Highly selective ratiometric fluorescent probe for Au3+ and its application to bioimaging

Area of Science:

• Chemical Sensing
• Fluorescent Probes
• Bioimaging

Background:

• 4-Amino-1,8-naphthalimides are versatile fluorescent probe platforms due to their intramolecular charge transfer (ICT) properties.
• Probe 1 utilizes a propargylamine moiety on the naphthalimide core for specific interactions.
• Gold(III) ion detection is crucial in various chemical and biological applications.

Purpose of the Study:

• To develop and characterize a novel fluorescent probe (1) for selective detection of gold(III) ions.
• To investigate the sensing mechanism and spectral changes upon interaction with Au(3+).
• To evaluate the probe's utility in real-time sensing and bioimaging applications in live cells.

Main Methods:

• Synthesis and characterization of the 4-propargylamino-1,8-naphthalimide probe (1).
• Spectroscopic analysis (absorption and emission) to study the interaction with Au(3+).
• Evaluation of probe performance in the presence of surfactants and application in live-cell bioimaging.

Main Results:

• Probe 1 demonstrated selective and sensitive detection of Au(3+) with a visible color change from yellow to light pink.
• A significant blue shift of approximately 56 nm was observed in the emission spectra upon Au(3+) binding.
• Surfactants enhanced the reaction rate, enabling real-time sensing; successful bioimaging of Au(3+) in live cells, particularly in lipid droplets, was achieved.

Conclusions:

• The 4-propargylamino-1,8-naphthalimide probe (1) functions as an effective chemodosimeter for Au(3+) detection.
• The probe's rapid response and enhanced performance with surfactants make it suitable for real-time applications.
• Probe 1 shows promise for intracellular Au(3+) sensing and bioimaging, highlighting its potential in biological studies.