Scientists have developed a fluorescent probe technology that can be switched on and off in the aqueous environment of cells to monitor biological processes. The technology, devised by a team at the University of Miami, uses water-soluble polymer nanoparticles as carriers for probes that can be switched on and off using ultraviolet light.
Research team head, Francisco Raymo, Ph.D., says the system is faster and more stable than current methods. The fluorescent molecules glow when exposed to UV and visible light at the same time, but revert back to a nonfluorescent state within 10 microseconds of turning of the UV. “Finding a way to switch fluorescence inside cells is one of the main challenges in the development of probes for bioimaging applications,” Dr. Raymo explains. “Our fluorescent switches can be operated in water, efficiently offering the opportunity to image biological samples with resolution at the nanometer scale … The polymers can preserve the properties of the fluorescent molecules and at the same time assist the transfer of the molecules into water.”
Importantly, the particles can be engineered to bind to specific molecules, enabling the visualization of target cellular structures and activity, in real time, and at a resolution the researchers maintain isn’t possible using current technologies. And because the system uses synthetic constructs it isn’t affected by the degrading effects UV light has on organic molecules. “The system can be switched back and forth between the fluorescent and no-fluorescent states for hundreds of cycles, without sign of degradation,” Dr. Raymo says.
The team describes its technology in Chemistry–A European Journal, in a paper titled “Fast Fluorescence Switching within Hydrophilic Supramolecular Assemblies.”