Synthesis, radiolabeling, and biodistribution of 99 m-technetium-labeled zif-8 nanoparticles for targeted imaging applications

This study investigates the synthesis and radiolabeling of zeolitic imidazolate frameworks (ZIF-8) with the radioisotope technetium-99 m (^99mTc) using a solvothermal method in methanol. The methanolic medium facilitated the formation of nanoparticles with favorable characteristics, including a smaller particle size (198 ± 9.8 nm) and a low polydispersity index (PDI = 0.219 ± 0.011). Radiolabeling efficiency (RE%) and radiochemical purity (RCP%) were optimized by employing SnCl₂ as a reducing agent, resulting in an RE% of 95.2 ± 1.9% and an RCP% of 96.1 ± 1.7% in triplicate (n = 3) at 65 °C. The nanoparticles exhibited high serum stability, retaining 99.05% of RCP% after 24 h, and demonstrated hemocompatibility, with hemolysis rates below 5% across all tested concentrations. In vitro biocompatibility assessments using NIH-3T3 cells indicated cell viability above 70% at concentrations up to 40 μg/mL. Biodistribution studies in rabbits (n = 6) revealed predominant accumulation in the bladder, with radiotracer uptake in the bladder being 6.3, 7.2, and 36.2 times higher than in the liver, kidneys, and heart (p < 0.0001), respectively, suggesting renal clearance. These results underscore the potential of ^99mTc-(ZIF-8) nanoparticles for biomedical applications, particularly in targeted imaging and drug delivery. Future research will focus on improving targeting specificity and enhancing therapeutic efficacy in disease models.