A novel magneto-fluorescent nano-bioprobe for cancer cell targeting, imaging and collection.

Silica-coated magnetic polystyrene nanospheres (MPN) containing CdTe/CdS quantum dots (QDs) and Fe₃O₄ nanoparticles were prepared, and novel anti-EGFR antibodies were conjugated onto these magneto-fluorescent nanocomposites (MPN-QDs-SiO₂) for cancer cell targeting, imaging and collection. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) images and energy-dispersive x-ray spectrometry (EDS) data showed that the MPN had been successfully coated with QDs and a silica shell, and the nanocomposites obtained with negative charged surfaces were well dispersed. The bioconjugates could be used for specifically labeling and separating cancer cells (MDA-MB-435S, SMMC-7721), but did not recognize and separate the K562 cells because the human epidermal growth factor receptor (EGFR) was not expressed on the surface. Because the anti-EGFR antibody, which we have developed, could specifically recognize certain cancer cells that highly expressed EGFR on their surface, these nanoscale bioconjugates, synchronously exhibiting fluorescence and magnetism, may be used in novel bioprobes for labeling and collecting rare cancer cells, which may be beneficial for early cancer diagnosis.