关键词: 近红外核交联聚合胶束纳米粒子, 肿瘤靶向, 双模态显像, 铟-111

The multi-modality probes are essential for multi-modality imaging. Dual labeled imaging probes allow the same target to be evaluated with two different modalities. Based on the structure of c-RGD peptide motif, some examples of multimodality agents have been reported in design of RGD for α_vβ₃ intergin positive tumor imaging. The aim of this study was to develop a dual-labeled nanoparticles for both single photon emission computed tomography (SPECT) and near-infrared fluorescence (NIRF) imaging of α_vβ₃. In this paper, c-RGD was conjugated to near-infrared fluorescence fluorophores (Cy7) entrapped polyethylene glycol-coated, core-crosslinked polymeric micelles (NIRF-CCPM) labeled with a radioisotope indium 111. The labeling efficiency was over 96%, the radio chemical purity was over 99% after purification. The in vitro stability tests were presented in 5% bull serum albumin (BSA) for 72 h at 25 ℃. Less than 10% ¹¹¹In dissociation was detected by Radio-Thin-Layer Chromatography. ¹¹¹In-CCPM-RGD seems to be a promising candidate for dual optical and nuclear imaging applications in tumor detection. Its structure was fully characterized. Serial SPECT imaging of human glioma U87 tumor-bearing nude mice revealed that tumor uptake of ¹¹¹In-CCPM-RGD got a substantial growth from 24 h to 72 h after post-injection of 11.1 MBq nanoparticles, corroborated by in vivo NIRF imaging. Tumor uptake as measured by in vivo NIRF imaging by region of interest (ROI) with the unit of average radiant efficiency. The ROI of tumor NIRF imaging were 4.81×10⁷ and 6.91×10⁷ [p/sec/cm²/sr]/[μW/cm²] at 24 h, 72 h respectively. The in vivo SPECT imaging was general concordance with NIRF imaging. The combination of these nuclear and NIRF imaging technologies will significantly improve the accuracy in tumor diagnosis. The persistent, excellent, and α_vβ₃-specific uptake of ¹¹¹In-CCPM-RGD in the tumor, observed by both SPECT and NIRF imaging, warrants further investigation and future clinical translation of such nanoparticles-based imaging agents.

Key words: core-crosslinked polymeric micelles, tumor target, dual-modality imaging, indium-111