Noninvasive In Vivo Imaging of T-Cells during Cancer Immunotherapy Using Rare-Earth Nanoparticles

Only a minority of patients respond positively to cancer immunotherapy, and addressing this variability is an active area of immunotherapy research. Infiltration of tumors by immune cells is one of the most significant prognostic indicators of response and disease-free survival. However, the ability to noninvasively sample the tumor microenvironment for immune cells remains limited. Imaging in the near-infrared-II region using rare-earth nanocrystals is emerging as a powerful imaging tool for high-resolution deep-tissue imaging. In this paper, we demonstrate that these nanoparticles can be used for noninvasive in vivo imaging of tumor-infiltrating T-cells in a highly aggressive melanoma tumor model. We present nanoparticle synthesis and surface modification strategies for the generation of small, ultrabright, and biocompatible rare-earth nanocrystals necessary for deep tissue imaging of rare cell types. The ability to noninvasively monitor the immune contexture of a tumor during immunotherapy could lead to early identification of nonresponding patients in real time, leading to earlier interventions and better outcomes.

Fabrication of tumor targeting rare-earth nanocrystals for real-time NIR-IIb fluorescence imaging-guided breast cancer precise surgery

The near-infrared fluorescence imaging has been integrated into the operating room to guide tumor resection, potentially reducing the positive margin rates in breast-conserving surgery (BCS). Relative to the widely used first near-infrared fluorescence imaging, imaging in the second near-infrared (NIR-II) region possesses higher contrast and deeper tissue penetration, particularly in the NIR-IIb window, offering many new opportunities for imaging-guided BCS. Here, we fabricated the c(RGDfC) functionalized erbium-based rare-earth nanoparticles (ErNPs@cRGD) with superior optical property in NIR-IIb region. Owing to deeper tissue penetration and efficient tumor targeting, ErNPs@cRGD-based NIR-IIb fluorescence imaging achieved enhanced signal-to-background ratios in tumor visualization, which was able to guide more complete tumor resection, identify multiple microtumors and distinguish malignant lesions from normal tissues in various mice models. Based on these, this NIR-IIb imaging strategy for surgical navigation can significantly reduce positive margin rates and improve prognosis, laying a foundation for the clinical resection of breast cancer.

Rare-earth nanoparticles induce depression, anxiety-like behavior, and memory impairment in mice

Rare-earth nanoparticles have been widely studied for disease diagnosis, in vivo optical imaging, biosensing, and drug delivery. However, the effects of rare-earth nanoparticles on a central nervous system remain unclear. Here, we report that the continuous exposure to rare-earth nanoparticles in mice can cause behavioral alterations including cognitive deficits, anxiety, and depression-like behavior. Using an open-field test and a morris water maze, we showed that long-term exposure to rare-earth nanoparticles may lead to significant depression, anxiety-like behavior, and memory impairment. The histopathological investigation on the neurotoxicological effects of nanoparticles indicated a significant decrease in cell viability after seven days' nanoparticle exposure. Western blotting analysis suggested that the changes of ATP-citrate lyase (ACLY) and O-linked N-acetylglucosamine transferase (OGT, a unique glycosyltransferase enzyme) played important roles in neurobehavioral disorders in mice. These findings provide a pathway to understand the cytotoxicity of rare-earth nanoparticles for medial applications and offer insights into the risk of these nanoparticles in biological systems.