Back to Search
Start Over
Unique Energy Transfer in Fluorescein-Conjugated Au 22 Nanoclusters Leading to 160-Fold pH-Contrasting Photoluminescence.
- Source :
-
The journal of physical chemistry letters [J Phys Chem Lett] 2018 Sep 20; Vol. 9 (18), pp. 5303-5310. Date of Electronic Publication: 2018 Sep 05. - Publication Year :
- 2018
-
Abstract
- Accurate measurements of intracellular pH are of crucial importance in understanding the cellular activities and in the development of intracellular drug delivery systems. Here we report a highly sensitive pH probe based on a fluorescein-conjugated Au <subscript>22</subscript> nanocluster. Steady-state photoluminescence (PL) measurements have shown that, when conjugated to Au <subscript>22</subscript> , fluorescein exhibits more than 160-fold pH-contrasting PL in the pH range of 4.3-7.8. Transient absorption measurements show that there are two competing ultrafast processes in the fluorescein-conjugated Au <subscript>22</subscript> nanocluster: the intracore-state relaxation and the energy transfer from the nonthermalized states of Au <subscript>22</subscript> to fluorescein. The latter becomes predominant at a higher pH, leading to dramatic PL enhancement of fluorescein. In addition to the intrinsically low toxicity, fluorescein-conjugated Au <subscript>22</subscript> nanoclusters exhibit high pH sensitivity, wide dynamic range, and excellent photostability, providing a powerful tool for the study of intracellular processes.
Details
- Language :
- English
- ISSN :
- 1948-7185
- Volume :
- 9
- Issue :
- 18
- Database :
- MEDLINE
- Journal :
- The journal of physical chemistry letters
- Publication Type :
- Academic Journal
- Accession number :
- 30165739
- Full Text :
- https://doi.org/10.1021/acs.jpclett.8b02130