Protein traps nanoparticles

Proteins come in many handy shapes and sizes, which makes them major players in biological systems. Researchers from the University of Tokyo in Japan have adapted a tubular bacterial protein for technological applications by coaxing it to combine with individual luminescent semiconductor nanoparticles.

In bacteria, this chaperonin protein takes in and re-folds denatured proteins in order to return them to their original useful shapes.

Cadmium sulfite nanoparticles emit light as long as they are isolated from each other; encasing the nanoparticles in the protein keeps the tiny particles apart. The biological fuel molecule ATP releases the nanoparticles from the protein tubes, freeing the particles to clump together, which quenches the light.

The protein-nanoparticle combination could be used to detect ATP, according to the researchers. The researchers are bringing close working on using the combination to detect specific ATP concentrations. They are also working on coaxing the protein to capture and release organic molecules. This ability would make the proteins good candidates for drug carriers, according to the researchers.

The protein-nanoparticle combination could be used in practical applications in three to five years, according to the researchers. The work is scheduled to appear in the June 5, 2003 issue of Nature.