Fluorescent Nanosensor from Amphiphilic Block Copolymers Functionalized with 1,8-Naphthalimide for Acidic...

Area of Science:

• Polymer Chemistry
• Nanotechnology
• Chemical Sensing

Background:

• Amphiphilic block copolymers offer versatile platforms for nanomaterial fabrication.
• Fluorescent sensors are crucial for detecting analytes in various environments.
• Poly(N-vinyl carbazole) (PVK) exhibits interesting photophysical properties.

Purpose of the Study:

• To synthesize a novel amphiphilic block copolymer, poly(ethylene glycol)-b-poly(N-vinyl carbazole) (PEG-b-PVK), incorporating 1,8-naphthalimide.
• To investigate the self-assembly behavior of the copolymer in aqueous media.
• To evaluate the potential of the resulting nanoparticles as a fluorescent sensor for hydrogen ions in acidic environments.

Main Methods:

• Synthesis of PEG-b-PVK block copolymer via reversible addition-fragmentation chain transfer (RAFT) polymerization.
• Characterization of the copolymer using nuclear magnetic resonance (NMR) spectroscopy.
• Investigation of self-assembly into nanoparticles in aqueous solution and their photophysical properties.

Main Results:

• The synthesized PEG-b-PVK copolymer exhibited a low polydispersity index and self-assembled into uniform nanoparticles.
• Förster resonance energy transfer (FRET) from PVK to 1,8-naphthalimide resulted in enhanced fluorescence at 505 nm.
• The photoluminescence intensity showed a linear correlation with decreasing pH (3.0-6.5), indicating quantitative pH sensing capabilities.

Conclusions:

• The developed PEG-b-PVK nanoparticles function as effective fluorescent sensors for hydrogen ions in acidic media.
• The PEG shell provides protection, suggesting potential applications in biological systems.
• This study highlights the utility of functionalized block copolymers for advanced sensing applications.