Synthesis of novel nano-radiotracer for in-vivo molecular SPECT imaging: Nanosize chitosan and its conjugation with glutamine

This study presents the synthesis and characterization of chitosan-glutamine-based biocompatible nanoparticles (nano-conjugate) as a platform for developing an efficient nano-radiopharmaceutical agent for liver imaging. The nanoparticles were labeled with technetium-99 m, resulting in the formation of 99mTc-chitosan-glutamine. Various characterization techniques, including furrier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR) were performed for confirmation of synthesized nano-conjugate. Scanning electron microscopy (SEM), dynamic light scattering (DLS), and static light scattering (SLS) spectroscopies were employed to investigate the particle properties such as size, zeta potential, and molecular weight. MTT assay was conducted to study the toxicity of chitosan-glutamine showing that nano-conjugate had a toxicity on cancer cell in-vitro. In-vivo studies were conducted by administering 99mTc-chitosan-glutamine to mice, followed by whole body SPECT imaging. The imaging process was performed at three different time points post-injection: 15, 60, and 120 min. The SPECT results revealed a significantly accumulation in the liver. Also, biodistribution study showed that accumulation in liver (% ID/g = 23.15%) was significantly higher than other organs. Our in-vitro and in-vivo findings suggest that 99mTc-chitosan-glutamine could serve as a theranostic agent for cancer imaging using SPECT technology.