Dual-emitting quantum dot/quantum rod-based nanothermometers with enhanced response and sensitivity in live cells.
Temperature is a key parameter in physiological processes, and probes able to detect small changes in local temperature are necessary for accurate and quantitative physical descriptions of cellular events. Several have recently emerged that offer excellent temperature sensitivity, spatial resolution, or cellular compatibility, but it has been challenging to realize all of these properties in a single construct. Here, we introduce a luminescent nanocrystal-based sensor that achieves this with a 2.4% change/°C ratiometric response over physiological temperatures in aqueous buffers, with a precision of at least 0.2 °C. Thermoresponsive dual emission is conferred by a Förster resonant energy transfer (FRET) process between CdSe-CdS quantum dot-quantum rods (QD-QRs) as donors and cyanine dyes as acceptors, which are conjugated to QD-QRs using an amphiphilic polymer coating. The nanothermometers were delivered to live cells using a pH-responsive cationic polymer colloid, which served to both improve uptake and release nanocrystals from endosomal confinement. Within cells, they showed an unexpected enhancement in their temperature response and sensitivity, highlighting the need to calibrate these and similar probes within the cell.
The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Aaron E
AE
Albers
Emory M
EM
Chan
Patrick M
PM
McBride
Caroline M
CM
Ajo-Franklin
Bruce E
BE
Cohen
Brett A
BA
Helms
D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry; D002470:Cell Survival; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D006367:HeLa Cells; D006801:Humans; D049408:Luminescent Agents / Q000737:chemistry*; D051379:Mice; D041681:NIH 3T3 Cells; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D012680:Sensitivity and Specificity; D013440:Sulfides / Q000737:chemistry; D013821:Thermometers
D019187:Cadmium Compounds; D049408:Luminescent Agents; D018036:Selenium Compounds; D013440:Sulfides; C034939:cadmium sulfide; C058667:cadmium selenide