Specific Targeting, Cell Sorting, and Bioimaging with Smart Magnetic Silica Core–Shell Nanomaterials

Organic dye-incorporated smart silica-coated core–shell magnetic nanoparticles (MNP@SiO2) having dual-functionality (-PEG/NH2, see Figure) were easily fabricated, and the amine moieties on the NP surface were modified with maleimide functionality for specific covalent immobilization of biopolymers and bioactive small molecules. The sequence-independent immobilization of antibodies (Ab) is highlighted; Ab-modified MNP@SiO2 particles exhibit specific recognition for floating tumor cells or target the membrane of adherent breast cancer cells.