FRET in a Polymeric Nanocarrier: IR-780 and IR-780-PDMS

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Photodynamic Therapy

Background:

• Micellar nanocarriers are promising drug delivery systems.
• Monitoring nanocarrier integrity is crucial for effective drug delivery and therapeutic outcomes.
• Förster resonance energy transfer (FRET) is a powerful tool for studying molecular proximity.

Purpose of the Study:

• To introduce a novel FRET-based method for monitoring micellar nanocarrier integrity.
• To evaluate the use of dye-loaded nanocarriers as phototoxic agents.
• To assess nanocarrier uptake, localization, and cargo release within cells.

Main Methods:

• Design of ABA-copolymer nanocarriers incorporating FRET dye pairs (IR-780-PDMS donor and IR-780 acceptor).
• Utilizing Förster resonance energy transfer (FRET) to confirm dye proximity and nanocarrier integrity.
• Employing fluorescence-lifetime imaging microscopy (FLIM) to measure FRET signals and donor fluorescence lifetime.
• Confocal laser scanning microscopy to visualize intracellular uptake and localization.
• In vitro photocytotoxicity assays using near-infrared (NIR) irradiation.

Main Results:

• FRET signals confirmed the encapsulation of the acceptor dye within the nanocarrier hydrophobic core.
• FLIM analysis revealed both intact and disintegrated nanocarriers within HeLa cells, indicating controlled cargo release.
• Confocal microscopy demonstrated intracellular uptake and granular localization of nanocarriers.
• NIR irradiation of IR-780-loaded nanocarriers induced significant photocytotoxicity in vitro.

Conclusions:

• The FRET-based method effectively monitors nanocarrier integrity during transit and within target cells.
• The study demonstrates the potential of these nanocarriers for targeted drug delivery and photodynamic therapy (PDT).
• This approach offers a valuable tool for evaluating nanocarrier-based therapeutic systems.