纳米型含碘造影剂的研究进展

碘制剂是X射线计算机断层扫描(CT)常用的造影剂,已广泛用于临床影像诊断。其中纳米型含碘造影剂具有良好的血池效应及低肾毒性。文章就近年来纳米型碘造影剂的发展及研究现状进行了综述。     

新型碘造影剂STL-05的合成

以3-氨基-5-(2,3-二乙酰氧基正丙胺基甲酰基)-2,4,6-三碘苯甲酸为原料,依次经氨基酰化、酰氯化、胺解和酯水解等4步反应得到标题化合物,结构经1HNMR和MS确证,其纯度≥98％(HPLC归一化法).标题化合物理化性质优于碘海醇,值得进一步评价.     

碘代X射线造影剂检测与去除工艺的研究进展

近年来碘代X射线造影剂(ICMs)在水环境中被广泛检出,且被证明是碘化消毒副产物的前体物。ICMs结构稳定,无法被常规水处理工艺有效去除。综述了ICMs在国内外水环境中的污染现状,介绍了ICMs的几种检测方法及特点,重点总结了ICMs的去除工艺,包括传统水处理技术和高级氧化技术,最后对ICMs今后的研究工作进行展望。     

靶向性磁共振成像造影剂的研究进展

综述了靶向性磁共振成像造影剂的研究进展,着重介绍了近年来在设计与合成具有靶向给药功能造影剂的研究概况,分别列出了亲脂性基团、VB6族化合物及其衍生物、糖类等功能基团作为靶向基团的水溶性顺磁性造影剂的配体结构。     

碘代X射线造影剂的污染现状及去除工艺研究进展

总结了新兴污染物ICM在污水、地表水和饮用水等各种水环境中的污染现状及相应的生态风险;介绍了现有的ICM的去除工艺,包括高级氧化技术、辐射技术及生物降解转化技术等;讨论了ICM自身及其转化产物消毒副产物对环境的生态风险。认为目前对于各种水体中ICM含量、准确测定、有效去除及毒性评估方面还存在一定的问题。后续应着重研究污水、饮用水消毒过程中ICM形成I-DBP的机理,研究有效的去除ICM的工艺技术,尤其是去除惰性离子型ICM的处理工艺,从源头控制ICM,避免ICM形成I-DBP的危害。     

三嗪基多孔有机聚合物的合成及碘吸附性能研究

核工业废料中放射性碘的富集严重威胁着人类的身体健康.因此,近年来高效捕获碘的材料的开发备受科研人员的关注.三嗪基多孔有机材料因其高的稳定性、特殊的化学结构,是一类具有广泛应用前景的多孔有机聚合物材料.采用廉价易得的三聚氯氰和4,4'-二氨基联苯通过一锅法且无催化剂的亲核取代反应制备了一种具有π-π 共轭结构的三嗪基多孔...     

碘普罗胺的专利合成路线浅谈

碘普罗胺是一种在临床上应用广泛的碘造影剂。本文先介绍了碘普罗胺的重要性,再从国内和国外两个角度分析了专利中其合成工艺路线,重点讨论了不同合成路线的特点和优劣,并进行了比较和总结。     

碘代丙炔基正丁氨基甲酸酯的合成研究

以正丁胺为原料,与光气合成正丁基异氰酸酯,再与2-丙炔-1-醇反应得2-丙炔基正丁氨基甲酸酯,最后与一氯化碘反应得碘代丙炔基正丁氨基甲酸酯。研究了物料配比、反应温度及催化剂选择对反应结果的影响,产品含量达99%以上,产品总收率达93%(以2-丙炔-1-醇计,n/n),此工艺适宜于工业化。     

纳米级超声造影剂的理论研究进展

为了克服超声造影剂中微米级气泡尺寸较大的局限性,大量研究人员对超声应用的替代造影剂(纳米级造影剂)进行了研究。随着生物纳米技术的飞速发展,纳米级超声造影剂在诊断与治疗领域有着广阔的发展前景。与超声造影剂中的微米级气泡相比,纳米级造影剂粒径较小,渗透能力极强,可以通过血管内皮间隙,进而可以实现血管外病变部位的显影。文中详细论述了超声造影剂在超声作用下的行为以及2种主要的纳米级造影剂:纳米气泡和纳米液滴造影剂,对其理论研究进展进行了总结,并提出了目前仍存在的一些问题及其未来的研究方向。     

果胶基口服结肠靶向给药系统的研究进展

果胶具有安全无毒、可生物降解和良好的生物相容性等特点成为药物缓释载体的常用材料.简要综述了果胶基口服结肠靶向给药系统的研究进展,并对其发展趋势进行了展望.     

基于表面活性剂的微泡型超声造影剂

综述了可用于超声造影剂微泡的表面活性剂的材料及制备方法,介绍了形成表面活性剂微泡中的气体材料的选择及其于表面活性剂类微泡超声造影剂。     

Ingestible Contrast Agents for Gastrointestinal Imaging

Gastrointestinal (GI) ailments cover a wide variety of diseases involving the esophagus, stomach, small intestine, large intestine, and rectum. They bring about many inconveniences in daily life in chronic diseases and can even be life threatening in acute cases. Rapid and safe detection approaches are essential for early diagnosis and timely management. Contrast agents for GI imaging can enhance contrast to distinguish abnormal lesions from normal structures. Computed tomography and magnetic resonance imaging are two important diagnostic tools for the evaluation of GI conditions. This review mainly involves several common GI diseases, including inflammatory diseases, intestinal tumors, diarrhea, constipation, and gastroesophageal reflux diseases. Selected contrast agents, such as barium sulfate, iodine-based agents, gadolinium-based agents, and others, are summarized. Going forward, continued endeavors are being made to develop more emerging contrast agents for other imaging modalities.     

Polydisulfide Based Biodegradable Macromolecular Magnetic Resonance Imaging Contrast Agents

Macromolecular Gd(III) complexes are advantageous over small molecular Gd(III) complexes in contrast enhanced magnetic resonance imaging (MRI) because of their prolonged blood circulation and preferential tumor accumulation. However, macromolecular contrast agents have not been approved for clinical applications because of the safety concerns related to their slow body excretion. Polydisulfide Gd(III) complexes have been designed and developed as biodegradable macromolecular MRI contrast agents to alleviate the concerns by facilitating the clearance of Gd(III) complexes from the body. These agents initially behave as macromolecular agents and result in superior contrast enhancement in the vasculature and tumor tissues. They can then be readily degraded in vivo into small molecular chelates that can rapidly excrete from the body via renal filtration after the MRI examinations. Various polydisulfide Gd(III) complexes have been prepared as biodegradable macromolecular MRI contrast agents. These agents have resulted in strong contrast enhancement in the vasculature and tumor tissue in animal models with minimal long-term tissue accumulation comparable to small molecular contrast agents. Polydisulfide Gd(III) complexes are promising for further clinical development as safe and effective biodegradable macromolecular MRI contrast agents for cardiovascular and cancer imaging. The review summarizes the chemistry and properties of polydisulfide Gd(III) complexes.     

Contrast Agents for Photoacoustic and Thermoacoustic Imaging: A Review

Photoacoustic imaging (PAI) and thermoacoustic imaging (TAI) are two emerging biomedical imaging techniques that both utilize ultrasonic signals as an information carrier. Unique advantages of PAI and TAI are their abilities to provide high resolution functional information such as hemoglobin and blood oxygenation and tissue dielectric properties relevant to physiology and pathology. These two methods, however, may have a limited detection depth and lack of endogenous contrast. An exogenous contrast agent is often needed to effectively resolve these problems. Such agents are able to greatly enhance the imaging contrast and potentially break through the imaging depth limit. Furthermore, a receptor-targeted contrast agent could trace the molecular and cellular biological processes in tissues. Thus, photoacoustic and thermoacoustic molecular imaging can be outstanding tools for early diagnosis, precise lesion localization, and molecular typing of various diseases. The agents also could be used for therapy in conjugation with drugs or in photothermal therapy, where it functions as an enhancer for the integration of diagnosis and therapy. In this article, we present a detailed review about various exogenous contrast agents for photoacoustic and thermoacoustic molecular imaging. In addition, challenges and future directions of photoacoustic and thermoacoustic molecular imaging in the field of translational medicine are also discussed.     

Ultrasound-Based Molecular Imaging of Tumors with PTPmu Biomarker-Targeted Nanobubble Contrast Agents

Ultrasound imaging is a widely used, readily accessible and safe imaging modality. Molecularly-targeted microbubble- and nanobubble-based contrast agents used in conjunction with ultrasound imaging expand the utility of this modality by specifically targeting and detecting biomarkers associated with different pathologies including cancer. In this study, nanobubbles directed to a cancer biomarker derived from the Receptor Protein Tyrosine Phosphatase mu, PTPmu, were evaluated alongside non-targeted nanobubbles using contrast enhanced ultrasound both in vitro and in vivo in mice. In vitro resonant mass and clinical ultrasound measurements showed gas-core, lipid-shelled nanobubbles conjugated to either a PTPmu-directed peptide or a Scrambled control peptide were equivalent. Mice with heterotopic human tumors expressing the PTPmu-biomarker were injected with PTPmu-targeted or control nanobubbles and dynamic contrast-enhanced ultrasound was performed. Tumor enhancement was more rapid and greater with PTPmu-targeted nanobubbles compared to the non-targeted control nanobubbles. Peak tumor enhancement by the PTPmu-targeted nanobubbles occurred within five minutes of contrast injection and was more than 35% higher than the Scrambled nanobubble signal for the subsequent two minutes. At later time points, the signal in tumors remained higher with PTPmu-targeted nanobubbles demonstrating that PTPmu-targeted nanobubbles recognize tumors using molecular ultrasound imaging and may be useful for diagnostic and therapeutic purposes.     

Ligand-Specific Nano-Contrast Agents Promote Enhanced Breast Cancer CT Detection at 0.5 mg Au

For many cancer types, being undetectable from early symptoms or blood tests, or often detected at late stages, medical imaging emerges as the most efficient tool for cancer screening. MRI, ultrasound, X-rays (mammography), and X-ray CT (CT) are currently used in hospitals with variable costs. Diagnostic materials that can detect breast tumors through molecular recognition and amplify the signal at the targeting site in combination with state-of-the-art CT techniques, such as dual-energy CT, could lead to a more precise detection and assist significantly in image-guided intervention. Herein, we have developed a ligand-specific X-ray contrast agent that recognizes α5β1 integrins overexpressed in MDA-MB-231 breast cancer cells for detection of triple (−) cancer, which proliferates very aggressively. In vitro studies show binding and internalization of our nanoprobes within those cells, towards uncoated nanoparticles (NPs) and saline. In vivo studies show high retention of ~3 nm ligand-PEG-S-AuNPs in breast tumors in mice (up to 21 days) and pronounced CT detection, with statistical significance from saline and iohexol, though only 0.5 mg of metal were utilized. In addition, accumulation of ligand-specific NPs is shown in tumors with minimal presence in other organs, relative to controls. The prolonged, low-metal, NP-enhanced spectral-CT detection of triple (−) breast cancer could lead to breakthrough advances in X-ray cancer diagnostics, nanotechnology, and medicine.     

Biocompatible Polyhydroxyethylaspartamide-based Micelles with Gadolinium for MRI Contrast Agents

Biocompatible poly-[N-(2-hydroxyethyl)-d,l-aspartamide]-methoxypoly(ethyleneglycol)-hexadecylamine (PHEA-mPEG-C₁₆) conjugated with 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid-gadolinium (DOTA-Gd) via ethylenediamine (ED) was synthesized as a magnetic resonance imaging (MRI) contrast agent. Amphiphilic PHEA-mPEG-C₁₆-ED-DOTA-Gd forms micelle in aqueous solution. All the synthesized materials were characterized by proton nuclear magnetic resonance (¹H NMR). Micelle size and shape were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM). Micelles with PHEA-mPEG-C₁₆-ED-DOTA-Gd showed higher relaxivities than the commercially available gadolinium contrast agent. Moreover, the signal intensity of a rabbit liver was effectively increased after intravenous injection of PHEA-mPEG-C₁₆-ED-DOTA-Gd.