In vivo tracking of nanoerythrosomes with gallium-68 labeling strategies

Abstract Background Nanoerythrosomes (NanoEs) are extracellular vesicle mimetics that are suitable for large-scale manufacturing utilizing donated human blood. NanoEs can be used as drug carriers for both disease treatment and diagnostics. To understand the whole-body in vivo behavior of NanoEs, we used positron emission tomography (PET) imaging to study their biodistribution. In this study, we used the [ 68 Ga]Ga- tris (8-hydroxyquinoline) complex to radiolabel NanoEs and track their biodistribution in vivo in healthy Sprague-Dawley rats. The biodistribution was compared with that of the rat control groups administered with [ 68 Ga]GaCl 3 , [ 68 Ga]Ga- tris (8-hydroxyquinoline), and [ 68 Ga]GaCl 3 -labeled NanoEs. Results [ 68 Ga]Ga- tris (8-hydroxyquinoline)-NanoE was synthesized in a two-step process, with a synthesis time of 77 ± 9 min ( n = 4) and a decay-corrected radiochemical yield of 35 ± 20% ( n = 4). The product was purified using size exclusion chromatography and analyzed using thin layer chromatography. The radiotracer was administered to the rats, followed by 60-min PET imaging, after which the tissues were collected for radioactivity quantification. [ 68 Ga]Ga- tris (8-hydroxyquinoline)-NanoE had significantly higher uptake in the liver, pancreas, and blood cells than the control groups. Conclusions It is feasible to radiolabel NanoEs as a novel type of biocompatible nanomaterial with [ 68 Ga]Ga- tris (8-hydroxyquinoline), and significant differences in PET imaging and biodistribution were observed in several tissues compared with the control groups. This is a step forward in the development of NanoE-based delivery platforms for PET imaging and therapeutic purposes.