Preparation of Fluorescent-Magnetic Silica Nanoprobes for Recognition and Separation of Human Lung Cancer Cells

In this work, we have prepared fluorescent-magnetic silica nanoparticles (NPs) based on RuBpy-doped silica NPs and super paramagnetic Fe3O4 NPs using coating method. RuBpy-doped silica NPs (~60 nm) and Fe3O4 NPs (~10 nm) are first prepared using the reverse micro emulsion method (W/O) and the high temperature oil cracking method, respectively. Polyethyleneimine (PEI) is then conjugated to the surface of RuBpy-doped silica NPs. Coordination reaction between amines of PEI modified RuBpy-doped silica NPs and Fe3O4 is further performed in the n-hexanol to realize magnetic materials coating. After silanization and carboxylation of prepared fluorescent-magnetic silica nanoparticles (FMNPs), wheat germ agglutinin (WGA) molecules are conjugated to carboxyl-modified fluorescent-magnetic silica NPs (FMNPs-COOH, 100 nm). To demonstrate the biological application of as-prepared fluorescent-magnetic silica NPs, WGA-conjugated fluorescent-magnetic silica NPs (FMNPs-WGA) are incubated with human lung cancer A549 cells and separated by a magnetic field and then imaged using fluorescence microscopy. The results of fluorescence imaging show that fluorescent-magnetic-bifunctional nanoprobes prepared by this method could be used for highly efficient recognition and separation of cancer cells.