Synthesis, characterizations of dye-doped silica nanoparticles and their application in labeling cells

Spherical silica nanoparticles coated with fluorescein isothiocyanate (FITC) dyes were prepared by using an improved Stöber method. The nanoparticles were ~55 nm in diameter and were essentially mono-dispersed in aqueous solutions. The fluorescence excitation and emission spectra of the nano-composite particles showed no obvious shift compared with that of the free FITC in the aqueous solution. The photostability of FITC doped SiO(2) nanoparticles (FDSN) increased about three-fold, compared to the free FITC in the solution. The fluorescence of FDSN was tested as imaging tools using a confocal laser scanning microscope (CLSM). From the non-small cell lung cancer (NSCLC) uptake of FDSN, it was concluded that the FDSN were incorporated into these cells. The cytotoxicity assay and the NSCLC uptake of FDSN over time were also investigated in this work.