Preparation of Gd-Au Dendrimer-Entrapped Gold Nanoparticles-Folic Acid Nanoparticles and Its Application in Computed Tomography/Magnetic Resonance Imaging Dual-Modality Diagnosis of Abdominal Tumors

ABSTRACTThe development of nanomaterials, especially the development of multi-modality imaging nanoprobe technology has become a reality for tumor imaging diagnosis. In this study, the gadolinium ion chelating agent (2,2′,2′′-(10-(2-(2, 5-dioxopyrrolidin-1-oxyl)-2 oxoethyl)-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7-tri)triacetic acid) (DOTA-NHS) and polyethylene glycol (PEG)-modified targeting ligand PEG-folic acid (FA) were grafted onto the PEG-modified fifth-generation polyamide-amine dendrimer (P5-NH2), which were undertaken as standards to wrap gold nanoparticles. Then, remaining amino group was acetylated to acquire Gd–Au DENPS-FA nanoparticles. Biocompatibility and cytotoxicity of nanoparticles were analyzed while characterizing them. The cases with unidentified tumors (mass diameter >4.5 cm) of abdominal or pelvic origin were selected and used for clinical study of computed tomography (CT)/magnetic resonance imaging (MRI) dual-modality abdominal tumors. In the test, average particle size of Gd-Au DENPs-FA nanoparticles was 4.2 nm, and they had good water solubility and stability in aqueous solution. When concentration of Au+ nanoparticles increased, the cell morphology remained normal, only a small number of round cells appeared, and the cell activity remained above 80%. GD-Au DENPs-FA nanoparticles had a good targeting specificity for KB cells with high folate receptor expression. During 6–24 hours of injection, the signal at the tumor site of the patient was enhanced markedly, namely the targeted gold nanoparticles were bound to the tumor tissue and the metabolic rate was slow. Based on this material, CT/MRI imaging could be performed in the patient’s body and further used for the early diagnosis of abdominal tumors.