Dynamic intracellular tracking nanoparticles via pH-evoked "off-on" fluorescence

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Cell Biology

Background:

• Dynamic tracking of nanoparticles within cells is crucial for understanding biological processes.
• Fluorescence quenching presents a significant obstacle to effective nanoparticle tracking in cellular environments.

Purpose of the Study:

• To develop a novel fluorescent nanoparticle system for overcoming fluorescence quenching during intracellular tracking.
• To create an "off-on" fluorescent probe for enhanced visualization of nanoparticles in cellular compartments.

Main Methods:

• Synthesized pH-switchable spiropyran (SP) probes.
• Incorporated SP into poly(ethylene glycol) (PEG) nanoparticles using atom transfer radical polymerization (ATRP).
• Investigated the fluorescence properties of SP-PEG nanoparticles in simulated cellular environments.

Main Results:

• Constructed "off-on" fluorescent nanoparticles with spiropyran (SP) integrated into poly(ethylene glycol) (PEG).
• Observed strong red fluorescence emission from nanoparticles upon isomerization of SP to merocyanine.
• Demonstrated efficient tracking of nanoparticles within cellular endosomes and lysosomes due to pH-triggered fluorescence.

Conclusions:

• The developed SP-PEG nanoparticles effectively overcome fluorescence quenching challenges.
• The pH-switchable "off-on" fluorescence enables efficient dynamic tracking of nanoparticles in cellular compartments.
• This approach offers a promising tool for advanced intracellular imaging and biological studies.