FRET-like fluorophore-nanoparticle complex for highly specific cancer localization.

Fluorophore mediated bio-signal retrieval has been extensively used in molecular imaging. However, only a limited number of fluorophores can be used for humans and their quantum yield is usually low. Another important issue is emitting fluorescence at the disease site, with a minimal non-specific emission at any other sites. Artificial quenching and enhancing of fluorescence was found to be possible by manipulating the distance between a fluorophore and a certain type of nanometal particle. Utilizing this unique property, we have designed a novel, FRET-like, fluorophore-nanoparticle complex. The complex emits fluorescence conditionally only at a disease site at an enhanced level. As a model system, our complex is designed to target breast cancer. As an initial step for developing this cancer locator, fluorescence alteration was studied when a spacer at various lengths is placed between a nanogold particle and a safe fluorophore.