New Metal-Free Nanoscale Molecular Beacon
A new class of nanoscale molecular beacons, one whose members do not have metal cores, has been developed by Ulrich Wiesner, Ph.D., and his colleagues at the Cornell University. Using well-established polymer chemistry, the Cornell group is able to create spherical silica nanoparticles that incorporate fluorescent molecules, or fluorophores, within their core. The nanoparticles, which Wiesner has named CU dots, have well-defined diameters ranging from 15-30 nanometers.
The CU dots come in a variety of colors that depend on the fluorophore incorporated in the silica core. These nanoscale molecular beacons are more stable and are 20 times brighter than the corresponding fluorophore, though they are not as bright as metal-cored quantum dots and gold nanoshells. In addition, the nanoparticles can be created with reactive chemical groups on their surfaces, which will allow the CU dots to be labeled with antibodies, receptor ligands and other targeting molecules.
This work, funded in part by the National Institutes of Health, was published in Nano Letters. An abstract of the paper, titled "Bright and Stable Core-Shell Fluorescent Silica Nanoparticles," has not yet appeared on PubMed but can be viewed at the journal's website.