99mTc-Anionic Linear Globular Dendrimer-G2-Phenylalanine Conjugate: Novel Brain Tumor SPECT Imaging

The purpose of this study was the investigation of the targeting potential of 99mTc-Labeled dendrimer-phenylalanine conjugate for brain tumor SPECT imaging. L-Type amino acid transporters (LAT1) are highly expressed in the blood-brain barrier as well as in brain cancer cells; thus, targeting LAT1 using phenylalanine could improve the sensitivity and specificity of radiosynthesis nanocarrier. In this study, the dendrimer G2–phenylalanine conjugate was synthesized and characterized by Fourier transform infrared spectroscopy, atomic force microscopy, particle size, and zeta potential. MTT assay was done for cell viability measurement in different concentrations of nanoparticles (0.125, 0.25, 0.5 mg/ml) on C6 glioma cell lines; the uptake study was evaluated using fluorescence-activated cell sorter (FACS) instrument; finally, SPECT scintigraphy in glioma tumor-bearing Wistar rats was done. The dendrimer-phenylalanine conjugate particle size was found in the range of 74.14±2.2 to 109±3.1 nm, with a slightly negative surface charge. Also, phenylalanine present on the dendrimer's surface–phenylalanine conjugate enhanced the dendrimer's cellular uptake–phenylalanine conjugate on the C6 glioma cell line. Results of SPECT imaging and fluorescence studies revealed that dendrimer–phenylalanine conjugate accumulated into the brain tumor cells, and it can be suggested as a promising brain-targeting probe with no toxicity in brain tumor imaging.