Compact hybrid (gold nanodendrite-quantum dots) assembly: plasmon enhanced fluorescence-based platform for small...

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Biophysics

Background:

• Label-free sensing is crucial for detecting small molecules in complex matrices.
• Plasmon enhanced fluorescence (PEF) offers high sensitivity but requires optimized systems.
• Gold nanodendrites (AuNDs) and quantum dots (QDs) are promising nanomaterials for optical sensing.

Purpose of the Study:

• To develop a novel PEF system for label-free sensing of small molecules.
• To investigate the assembly of amine-terminated AuNDs and carboxyl-terminated QDs.
• To evaluate the system's performance for trinitrotoluene (TNT) detection.

Main Methods:

• Direct assembly of AuNDs and QDs via amine-carboxyl attraction.
• Utilizing AuNDs with specific morphology for enhanced plasmonic effects.
• Finite-difference time domain (FDTD) calculations to understand PEF enhancement.
• Developing a sensing mechanism based on analyte-induced disruption of AuND-QD assemblies.

Main Results:

• A compact hybrid (AuND-QDs) assembly was formed, increasing PEF by 4 times.
• AuND morphology and compact assembly structure significantly enhance PEF.
• The system demonstrated sensitive TNT detection with a linear range of 0-8.8 nM and a 0.05 nM detection limit.
• Successful application of the method for TNT sensing in real environmental samples.

Conclusions:

• The developed AuND-QD hybrid system provides a highly sensitive and effective platform for label-free small molecule sensing.
• The unique properties of AuNDs and the compact assembly are key to the observed solution-PEF effect.
• This method shows significant practical potential for environmental monitoring, particularly for explosives like TNT.