Bismuth chelate as a contrast agent for X-ray computed tomography

Abstract

Backgrounds: Due to the unexpected side effects of the iodinated contrast agents, novel contrast agents for X-ray computed tomography (CT) imaging are urgently needed. Nanoparticles made by heavy metal elements are often employed, such as gold and bismuth. These nanoparticles have the advantages of long in vivo circulation time and tumor targeted ability. However, due to the long residence time in vivo, these nanoparticles may bring unexpected toxicity and, the preparation methods of these nanoparticles are complicated and time-consuming. Methods: In this investigation, a small molecular bismuth chelate using diethylenetriaminepentaacetic acid (DPTA) as the chelating agent was proposed to be an ideal CT contrast agent. Results: The preparation method is easy and cost-effective. Moreover, the bismuth agent show better CT imaging for kidney than iohexol in the aspect of improved CT values. Up to 500 µM, the bismuth agent show negligible toxicity to L02 cells and negligible hemolysis. And, the bismuth agent did not induce detectable morphology changes to the main organs of the mice after intravenously repeated administration at a high dose of 250 mg/kg. The pharmacokinetics of the bismuth agent follows the first-order elimination kinetics and, it has a short half-life time of 0.602 h. The rapid clearance from the body promised its excellent biocompatibility. Conclusions: This bismuth agent may serve as a potential candidate for developing novel contrast agent for CT imaging in clinical applications.

One stone, many birds: Recent advances in functional nanogels for cancer nanotheranostics

“…In comparison, metal-free organic CAs display significant superiority, such as functionality, relatively low toxicity, improved pharmacokinetics, and favorable biodistribution (Akakuru et al, 2019). According to different contrast mechanisms, they could be divided into organic radical, chemical exchange saturation transfer, and heteronuclear CAs (Fu, Yu, et al, 2020). For instance, 19 F, as a heteronuclear atom, has been widely studied to overcome the limitations of the traditional 1 H MRI technique, due to the considerably high MR sensitivity (83% of the 1 H protons) without background signal from the body, a broad range of chemical shift (>350 ppm), 100% natural abundance and nuclear spin of 1/2 (Ahrens & Bulte, 2013;Dolbier, 2008;Tirotta et al, 2015;Wolters et al, 2013).…”

“…On the one hand, as most of the CAs for bioimaging and sensitizers are of metallic nature, the effective combination of NGs and inorganic molecules can significantly improve theranostic efficacy (Sierra-Martin & Fernandez-Barbero, 2015;. On the other hand, organic molecules for bioimaging or as sensitizers gradually knock the door of tumor theranostic, addressing the side effects of the poor metabolism of the metal-based compound inside the body (Chen et al, 2013;Fu, Yu, et al, 2020). In this review, we focus on the recent advances of functional NGs in cancer nanotheranostics.…”

Biocompatible carbonized iodine-doped dots for contrast-enhanced CT imaging

“…For example, patients with iodine-based contrast agent injection showed an increased risk of worsened renal impairment and a significant effect on the development of post-CT acute kidney injury [ 11 – 13 ]. In addition, some CT contrast agents induce adverse cardiac events, such as cardiac death and heart failure, within one month after CT contrast agent administration [ 14 , 15 ]. To overcome these limitations, studies on contrast agents with high K-edge energy, such as polymers, gold nanoparticles, gadolinium, and bismuth, are being conducted; however, these contrast agents are also not free from low solubility and safety problems [ 16 – 21 ].…”

Facile Fabrication of BiF3: Ln (Ln = Gd, Yb, Er)@PVP Nanoparticles for High-Efficiency Computed Tomography Imaging

“…X-ray computed tomography (CT) can image internal tissues and organs in a cross-sectional way with high resolution and low price [1,2]. Thus, it is an important means to diagnose respiratory diseases, digestive diseases, and urinary system diseases [3][4][5][6][7][8]. However, CT sometimes has low contrast between diseased tissues and normal tissues.…”

“…It has been used in clinical practice and plays a critical role in combination therapy for Helicobacter pylori and other diseases, including chronic liver disease as well as gastric and duodenal ulcers. It has great biological safety and tolerance during treatment [7,25]. Also, Bi has been used in the preparation of nanoscale contrast agents such as HA-BiO NPs, Bi 2 S 3 , BION, and Bi 2 Te 3 because of its high atomic number (Z = 83) and excellent X-ray attenuation capacity (5.74 cm 2 kg −1 at 100 keV) [26][27][28][29].…”