Sensitizing of pyrene fluorescence by β-cyclodextrin-modified TiO2 nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Titanium dioxide (TiO2) nanoparticles are widely studied for their unique properties.
• Cyclodextrins are known for their ability to form inclusion complexes.
• Modifying TiO2 nanoparticles with cyclodextrins can alter their dispersibility and interactions.

Purpose of the Study:

• To synthesize water-dispersible TiO2 nanoparticles modified with beta-cyclodextrin.
• To investigate the effect of these modified nanoparticles on pyrene fluorescence.
• To elucidate the mechanism behind the observed fluorescence enhancement.

Main Methods:

• Synthesis of TiO2 nanoparticles via hydrolysis of tetraisopropyl orthotitanate in an aqueous cyclodextrin solution.
• Characterization of nanoparticle size and dispersibility.
• Fluorescence spectroscopy to measure pyrene emission in the presence of modified TiO2.

Main Results:

• Spherical TiO2 nanoparticles with an average diameter of 4.4 ± 1 nm were successfully synthesized.
• Beta-cyclodextrin-modified TiO2 nanoparticles were water-dispersible.
• Pyrene fluorescence was significantly enhanced, showing a sensitization effect three times stronger than with beta-cyclodextrin alone.
• Enhanced fluorescence is attributed to increased pyrene interaction with the cyclodextrin cavity and charge transfer with the TiO2 nanoparticle.

Conclusions:

• Beta-cyclodextrin-modified TiO2 nanoparticles offer enhanced fluorescence sensitization for pyrene.
• The observed effect is due to synergistic interactions between the cyclodextrin host, pyrene guest, and TiO2 nanoparticle.
• These findings suggest potential applications in sensing and photochemistry.