Preparation of 131I-loaded albumin nanopreparations and uptake in radioiodine-refractory thyroid cancer cells

Background: Radioiodine-refractory thyroid cancer is currently a difficult clinical issue and pain point. This may be related to a combination of factors such as cytokines, signaling pathways and the cell microenvironment causing damage to the cell's iodine uptake channels, mainly manifested as the decreased expression of Na/I symporter（NIS） and the loss of the best treatment strategy. This study innovatively combined targeted radionuclide therapy (TRT) with nano delivery system to build a nano targeted radionuclide therapy (NTRT) platform to solve the problem of NIS failure. Results: The nanopreparations were characterized according to their particle size, potential, morphology, encapsulation rate, radiochemical purity and stability, and the uptake of ¹³¹ I-cyclodextrin-albumin nanoparticles by SLC5A5 knockout B-CPAP cells was analyzed. the average hydrodynamic diameter, PDI and zeta potential of the prepared ¹³¹ I-cyclodextrin-albumin nanoparticles were 132.80±1.60nm, 0.21±0.02 and -29.20±0.30mV. The results of transmission electron microscopy showed that the ¹³¹ I-cyclodextrin-albumin nanoparticles were round or elliptical, without an obvious adhesion phenomenon. The distribution was relatively uniform, and the particle size was about 35-55nm. The encapsulation rate of the nanopreparation was 68.70±2.79%, and the radiochemical purity was 91.70±1.67%. SLC5A5 knockout B-CPAP cells can ingest ¹³¹ I-cyclodextrin-albumin nanopreparations, and the uptake rate is about 80.60±1.81%. It is concluded that we successfully prepared a ¹³¹ I-cyclodextrin-albumin nanoparticle preparation that can be taken up by RAIR-DTC cells with a high uptake rate. Conclusions: We have successfully developed a preliminary NTRT platform, which will be a promising alternative therapy for RAIR-DTC patients who have lost radioiodine therapy due to NIS failure.