; thermal sensing; Phosphates; Quantum dots; Temperature gradients; Fluorescence; Multi-photon processes; Cadmium selenides; Nanoparticles; Thermal properties; Near infrared radiation; Fluorescent material; Temperature effects; Erbium Arsenides; Biocompatibility; Thermal imaging; Two-photon processes; Nanostructured materials; Spatial resolution; Fluorescence microscopy
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl1036098

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.