The Distribution and Imaging of 99m Tc-nGO-PEG-FA in Human Patu8988 Tumor-Bearing Nude Mice.

BACKGROUND: To study the distribution and imaging of 99m Tc-nGO-PEG-FA in human pancreatic cancer Patu8988 tumor-bearing nude mice, and to explore its usefulness as an imaging reagent for pancreatic cancer.

MATERIALS AND METHODS: Natural graphite powder was used as raw material to prepare the nanosized graphene oxide (nGO) by using the modified Hummers method, and then was covalently modified by polyethylene glycol (PEG) on the surface of nGO. The nGO was further optimized by in vitro cell experiment, and then conjugated with the targeting molecule folic acid (FA) to form nGO-PEG-FA system. The nGO-PEG-FA was finally labeled by radioactive nuclide 99m Tc by direct labeling method to form the 99m Tc-nGO-PEG-FA molecular imaging probe. Nude mice bearing patu8988 pancreatic cancer xenografts were intravenous injection (I.V.) injected with 99m Tc-nGO-PEG-FA, and the distribution of 99m Tc-nGO-PEG-FA in nude mice at different time course was investigated by determination of tissue uptake of radioactivity (%ID/g), as well as the single photon emission computed tomography (SPECT) imaging at different time course.

RESULTS: The labeling rate of nGO-PEG-FA with 99m Tc was (90.08 ± 2.34)%, and the highest binding rate of 99m Tc-nGO-PEG-FA with Patu8988 cells was (3.15 ± 0.31)%. The radioactive uptake in tumor reached (5.11 ± 1.23)%ID/g at 6 h after I.V. injection of 99m Tc-nGO-PEG-FA in nude mice. Meanwhile, the radioactive uptake in liver, spleen, and lung was also high and reached (10.33 ± 1.22)%ID/g, (5.86 ± 0.59)%ID/g, and (3.55 ± 0.93)%ID/g, respectively, whereas less radioactivity uptake was observed in the heart (1.12 ± 0.33)%ID/g and blood (2.76 ± 0.39)%ID/g, respectively. The tumors can be clearly imaged at 4.0-6.0 h after 99m Tc-nGO-PEG-FA injection.

CONCLUSIONS: 99m Tc-nGO-PEG-FA can efficiently target pancreatic cancer, which may be developed as an imaging agent for pancreatic cancer.