Bismuth nanomaterials as contrast agents for radiography and computed tomography imaging and their quality/safety considerations.

Contrast agents for radiography and computed tomography (CT) scans are substances that can enhance the contrast of blood vessels and soft tissue with detailed imaging information of the diseased sites. However, the large doses, short circulation time and adverse effects are the intrinsic limitations of CT contrast agents, preventing their extended and safe use in the clinical setting. Bismuth nanoparticles (NPs) have gained attention for the high X-ray absorption of bismuth elements with acceptable biocompatibility, showing their potential to be translated into commercialized CT contrast agents. Compared with traditional iodine contrast agents, bismuth NPs are characterized by prolonged circulation time and enhanced contrast, largely due to the surface modification and enhanced permeability and retention effect of NPs. Bismuth NPs can also be flexibly upgraded into sophisticated nanoagents for multimodal imaging and therapeutic purposes by complexation with supporting chemicals, small molecule drugs, fluorescence labels, and other functional agents. Additionally, the affinity and retention of the bismuth NPs in the diseased sites can be further improved by modification of the targeting moiety on the NPs surface. However, a simple synthetic process and low complexity of bismuth NPs are highly recommended for scaling out and quality control of nanoagents with commercialization potential. Since product safety is a prerequisite for the translation of bismuth NPs from bench to the clinic, we focus on recent advances in the distribution, elimination, and toxicity of bismuth NPs previously reported. Finally, we delineate the associated mechanisms for nephrotoxicity and the strategy to reduce the toxicity of bismuth NPs. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials.

[Study on potential hepatotoxicity of main monomers of Polygonum multiflorum based on liver micro-tissue].

In this study, we aimed to establish a rat liver micro-tissue evaluation system to evaluate the hepatotoxicity of the main monomers in Polygonum multiflorum. Rat primary hepatocytes were isolated and purified by two-step in situ perfusion method to prepare hepatic parenchymal cells. The ultra-low adsorption plate and the inverted model were used to establish an in vitro hepatotoxicity evaluation system. After the system was established, the main monomer components(monanthone with emodin type, rhein, emodin, emodin-8-O-ß-D-glucopyranoside, physcion) of P. multiflorum were selected for in vitro hepatotoxicity evaluation. This study showed that the primary cells of the liver can form liver micro-tissues in the low adsorption plate method and the mold perfusion method, with good liver structure and function, which can be used to evaluate the hepatotoxicity of the drug to be tested after long-term administration. The five monomers to be tested in P. multiflorum can significantly affect the proliferation of primary liver micro-tissues in rats in a dose-and time-dependent manner. The hepatotoxic effects were as follows: monanthone with emodin type > rhein > emodin > emodin-8-O-ß-D-glucopyranoside > physcion. The results suggested that the emodin-type monoterpene and rhein might be the potential hepatotoxic components, while the metabolites of emodin-8-O-ß-D-glucoside and emodin methyl ether showed more toxic risks. The rat primary hepatocyte micro-tissue model system established in this experiment could be used to achieve long-term drug administration in vitro, which was consistent with the clinical features of liver injury caused by long-term use of P. multiflorum. The experimental results provided important information and reference on the clinical application and toxic component of P. multiflorum.