Synthesis of highly stable folic acid conjugated magnetite nanoparticles for targeting cancer cells

A new approach towards the design of folic acid conjugated magnetic nanoparticles for enhancing their site specific intracellular uptake against a folate receptor overexpressing cancer cells is reported. Magnetite nanoparticles were prepared by coprecipitation from an Fe3+ and Fe2+ solution followed by surface modification with 2-carboxyethyl phosphonic acid to form carboxyl group terminated nanoparticles. Then folic acid and fluorescein isothiocyanate ( FITC) were conjugated with carboxylic acid functionalized magnetite nanoparticles using 2,2 '-( ethylenedioxy)-bis-pethylamine. These folate-conjugated nanoparticles were characterized in terms of their size by dynamic light scattering ( DLS) and transmission electron microscopy ( TEM). Surface functional groups and surface composition were analyzed by Fourier transform infrared ( FTIR) spectroscopy and x-ray photoelectron spectroscopy ( XPS), respectively. Vibration sample magnetometry ( VSM) measurements showed the superparamagnetic nature of the particles at room temperature. Folate-conjugated magnetic nanoparticles are noncytotoxic and receptor mediated internalization by HeLa and B16 melanoma F0 cancer cells was confirmed by flow cytometry and confocal microscopy.