Preparation and characterization of magnetic nanoparticles containing Fe ₃O ₄-dextran-anti-β-human chorionic gonadotropin, a new generation choriocarcinoma-specific gene vector

Abstract

Objective:

To evaluate the feasibility of using magnetic iron oxide (Fe ₃O ₄)-dextran-anti-β-human chorionic gonadotropin (HCG) nanoparticles as a gene vector for cellular transfections.

Study design:

Fe ₃O ₄-dextran-anti-β-HCG nanoparticles were synthesized by chemical coprecipitation. The configuration, diameter, and iron content of the nanoparticles were detected by transmission electron microscopy (TEM), light scatter, and atomic absorption spectrophotometry. A3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide assay was used to evaluate the cytotoxicity of Fe ₃O ₄-dextran-anti-β-HCG nanoparticles. Enzyme-linked immunosorbent assay and indirect immunofluorescence were used to evaluate immunoreactivity. The efficiency of absorbing DNA and resisting deoxyribonuclease I (DNase I) digestion when bound to Fe ₃O ₄-dextran-anti-β-HCG nanoparticles was examined by agarose gel electrophoresis. The ability of Fe ₃O ₄-dextran-anti-β-HCG nanoparticles to absorb heparanase antisense oligodeoxynucleotides (AS-ODN) nanoparticles in different cell lines was evaluated by flow cytometry. The tissue distribution of heparanase AS-ODN magnetic nanoparticles in choriocarcinoma tumors transplanted in nude mice was detected by atomic absorption spectrophotometry.

Results:

TEM demonstrated that the shape of nanoparticles is irregular. Light scatter revealed nanoparticles with a mean diameter of 75.5 nm and an iron content of 37.5 μg/mL. No cytotoxicity was observed when the concentration of Fe ₃O ₄-dextran-anti-β-HCG nanoparticles was <37.5 μg/mL. Fe ₃O ₄-dextran nanoparticles have a satisfactory potential to combine with β-HCG antibody. Agarose gel electrophoresis analysis of binding experiments showed that after treatment with sodium periodate, Fe ₃O ₄-dextran-anti-β-HCG nanoparticles have a satisfactory potential to absorb DNA, and the protection experiment showed that nanoparticles can effectively protect DNA from DNase I digestion. Aldehyde Fe ₃O ₄-dextran-anti-β-HCG nanoparticles can transfect reporter genes, and the transfection efficiency of these nanoparticles is greater than that of liposomes ( P < 0.05). Fe ₃O ₄-dextran-anti-β-HCG nanoparticles can concentrate in choriocarcinoma cells and in transplanted choriocarcinoma tumors.

Conclusions:

The results confirm that Fe ₃O ₄-dextran-anti-β-HCG nanoparticles have potential as a secure, effective, and choriocarcinoma-specific targeting gene vector.