Carbon Nanomaterials for Sorption of (68)Ga for Potential Using in Positron Emission Tomography

In present work, carbon nanomaterials (CNMs) are investigated as potential carriers of (68)Ga, which is widely used in positron emission tomography (PET) in nuclear medicine. Sorption behavior of (68)Ga was studied onto CNMs of various structures and chemical compositions: nanodiamonds (ND), reduced graphite oxide (rGiO) and multi-walled carbon nanotubes (MWCNT), as well as their oxidized (ND–COOH) or reduced (rGiO–H, MWCNT–H) forms. The physicochemical properties of the nanoparticles were determined by high resolution transmission electron microscopy, x-ray photoelectron spectroscopy, dynamic light scattering and potentiometric titration. The content of (68)Ga in the solutions during the study of sorption was determined by gamma-ray spectrometry. The highest degree of (68)Ga sorption was observed on ND and ND–COOH samples, and the optimal sorption conditions were determined: an aqueous solution with a pH of 5–7, m/V ratio of 50 μg/mL and a room temperature (25 °C). The (68)Ga@ND and (68)Ga@ND–COOH conjugates were found to be stable in a model blood solution—phosphate-buffered saline with a pH of 7.3, containing 40 g/L of bovine serum albumin: (68)Ga desorption from these samples in 90 minutes was no more than 20% at 25 °C and up to 30% at 37 °C. Such a quantity of desorbed (68)Ga does not harm the body and does not interfere with the PET imaging process. Thus, ND and ND–COOH are promising CNMs for using as carriers of (68)Ga for PET diagnostics.