Facile Synthesis of Polymeric Nanoprobes for Actively Targeted and High-Performance MR/CT Dual-Modal Imaging of Rheumatoid Arthritis

This study reports a facile approach for the green synthesis of a high-performance magnetic resonance/computed tomography (MR/CT) dual-modal imaging nanoprobe. The probe, designated as NPs-TCZ, is synthesized via one-step self-assembly of two amphiphilic block copolymers, namely, PEG-DTIPA-TCZ and pal-GGGGHHHHD. The NPs-TCZ exhibits a high longitudinal relaxivity (9.60 mM^-1 s^-1) and X-ray absorption (58.2 Hu mM^-1), as well as excellent water solubility and biocompatibility. The MR/CT dual-modal imaging can synergistically visualize synovial inflammation and bone erosion, which are both important clinical indicators for assessing arthritis severity, enabling sensitive diagnosis and prognostic assessments of rheumatoid arthritis (RA). The active targeting capability of tocilizumab (TCZ) enables the specific accumulation of NPs-TCZ at inflamed joints rather than healthy joints, significantly enhancing the imaging signals and minimizing its potential side effects. In vivo assays using both collagen-induced arthritis mice and acute arthritis mice demonstrate high performance and effectiveness in MR/CT dual-modal imaging of inflamed joints. This study provides insights into not only RA diagnosis in a more accurate manner but also the synthesis of multifunctional nanoprobes in a more robust and mild manner.