A far-red FRET fluorescent probe for ratiometric detection of L-cysteine based on carbon dots and N-acetyl-L-cysteine-capped gold nanoparticles
Abstract
A novel far-red fluorescence resonance energy transfer (FRET) fluorescent probe for ratiometric detection of L-cysteine (L-Cys) has been designed. The system was established a FRET assembly by positively charged carbon dots (CDs) and negatively charged N-acetyl-L-cysteine capped gold nanoparticles (NAC-AuNPs). The fluorescence of CDs at 539 nm could be effectively quenched in the presence of NAC-AuNPs owing to FRET process, while the emission of NAC-AuNPs at 630 nm was appeared. Subsequently, the interactions between L-Cys and NAC-AuNPs resulted in the decreased emission intensity of NAC-AuNPs, but the emission intensity of CDs kept almost constant due to the continuous FRET efficiency. The ratio of emission intensities at 539 and 630 nm (I539/I630) exhibited a linear correlation to the L-Cys concentration in the range of 1.0-110 μM with the detection limit of 0.16 μM. Moreover, this far-red ratiometric sensor also revealed excellent selectivity toward L-Cys over other amino acids, which showed very high potential in the practical application for diagnosing of cysteine-related disease.
- Publication:
-
Spectrochimica Acta Part A: Molecular Spectroscopy
- Pub Date:
- April 2019
- DOI:
- 10.1016/j.saa.2019.01.040
- Bibcode:
- 2019AcSpA.213...90D
- Keywords:
-
- Carbon dots;
- Gold nanoparticles;
- L-cysteine;
- Fluorescence resonance energy transfer