Small-Molecule Bi-DOTA Complex for High-Performance CT and Spectral CT Bioimaging

Bismuth Chelate-Mediated Digital Subtraction Angiography

Digital subtraction angiography (DSA) is considered the "gold standard" for the diagnosis of vascular diseases. However, the contrast agents used in DSA are limited to iodine (I)-based small molecules, which are unsuitable for patients with contraindications. Here, iodine-free DSA utilizing a bismuth (Bi) chelate, Bi-DTPA Dimeglumine, is proposed for vascular visualization for the first time. Bi-DTPA Dimeglumine possesses a simple synthesis process without the need for purification, large-scale production ability (over 200 g in the lab), superior X-ray imaging capability, renal clearance capacity, and good biocompatibility. Bi-DTPA-enhanced DSA can clearly display the arteries of the rabbit's head and lower limbs, with a minimum vascular resolution of 0.5 mm. The displayed integrity of terminal vessels by Bi-DTPA-enhanced DSA is superior to that of iopromide-enhanced DSA. In a rabbit model of thrombotic disease, Bi-DTPA Dimeglumine-enhanced DSA enables the detection of embolism and subsequent reevaluation of vascular conditions after recanalization therapy. This proposed iodine-free DSA provides a promising and universal approach for diagnosing vascular diseases.

Hybrid FeWO4-Hyaluronic Acid Nanoparticles as a Targeted Nanotheranostic Agent for Multimodal Imaging-Guided Tumor Photothermal Therapy

Background

Development of versatile nanoplatform still remains a great challenge due to multistep synthesis and complicated compositions. Therefore, it is significant to develop a facile method to synthesize a nanocomposite to achieve multimodal imaging and even imaging-guided cancer therapeutics.

Methods and Results

In our study, hyaluronic acid-functionalized iron (II) tungstate nanoparticles (HA-FeWO4 NPs) were successfully synthesized as a versatile nanoplatform by a facile one-pot hydrothermal procedure. The formed multifunctional HA-FeWO4 NPs were investigated via a series of characterization techniques, which demonstrated good biocompatibility, excellent dispersion, low cytotoxicity, active tumor-targeting ability and high photothermal efficiency. Furthermore, tumor was clearly visualized by HA-FeWO4 NPs with multimodal imaging of infrared thermal imaging, magnetic resonance imaging, computed tomography imaging in 4T1 tumor bearing mice. More importantly, HA-FeWO4 could achieve multimodal imaging-guided photothermal therapy of 4T1 tumors.

Conclusion

The constructed HA-FeWO4 NPs have great potential as ideal nanotheranostic agents for multimodal imaging and even imaging-guided cancer theranostics in biological systems.

Achieving safe and high-performance gastrointestinal tract spectral CT imaging with small-molecule lanthanide complex

BACKGROUND

Non-intrusive imaging of gastrointestinal (GI) tract using computed tomography (CT) contrast agents is of the most significant issues in the diagnosis and treatment of GI diseases. Moreover, spectral CT, which can generate monochromatic images to display the X-ray attenuation characteristics of contrast agents, provides a better imaging sensitivity for diagnose inflammatory bowel disease (IBD) than convention CT imaging.

METHODS

Herein, a convenient and one-pot synthesis method is provided for the fabrication of small-molecule lanthanide complex Holmium-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (Ho-DOTA) as a biosafe and high-performance spectral CT contrast agent for GI imaging with IBD. In vivo CT imaging was administered with both healthy mice and colitis mice induced by dextran sodium sulfate.

RESULTS

We found that Ho-DOTA accumulated in inflammation sites of large intestines and produced high CT contrast compared with healthy mice. Both in vitro and in vivo experimental results also showed that Ho-DOTA provided much more diagnostic sensitivity and accuracy due to the excellent X-ray attenuation characteristics of Ho-DOTA compared with clinical iodinate agent. Furthermore, the proposed contrast media could be timely excreted from the body via the urinary and digestive system, keeping away from the potential side effects due to long-term retention in vivo.

CONCLUSION

Accordingly, Ho-DOTA with excellent biocompatibility can be useful as a potential high-performance spectral CT contrast agent for further clinical imaging of gastrointestinal tract and diagnosis of intestinal system diseases.