Thermoresponsive Fluorescence Switches Based on Au@pNIPAM Nanoparticles

Area of Science:

• Nanotechnology
• Materials Science
• Physical Chemistry

Background:

• Plasmonic effects on fluorescence are well-studied, but dynamic, on-demand fluorescence switching in single nanostructures remains a significant challenge.
• Achieving reversible fluorescence switching and ensuring compatibility with diverse nanoparticles and fluorophores are key experimental hurdles.

Purpose of the Study:

• To design and demonstrate a dynamic system for reversible fluorescence switching in hybrid nanostructures.
• To utilize stimuli-responsive organic linkers for external control over fluorescence emission.
• To establish a general strategy for creating tunable nanointerfaces with on-demand optical responses.

Main Methods:

• Coupling metal nanoparticles (gold nanoparticles) with fluorophores (fluorescein) using thermoresponsive poly(N-isopropylacrylamide) linkers.
• Tuning the grafting density of the polymer linker to control nanoparticle-fluorophore distance.
• Characterization using dynamic light scattering, absorption spectroscopy, and fluorescence spectroscopy.

Main Results:

• Demonstrated reversible fluorescence switching in gold nanoparticle-fluorescein hybrid nanostructures.
• Showcased on-demand control of fluorescence emission by leveraging the thermoresponsive properties of poly(N-isopropylacrylamide).
• Confirmed the system's ability to modulate fluorescence via external temperature stimuli.

Conclusions:

• The developed system provides a general and versatile strategy for creating nanointerfaces with externally controlled, reversible fluorescence switching.
• The approach allows for precise control over the distance between metal nanoparticles and fluorophores, enabling tunable optical properties.
• This work paves the way for advanced applications in sensing, imaging, and optical devices requiring dynamic fluorescence modulation.