To prepare a novel dual-modality imaging probe based on Cerasome nanomaterials, and evaluate its in vivo biodistribution and pharmacokinetic properties.

ICG encapsulated Cerasome was modified with chelating agent DOTA for ¹¹¹In-labeling. Normal mice firstly were used for in vivo studies. Animals were sacrificed at different time points after tail vein administration, blood samples were taken and the organs of interest were captured to evaluate the pharmacokinetic properties and in vivo biodistribution of ¹¹¹In-ICG-DPDCs. The subcutaneous Lewis lung carcinoma (LLC) tumor model in C57BL/6 mouse was established. The tumor-bearing mice were subjected to optical imaging in small animal IVIS and SPECT imaging in small animal nanoScanSPECT/CT system for tumor uptake of ¹¹¹In-ICG-DPDCs.

The size of the nanoparticle probe was about 90 nm, and the ¹¹¹In-labeling was successfully performed with 99.93% radiochemical purity after purification. ¹¹¹In-ICG-DPDCs showed excellent in vitro stability with 97.10% radiochemical purity at 48 h post-purification. In vivo blood clearance experiments showed that ¹¹¹In-ICG-DPDCs had a relative long blood circulation time with the fast and slow phase half-lives of 4.0 and 132.7 min. ¹¹¹In-ICG-DPDCs accumulated mainly in the liver and spleen, with long retention time. NanoScanSPECT/CT imaging showed that LLC tumors were significantly visualized at 4 h post-injection, and the other major accumulated organs were the liver and spleen, which were consistent with the results of biodistribution. Optical imaging showed significant uptake of the nanoparticle probe in the tumor, confirming the SPECT imaging results.

The Cerasome based probe designed could be used for tumor SPECT and optical dual-modality imaging, and has potential for therapeutic use.

Molecular probes; Cerasome; Indium radioisotopes; Tomography, emission-computed, single-photon; Optical imaging; Mice