Sulfobutylether β-Cyclodextrin-Draped Gold Nanoparticles With Coumarin 30: Enhanced Fluorescence Behavior and...

Area of Science:

• Supramolecular chemistry
• Nanotechnology
• Materials science

Background:

• Coumarin dyes exhibit poor solubility and aggregation in aqueous media, limiting their applications.
• Supramolecular host-guest chemistry offers a strategy to modulate dye photophysical properties.
• Gold nanoparticles (AuNPs) are versatile platforms for drug delivery, sensing, and bioimaging.

Purpose of the Study:

• To investigate the host-guest interaction between coumarin 30 (C30) and SBE₇βCD-stabilized gold nanoparticles (AuNP-SBE₇βCD).
• To demonstrate the utility of self-assembled coumarin dye conjugates in aqueous media.
• To enhance the photophysical properties and stability of C30 for bioimaging.

Main Methods:

• Synthesis of SBE₇βCD-functionalized gold nanoparticles.
• Characterization of AuNP-SBE₇βCD stability and C30 binding.
• Spectroscopic analysis of C30 fluorescence intensity and lifetime in the AuNP-SBE₇βCD complex.
• Photostability assessment of the C30-AuNP-SBE₇βCD conjugate.
• In vivo bioimaging using Drosophila melanogaster.

Main Results:

• AuNP-SBE₇βCD demonstrated enhanced stability and reduced aggregation tendency.
• A strong binding interaction (K_b ~10⁹ M^-1) was observed between AuNP-SBE₇βCD and C30.
• Significant enhancement in C30 fluorescence intensity and lifetime was achieved due to encapsulation within the SBE₇βCD cavity.
• The AuNP-SBE₇βCD:C30 complex exhibited improved photostability.
• Prolonged bioimaging of Drosophila gut was achieved using the C30-AuNP-SBE₇βCD conjugate.

Conclusions:

• Supramolecular assembly of C30 with AuNP-SBE₇βCD effectively overcomes solubility and aggregation issues.
• This strategy significantly enhances the photophysical properties of coumarin dyes in aqueous environments.
• The developed conjugate shows promise for advanced bioimaging applications requiring high photostability and aqueous compatibility.