High-performance hepatobiliary dysprosium contrast agent for ultra-high-field magnetic resonance imaging

Flavonoid-Conjugated Gadolinium Complexes as Anti-Inflammatory Theranostic Agents

In this study, we designed, synthesized, and evaluated gadolinium compounds conjugated with flavonoids as potential theranostic agents for the treatment of inflammation. These novel theranostic agents combine a molecular imaging agent and one of three flavonoids (galangin, chrysin, and 7-hydroxyflavone) as anti-inflammatory drugs as a single integrated platform. Using these agents, MR imaging showed contrast enhancement (>10 in CNR) at inflamed sites in an animal inflammation model, and subsequent MR imaging used to monitor the therapeutic efficacy of these integrated agents revealed changes in inflamed regions. The anti-inflammatory effects of these agents were demonstrated both in vitro and in vivo. Furthermore, the antioxidant efficacy of the agents was evaluated by measuring their reactive oxygen species scavenging properties. For example, Gd-galangin at 30 μM showed a three-fold higher ROS scavenging of DPPH. Taken together, our findings provide convincing evidence to indicate that flavonoid-conjugated gadolinium compounds can be used as potentially efficient theranostic agents for the treatment of inflammation.

Outstanding MRI contrast with dysprosium phosphate nanoparticles of tuneable size

The use of high-field magnets for magnetic resonance imaging (MRI) is expected to experience the fastest growth rate during the present decade. Although several CAs for MRI scanners using high magnetic fields have been reported, they are mostly based on fluoride matrices, which are known for their low chemical stability in aqueous suspensions. Chemically stable MRI CAs for high-field magnets are therefore needed to enable the advances in MRI technique. Herein, we synthesized uniform DyPO₄ nanoparticles (NPs) with tuneable sizes between 23 and 57 nm using homogeneous precipitation in butanol. The NPs were successfully functionalized with polyacrylic acid (PAA) and showed good colloidal stability in aqueous suspensions. Chemical stability was also assessed in PBS, showing negligible solubility. The effect of particle size on the transversal relaxivity value (r₂) was further explored at 9.4 T, finding a clear increase in r₂ with particle size. The r₂ value found for the largest NPs was 516 mM^-1 s^-1, which is, to the best of our knowledge, the highest r₂ value ever reported at 9.4 T for any Dy-based nanometric particles in the literature. Finally, the latter NPs were submitted to biosafety studies after polyethylene glycol (PEG) functionalization. Cell morphology, induction of necrotic/late apoptotic cells, and mitochondrial activity were thoroughly analyzed. The results clearly indicated negligible toxicity effects under the assayed conditions. Short- and long-term in vivo pharmacokinetics of the intravenously injected NPs were assessed by dynamic T₂-weighted MRI and quantitative T₂ mapping, revealing faster liver than spleen uptake, while no accumulation was observed in the kidneys. Finally, no histopathological changes were observed in any of the studied organs, including the liver, kidney, spleen, and lung, which provide further evidence of the biocompatibility of DyPO₄ NPs and, therefore, their suitability as bioimaging probes.

Intrinsically radiopaque biomaterial assortments: a short review on the physical principles, X-ray imageability, and state-of-the-art developments

X-ray attenuation ability, otherwise known as radiopacity of a material, could be indisputably tagged as the central and decisive parameter that produces contrast in an X-ray image. Radiopaque biomaterials are vital in the healthcare sector that helps clinicians to track them unambiguously during pre and post interventional radiological procedures. Medical imaging is one of the most powerful resources in the diagnostic sector that aids improved treatment outcomes for patients. Intrinsically radiopaque biomaterials enable themselves for visual targeting/positioning as well as to monitor their fate and further provide the radiologists with critical insights about the surgical site. Moreover, the emergence of advanced real-time imaging modalities is a boon to the contemporary healthcare systems that allow to perform minimally invasive surgical procedures and thereby reduce the healthcare costs and minimize patient trauma. X-ray based imaging is one such technologically upgraded diagnostic tool with many variants like digital X-ray, computed tomography, digital subtraction angiography, and fluoroscopy. In light of these facts, this review is aimed to briefly consolidate the physical principles of X-ray attenuation by a radiopaque material, measurement of radiopacity, classification of radiopaque biomaterials, and their recent advanced applications.

Understanding Rare Earth Elements concentrations, anomalies and fluxes at the river basin scale: The Moselle River (France) as a case study

Anthropogenic activities linked to various new technologies are increasingly disrupting REEs biogeochemical cycles. A catchment-based perspective is therefore necessary to distinguish between natural (i.e., changes in lithology) and human-related sources of REEs variability. In the present study, REEs patterns, anomalies and fluxes were investigated in the French part of the Moselle River basin (Moselle River itself and some of its headstreams and tributaries). The REEs patterns in the headstream waters were highly variable and mostly related to the complex underlying lithology (granite, sandstone, tuff and graywacke). Along the Moselle River, the presence of positive Gd anomalies and a regular LREEs depletion/HREEs enrichment pattern on sandstone/limestone substrates were the most distinctive features. The Gd anomaly varied from 1.8 to 8.7, with anthropogenic Gd representing 45 to 88% of the total Gd. A linear relationship was obtained between the anthropogenic Gd flux and the cumulative population along the watershed. However, the magnitude of the Gd anomalies was shown to depend on the methodological approach chosen for their calculation. The use of a threshold value to identify the presence of an anthropogenic Gd anomaly may therefore be basin (and lithology) dependent, and care has to be taken in comparing results from different rivers or lithologies. Concentration of anthropogenic Gd in the Moselle River and its tributaries were close to, or above, the value of 20 ng/L reported in literature to elicit adverse biological effects in laboratory cell cultures. The ecotoxicological significance of Gd anomalies deserves further investigation because concentrations of anthropogenic Gd may also vary depending on the methodological approach used for calculating Gd anomalies.