Intracellular uptake of magnetite nanoparticles conjugated with RGDS-peptide

Peptides containing the Arg-Gly-Asp (RGD) motif inhibit cell adhesion and exhibit a range of other biological effects including anticoagulant and antimetastatic activities. This study examined the anchorage independent effects of an RGD-containing peptide, Arg-Gly-Asp-Ser (RGDS), on NIH 3T3 fibroblasts. Magnetite nanoparticles were prepared by the coprecipitation of ferrous iron (Fe²⁺) and ferric iron (Fe³⁺) with NH4OH and dextran (DNPs). The aminosilane agent of 3-aminopropyltriethoxysilane (A) is considered to be a candidate for modification of the surface of magnetite nanoparticles (ADNPs). The amino-functionalized magnetite nanoparticles were activated using the glutaraldehyde (G) method (GADNPs). Subsequently, RGD or RGDS peptides were immobilized on the glutaraldehyde-modified magnetite nanoparticles (RGADNPs or RSGADNPs). The RSGADNPs were evaluated using Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). The biological responses of the RSGADNPs were evaluated using NIH 3T3 fibroblast cells. Inductively coupled plasma mass spectrophotometry (ICP-MS) and Prussian blue staining showed that the RSGADNPs were internalized into the NIH 3T3 cells compared to the RGADNPs. These results suggest that RSGADNP may find ever-growing applications in biological labels and detection or contrast agents in life science and medical diagnostics.