Third Carbonyl The Technetium Labeled Fullerenols Preparation And In Vivo Behavior Research

With their increasing applications in various aspects of national economy, nanomaterials will inevitably enter environment and then participate the ecological cycle, which must bring potential influences on human health and environmental safety. Radioisotope tracing technique has become a new approach studying ecological behavior of nanomaterials for its advantages of simplicity, high sensitivity and most important can be used in physiological condition. Taking fullerene as a model, fullerol was labeled by 99Tcm(CO)3 to study its in vivo biological behavior.Fullerene was synthesized by arc discharge method with purity identified above 99.5% by HPLC after separation and purification process. Polyhydroxyl fullerene derivative, fullerol, was synthesized and characterized by IR,1H-NMR. Elemental analysis result indicated the statistical molecular formula of fullerol could be written as C60(OH)20.[99Tcm(CO)3(H2O)3]+ was successfully synthesized starting from 99TcmO4- at 0.1 MPa CO pressure and pH 11 conditions.99Tcm(CO)3-C60(OH)20 was prepared by ligands exchange reaction of [99Tcm(CO)3(H2O)3]+with C60(OH)20. The labeling yield was above 95% under the optimum conditions (0.1 ml [99Tcm(CO)3(H2O)3]+,0.1 ml 10 mg/ml C60(OH)20 solution, pH 8, reaction time 30 minutes and 98℃boiling water bath). "One pot" method was used to prepare 99Tcm(CO)3-C60(OH)20, however, the labeling yield was only about 60%. The reason was contributed to the contradiction of pH requirements of NaBH4 and 99TcmO4-.The in vitro properties of 99Tcm(CO)3-C60(OH)20 were measured. The partition coefficient in octanol-water of the complex Po/w equaled 0.0258±0.0003 and logPo/w equaled-1.588±0.005, which indicated that the complex was hydrophilic. The complex was of well in vitro stability and anti-dilution stability. The radiochemical purity (RCP) of the complex was above 94%,93% and 90% after laid in saline, PBS and BSA for 24 h at room temperature, respectively. The RCP was above 91% after the complex was diluted 100 times in saline.The in vivo biological behavior the complex was determined by Gamma counter analysis and SPECT imaging. Results showed that the complex was stable in mice body. After intravenously injected via the tail to normal KM mice, the complex has rapid cleanup speed in blood and was unable to penetrate the blood-brain-barrier. A significant percentage of total activity was retained in 3 h, particularly in the liver, spleen, lung, thyroid, kidney and bladder, which indicated the mononuclear phagocyte system (MPS) took an important part in clearing the complex for there were full of macrophages in liver, spleen, lung and thyroid and the complex was mainly excreted through urine. The low radioactivity of all tissues and organs in 24 h indicated that the cleanup speed was rapid in whole body. The high uptake and rapid cleanup speed of the complex in important organs hinted fullerene could be used as carrier of in vivo radionuclide decorporation agents.