Contrast Agents For Medical Imaging Research Articles

Dopaminergic- and Serotonergic-Dependent Behaviors Are Altered by Lanthanide Series Metals in Caenorhabditis elegans

The lanthanide series elements are transition metals used as critical components of electronics, as well as rechargeable batteries, fertilizers, antimicrobials, contrast agents for medical imaging, and diesel fuel additives. With the surge in their utilization, lanthanide metals are being found more in our environment. However, little is known about the health effects associated with lanthanide exposure. Epidemiological studies as well as studies performed in rodents exposed to lanthanum (La) suggest neurological damage, learning and memory impairment, and disruption of neurotransmitter signaling, particularly in serotonin and dopamine pathways. Unfortunately, little is known about the neurological effects of heavier lanthanides. As dysfunctions of serotonergic and dopaminergic signaling are implicated in multiple neurological conditions, including Parkinson’s disease, depression, generalized anxiety disorder, and post-traumatic stress disorder, it is of utmost importance to determine the effects of La and other lanthanides on these neurotransmitter systems. We therefore hypothesized that early-life exposure of light [La (III) or cerium (Ce (III))] or heavy [erbium (Er (III)) or ytterbium (Yb (III))] lanthanides in Caenorhabditis elegans could cause dysregulation of serotonergic and dopaminergic signaling upon adulthood. Serotonergic signaling was assessed by measuring pharyngeal pump rate, crawl-to-swim transition, as well as egg-laying behaviors. Dopaminergic signaling was assessed by measuring locomotor rate and egg-laying and swim-to-crawl transition behaviors. Treatment with La (III), Ce (III), Er (III), or Yb (III) caused deficits in serotonergic or dopaminergic signaling in all assays, suggesting both the heavy and light lanthanides disrupt these neurotransmitter systems. Concomitant with dysregulation of neurotransmission, all four lanthanides increased reactive oxygen species (ROS) generation and decreased glutathione and ATP levels. This suggests increased oxidative stress, which is a known modifier of neurotransmission. Altogether, our data suggest that both heavy and light lanthanide series elements disrupt serotonergic and dopaminergic signaling and may affect the development or pharmacological management of related neurological conditions.

Unravelling the ecotoxicological impacts of gadolinium (Gd) on Mytilus galloprovincialis embryos and sperm in seawater: A preliminary study

As the demand for rare earth elements (REEs) continues to surge in diverse industrial and medical domains, the ecological consequences of their ubiquitous presence have garnered heightened attention. Among the REEs, gadolinium (Gd), commonly used in medical imaging contrast agents, has emerged as a pivotal concern due to its inadvertent introduction into marine ecosystems via wastewater release. This study delves into the complex ecotoxicological implications of Gd contamination, focusing on its impact on the embryonic development and sperm functionality of Mytilus galloprovincialis. The findings from this study underscore the potential hazards posed by this rare element, offering a critical perspective on the ecological risks associated with Gd. Notably, this exploratory work reveals that Gd exerts a significant embryotoxic effect at elevated concentrations, with an observed half maximal effective concentration (EC50) value of 0.026 mg/L. Additionally, Gd exposure leads to a considerable reduction in sperm motility and alters sperm morfo-kinetic parameters, especially at a concentration of 5.6 mg/L. The results highlight a dose-dependent relationship between Gd exposure and the prevalence of specific malformation types in Mytilus embryos, further providing crucial insights into the potential risks imposed by this rare earth element.

Contrast medium: an unpredictable ally

Reactions to contrast media are unpredictable. This article examines the use of iodinated and gadolinium-based contrast agents in medical imaging. It explores their clinical presentation, associated risk factors, precautions prior to their administration, and treatment options in the event of a reaction. By highlighting these essential aspects, the article aims to inform healthcare professionals on the safe and effective management of these agents during imaging procedures. The effectiveness of the different premedication protocols proposed in the literature has not yet been established. In particular, premedication does not prevent serious allergic reactions.

Depolymerizing self-immolative polymeric lanthanide chelates for vascular imaging.

Medical imaging is widely used clinically and in research to understand disease progression and monitor responses to therapies. Vascular imaging enables the study of vascular disease and therapy, but exogenous contrast agents are generally needed to distinguish the vasculature from surrounding soft tissues. Lanthanide-based agents are commonly employed in MRI, but are also of growing interest for micro-CT, as the position of their k-edges allows them to provide enhanced contrast and also to be employed in dual-energy micro-CT, a technique that can distinguish contrast-enhanced blood vessels from tissues such as bone. Small molecule Gd3+ chelates are available, but are excreted too rapidly. At the same time, a lack of rapid clearance from the body for long-circulating agents presents toxicity concerns. To address these challenges, we describe here the use of self-immolative polymers for the development of new degradable chelates that depolymerize completely from end-to-end following the cleavage of a single end-cap from the polymer terminus. We demonstrate that tuning the end-cap allows the rate of depolymerization to be controlled, while tuning the polymer length enables the polymer to exhibit long circulation times in the blood of mice. After successfully providing one hour of blood contrast, depolymerization led to excretion of the resulting small molecule chelates into the bladder. Despite the high doses required for micro-CT, the agents were well tolerated in mice. Thus, these self-immolative polymeric chelates provide a new platform for the development of medical imaging contrast agents. STATEMENT OF SIGNIFICANCE: Vascular imaging is used clinically to diagnose and monitor vascular disease and in research to understand the progression of disease and study responses to new therapies. For techniques such as magnetic resonance imaging and x-ray computed tomography (CT), long circulating contrast agents are needed to differentiate the vasculature from surrounding tissues. However, if these agents are not rapidly excreted from the body, they can lead to toxicity. We present here a new polymeric system that can chelate hundreds of lanthanide ions for imaging contrast and can circulate for one hour in the blood, but then after end-cap cleavage breaks down completely into small molecules for excretion. The successful application of this system in micro-CT in mice is demonstrated.

Preparation Method and Application of Nanobubbles: A Review

Nanobubbles represent a special colloidal system, as they have high stability and large specific surface areas. The preparation of nanobubbles is currently a hot research topic, as it crucial to investigate their characteristics and expand their applications. This article explains the mechanism of generating nanobubbles based on chemical and physical methods, introduces their basic composition’s structure and properties, summarizes the methods of preparing bulk nanobubbles (BNBs) and surface nanobubbles (SNBs), and clarifies the preparation principles and techniques. Seven practical applications of nanobubbles are cited in this paper, including their use as ultrasonic contrast agents in medical imaging, drug delivery systems in drug transportation, promoters of plant growth by affecting plant respiration and water absorption at the roots, tools to remove dirt from surfaces by generating energy during nanobubble bursting, producers of high-density negative ions and free radicals to react with pollutants in wastewater, tools to reduce the resistance of the fluid flow through channels by lowering the internal friction, and means of improving the mineral flotation recovery rate by enhancing the absorption capacity of bubbles to minerals. Finally, the future development of nanobubble preparation technology is discussed, including their roles in optimizing equipment and preparation methods; improving the quantity, efficiency, stability, controllability, and homogeneity of nanobubble generation; and promoting the industrial production of nanobubbles.

A Review of the Preparation, Characterization, and Applications of Chitosan Nanoparticles in Nanomedicine.

Chitosan is a fibrous compound derived from chitin, which is the second most abundant natural polysaccharide and is produced by crustaceans, including crabs, shrimps, and lobsters. Chitosan has all of the important medicinal properties, including biocompatibility, biodegradability, and hydrophilicity, and it is relatively nontoxic and cationic in nature. Chitosan nanoparticles are particularly useful due to their small size, providing a large surface-to-volume ratio, and physicochemical properties that may differ from that of their bulk counterparts; thus, chitosan nanoparticles (CNPs) are widely used in biomedical applications and, particularly, as contrast agents for medical imaging and as vehicles for drug and gene delivery into tumors. Because CNPs are formed from a natural biopolymer, they can readily be functionalized with drugs, RNA, DNA, and other molecules to target a desired result in vivo. Furthermore, chitosan is approved by the United States Food and Drug Administration as being Generally Recognized as Safe (GRAS). This paper reviews the structural characteristics and various synthesis methods used to produce chitosan nanoparticles and nanostructures, such as ionic gelation, microemulsion, polyelectrolyte complexing, emulsification solvent diffusion, and the reverse micellar method. Various characterization techniques and analyses are also discussed. In addition, we review drug delivery applications of chitosan nanoparticles, including for ocular, oral, pulmonary, nasal, and vaginal methodologies, and applications in cancer therapy and tissue engineering.

Fluorinated hydrogel nanoparticles with regulable fluorine contents and T2 relaxation times as 19F MRI contrast agents.

Medical imaging contrast agents that are able to provide detailed biological information have attracted increasing attention. Among the new emerging imaging contrast agents, 19F magnetic resonance imaging contrast agents (19F MRI CAs) are extremely promising for their weak background disturbing signal from the body. However, to prepare 19F MRI CAs with a long T2 relaxation time and excellent biocompatibility in a simple and highly effective strategy is still a challenge. Herein, we report a new type of 19F MRI hydrogel nanocontrast agents (19F MRI HNCAs) synthesized by a surfactant-free emulsion polymerization with commercial fluorinated monomers. The T2 relaxation time of 19F MRI HNCA-1 was found to be 25-40 ms, guaranteeing its good imaging ability in vitro. In addition, according to an investigation into the relationship between the fluorine content and 19F MRI signal intensity, the 19F MRI signal intensity was not only determined by the fluorine content in 19F MRI HNCAs but also by the hydration microenvironment around the fluorine atoms. Moreover, 19F MRI HNCAs demonstrated excellent biocompatibility and imaging capability inside cells. The primary exploration demonstrated that 19F MRI HNCAs as a new type of 19F MRI contrast agent hold potential for imaging lesion sites and tracking cells in vivo by 19F MRI technology.

Review: Application Trends of Contrast Media in PET/MRI

Research on medical imaging contrast agents to improve diagnostic performance and optimize treatment strategies has been ongoing for a long time. Recently, hybrid imaging technology in which two different devices such as PET/CT, SPECT/CT, and PET/MRI are fused is emerging as a new trend in medical imaging. The high spatial resolution of Magnetic Resonance Imaging (MRI) and the high-sensitivity molecular-level information of Positron Emission Tomography (PET) by these convergence devices are leading to the development of new hybrid imaging technologies along with hybrid contrast agents. To create a hybrid contrast agent for simultaneous PET-MRI devices, the radiotracer for PET should be combined with the MRI contrast agent. The most common approach to achieve this is to coat radioisotopes to the surface of small superparamagnetic iron oxide (SPIO) particles. These contrast agents are used for pH change monitoring, non-invasive angiography, and early imaging diagnosis of atherosclerosis. In addition, tumor detection and cardiovascular imaging are becoming important research areas for the development of simultaneous PET/MRI imaging systems and hybrid contrast agents. Therefore, tumor detection and cardiovascular imaging are major areas for development of simultaneous PET/MRI imaging systems and hybrid contrast agents. The goal of developing hybrid contrast agents for this purpose is to combine high spatial resolution, high sensitivity, and morphological and functional information. The future prospect is considered to be the development of a multimodal hybrid contrast agent that detects diseases early, provides information before and after surgery for treatment, and provides treatment prognosis.

Riparian Dendrochemistry: Detecting Anthropogenic Gadolinium in Trees along an Effluent-Dominated Desert River

This research documents spatial and temporal patterns of effluent uptake by riparian trees through development of a new and innovative application for dendrochronology, specifically dendrochemistry. The rare-earth element (REE) gadolinium (Gd) is a known micro-pollutant in its anthropogenic form and enters streams from wastewater treatment plants. Anthropogenic Gd was first used in select medical procedures in 1988 and has since been used as a contrast agent for medical imaging. It is naturally flushed from the body following procedures and is subsequently discharged via treatment plants into waterways. Riparian trees that utilize effluent-dominated surface water take up Gd, which then remains in annual growth rings. The year 1988 serves as presence/absence date stamp for Gd in tree rings, thereby making Gd an ideal marker for this dendrochronological study. Results from this study along the Upper Santa Cruz River in southeastern Arizona show levels of Gd in effluent-dominated surface flows to be elevated above the threshold that distinguishes an anthropogenic anomaly from natural GdSN abundance in freshwater, thereby confirming that anthropogenic Gd is present. Gd was found in the growth rings of cottonwood trees (Populus fremontii var. arizonica (Sarg.) Jeps.) that are growing in the floodway adjacent to the effluent-dominated portion of the stream. The presence of Gd in cottonwood annual rings confirms that the trees are utilizing effluent over the course of the growing season. Furthermore, temporal patterns of Gd concentrations in trees directly adjacent to the stream may be reflective of high-frequency changes in surface water quality. Information on the impacts of effluent quality on the chemical composition of tree rings can be a useful monitoring tool to evaluate the spatial and temporal patterns of effluent use in riparian trees and to identify high-frequency changes in surface water quality.

NIR-II Functional Materials for Photoacoustic Theranostics.

Photoacoustic imaging (PAI) has attracted great attention in the diagnosis and treatment of diseases due to its noninvasive properties. Especially in the second near-infrared (NIR-II) window, PAI can effectively avoid the interference of tissue spontaneous fluorescence and light scattering, and obtain high resolution images with deeper penetration depth. Because of its ideal spectral absorption and high conversion efficiency, NIR-II PA contrast agents overcome the absorption or emission of NIR-II light by endogenous biomolecules. In recent years, a series of NIR-II PA contrast agents have been developed to improve the performance of PAI in disease diagnosis and treatment. In this paper, the research progress of NIR-II PA contrast agents and their applications in biomedicine are reviewed. PA contrast agents are classified according to their composition, including inorganic contrast agents, organic contrast agents, and hybrid organic-inorganic contrast agents. The applications of NIR-II PA contrast agents in medical imaging are described, such as cancer imaging, inflammation detection, brain disease imaging, blood related disease imaging, and other biomedical application. Finally, the research prospects and breakthrough of NIR-II PA contrast agents are discussed.

Hybrid polymeric micelles stabilized by gallium ions: Structural investigation

The addition of gallium ions to a solution of a double-hydrophilic block copolymer, i.e. poly(ethylene oxide)-block-poly(acrylic acid), leads to the spontaneous formation of highly monodisperse micelles with a Hybrid PolyIon Complexes (HPICs) core. By combining several techniques, a precise description of the HPIC architecture was achieved. In particular and for the first time, NMR and anomalous small angle X-ray scattering (ASAXS) enable tracking of the inorganic ions in solution and highlighting the co-localization of the gallium and the poly(acrylic acid) blocks in a rigid structure at the core of the micelle. Such a core has a radius of ca 4.3 nm while the complete nano-object with its poly(ethylene oxide) shell has a total radius of ca 11 nm. The aggregation number was also estimated using the ASAXS results. This comprehensive structural characterization of the Ga HPICs corroborates the assumptions made for HPICs based on other inorganic ions and demonstrates the universality of the HPIC structure leading, for example, to new families of contrast agents in medical imaging.

Colloidally Stable Monodisperse Fe Nanoparticles as T2 Contrast Agents for High-Field Clinical and Preclinical Magnetic Resonance Imaging

Iron nanoparticles (Fe NPs) produce negative contrast in magnetic resonance imaging (MRI) by shortening the transverse relaxation time (T2) of water protons at tissue sites. The high sensitivity of Fe toward oxidation under ambient conditions has challenged and impeded the development of stable Fe NPs for bioapplications compared to iron oxide nanoparticles (IONPs). This article demonstrates the synthesis of three batches of fairly monodisperse (size dispersion, <10%), colloidal Fe NPs with inorganic core diameters of 15.2, 12.0, and 8.8 nm. The 15.2 nm Fe NPs show high stability against oxidation, beyond 5 months, when dispersed in chloroform and deionized water. Upon dispersion in deionized water, these NPs gradually develop an amorphous iron oxide shell. On the contrary, upon transfer into water, the smaller Fe NPs oxidize to amorphous iron oxide eventually. The 15.2 nm Fe NPs exhibit much stronger shortening of the T2 relaxation time compared to the 12.0 and 8.8 nm Fe NPs at both high-field clinical 3 T and preclinical 9.4 T. The transverse relaxivity (r2) values of the 15.2 nm Fe NPs, based on per Fe ion concentration, were determined to be 167.9 mM–1 s–1 at 3 T and 236.4 mM–1 s–1 (higher than similarly sized IONPs) at 9.4 T. The respective r2/r1 ratios of 280 and 788 are high for a T2 contrast agent, although comprehensive MRI data for Fe NPs are not available in the literature for direct comparison. Fe NPs are promising MRI contrast agents for medical imaging.

Biomedical Applications of Liquid Metal Nanoparticles: A Critical Review.

This review is focused on the basic properties, production, functionalization, cytotoxicity, and biomedical applications of liquid metal nanoparticles (LMNPs), with a focus on particles of the size ranging from tens to hundreds of nanometers. Applications, including cancer therapy, medical imaging, and pathogen treatment are discussed. LMNPs share similar properties to other metals, such as photothermal conversion ability and a propensity to form surface oxides. Compared to many other metals, especially mercury, the cytotoxicity of gallium is low and is considered by many reports to be safe when applied in vivo. Recent advances in exploring different grafting molecules are reported herein, as surface functionalization is essential to enhance photothermal therapeutic effects of LMNPs or to facilitate drug delivery. This review also outlines properties of LMNPs that can be exploited in making medical imaging contrast agents, ion channel regulators, and anti-pathogenic agents. Finally, a foresight is offered, exemplifying underexplored knowledge and highlighting the research challenges faced by LMNP science and technology in expanding into applications potentially yielding clinical advances.

Cyclodextrin-Based Contrast Agents for Medical Imaging.

Cyclodextrins (CDs) are naturally occurring cyclic oligosaccharides consisting of multiple glucose subunits. CDs are widely used in host–guest chemistry and biochemistry due to their structural advantages, biocompatibility, and ability to form inclusion complexes. Recently, CDs have become of high interest in the field of medical imaging as a potential scaffold for the development of a large variety of the contrast agents suitable for magnetic resonance imaging, ultrasound imaging, photoacoustic imaging, positron emission tomography, single photon emission computed tomography, and computed tomography. The aim of this review is to summarize and highlight the achievements in the field of cyclodextrin-based contrast agents for medical imaging.

Impacts of anthropogenic gadolinium on the activity of the ammonia oxidizing bacterium Nitrosomonas europaea

Widespread use of gadolinium-based contrast agents in medical imaging has resulted in increased Gd inputs to municipal wastewater treatment plants. Others have reported that typical wastewater treatment does not attenuate Gd, resulting in discharges to natural waters. However, whether elevated Gd impacts the performance of biological treatment has not been investigated. We examined whether gadolinium chloride or Gd chelated with diethylenetriaminepentaacetic acid (DTPA) affected the activity of the model nitrifying bacterium Nitrosomonas europaea. At nominal GdCl3 additions ranging from 1 to 500 μM, no impact was observed compared to the control. Most (>98%) of the added Gd precipitated, and extracellular GdPO4 nanoparticles were observed. When chelated with DTPA, Gd remained soluble, but no statistically significant impact on ammonia oxidation was observed until the highest concentrations tested. At 300 and 500 μM Gd-DTPA, a temporary reduction of nitrite production relative to the control (effect size 1.3 mg l−1 and 1.5 mg l−1, respectively, at 24 h) was seen. By itself, DTPA was highly inhibitory. Modeling suggested that DTPA likely chelated other metals, but adjusting the concentrations of the most abundant metals in the medium, calcium and magnesium, indicated that lowering their free ion activities was probably not the cause of inhibition. Complexation of other essential metals was more likely. Our studies indicate that while the low bioavailability of Gd may limit its ecosystem impacts, the role of synthetic ligands used with Gd and other rare earth elements should be considered as the production, use and disposal of these elements increases.

Investigation Of Reducing Omniscan Toxicity Using Intracellular And Targeted N-Acetylcysteine Lysine Complex

Background:The main issue is finding the most efficient method in the treatment of cancer in terms of early and accurate diagnostic. One of the most modern diagnostic techniques is imaging methods. The accuracy and detection speed of MRI and CT SCAN are high.Methods:The most important complication of iodinated contrast agents in medical imaging is severe renal toxicity Nephrogenic Systemic Fibrosis (NSF). In order to reduce the cytotoxicity of kidney cells caused by the usage of iodized contrast agents a complex agent should be designed. The two drugs which have been used for the synthesis of this compound are L -lysine amino acid and NAcetyl- Cysteine (NAC).Results:The synthesis of this complex due to two dimer molecules with each other and NAC greatly a helper for an antioxidant activity and L-lysine amino acid helps in drug entry into the cells. However, helping for an antioxidant activity heavily reinforce and eventually will successfully reduce the cytotoxicity. When its exposure to HEK 293 cell line (P&lt;0.05). The reduction in toxicity at the dosage of 100 µM has been showed as the greatest reduction. The amount of renal toxicity was reported 40% in Omniscan.Conclusion:Omniscan was tested when iodinated contrast medium was combined with the synthesized 2NAC-LYS-OMNISCAN complex and the human embryonic kidney 293 (HEK293) cell line. Then, the cytotoxicity was reduced to 10 %. On the other hand, the viability increased from 60 % to 90 %, or in other words, the cytotoxicity was reduced from 40 % to 10 %.

Theranostic α-Lactalbumin-Polymer-Based Nanocomposite as a Drug Delivery Carrier for Cancer Therapy.

A nanotheranostic system was developed using α-lactalbumin along with Fe3O4 nanoparticles as an magnetic resonance imaging (MRI) contrast agent for medical imaging and doxorubicin as the therapeutic agent. α-lactalbumin was precipitated and cross-linked using poly(ethylene glycol) and glutaraldehyde. Besides, polyethylenimine was applied to increase the number of amine groups during cross-linking between α-lactalbumin and Fe3O4 nanoparticles. Interestingly, 90% of the initial protein used for the coaggregation process was incorporated in the prepared 130 nm nanocomposites, which facilitated the 85% doxorubicin loading. Formation of pH-sensitive imine bonds between glutaraldehyde and amine groups on α-lactalbumin and polyethylenimine resulted in higher release of doxorubicin at acidic pHs and consequently development of a pH-sensitive nanocarrier. The designed nanocomposite was less immunogenic owing to stimulating the production of less amounts of C3a, C5a, platelet factor 4, glycoprotein IIb/IIIa, platelet-derived β-thromboglobulin, interleukin-6, and interleukin-1β compared to the free doxorubicin. Furthermore, 1000 μg/mL nanocomposite led to 0.2% hemolytic activity, much less than the 5% standard limit. The void nanocarrier induced no significant level of cytotoxicity in breast cancer and normal cells following 96 h incubation. The doxorubicin-loaded nanocomposite presented higher cytotoxicity, apoptosis induction, and doxorubicin uptake in cancer cells than free doxorubicin. Conversely, lower cytotoxicity, apoptosis induction, and doxorubicin uptake were observed in normal cells treated with the doxorubicin-loaded nanocarrier compared to free doxorubicin. In line with the results of in vitro experiments, in vivo studies on tumor-bearing mice showed more suppression of tumor growth by the doxorubicin-loaded nanocomposite compared to the free drug. Moreover, the pharmacokinetic study revealed slow release of doxorubicin from the nanocomposite. Besides, in vitro and in vivo MRI studies presented a higher r2/r1 ratio and comparable contrast to the commercially available DOTAREM, respectively. Our findings suggest that this new nanocomposite is a promising nanotheranostic system with promising potential for cancer therapy and diagnosis.

Saxs and Spectroscopic Studies of Synthesis Procedures of Nanorods

Nanoparticles of noble metals, particularly gold nanoparticles, were a great breakthrough in nanobiotechnology, because of their unique physicochemical properties which depend on their shape and size. They can be used in modern biomedicine for example in drug delivery, as contrast agents for medical imaging or as vectors for gene therapy. Using different ways of synthesis, including also addition of surfactants at the stage of synthesis, one can get numerous types of nanoparticles of various morphology, like nanotriangles, nanoribbons or nanorods. In this study we focussed on the synthesis procedures of rod-shaped gold nanoparticles prepared using the seed-mediated growth method with various surfactants to obtain different size and prevent aggregation of gold nanorods. Surfactant molecules are amphiphilic, which means that they have hydrophobic and hydrophilic groups, and can form different microstructures in solution and therefore can mediate the synthesis of nanoparticles. As a results of the use of surfactants, different morphologies of nanoparticles can be promoted. Characterization of gold nanoparticles obtained was performed by small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Additionally, they were analysed by UV-Vis spectroscopy and nuclear magnetic resonance (NMR) diffusometry measurements to get information about their size, shape and structure. As a result, we have gained an insight on the influence of the structure of used surfactants on the morphology of obtained gold nanostructures. This research project was supported by programme Best of the Best (Najlepsi z Najlepszych) 3.0 from Ministry of Science and Higher Education (Poland).

Functionalizable composite nanoparticles as a dual magnetic resonance imaging/computed tomography contrast agent for medical imaging

ABSTRACTA dual contrast agent for computed tomography (CT) and magnetic resonance imaging (MRI) was synthesized via microemulsion polymerization. This contrast agent consists of Fe3O4 particles (d = 7 nm) with an iodine‐carrying nanopolymeric shell, with overall particle sizes ranging from 50 to 250 nm. 2‐Methacryloyloxyethyl(2,3,5‐triiodobenzoate) was used as the monomer. Sodium oleate was used as the surfactant and its amount was varied to control the overall particle size. The composite nanoparticles were mainly characterized via dynamic light scattering, with further analyses using transmission electron microscopy and atomic force microscopy. The particles provided a highly visible contrast in CT and MR images. A template for biomedical applications was created by adding a comonomer and the particles were further functionalized with the somatostatin analogue Tyr3‐octreotate. The particles were tested for specific uptake into somatostatin receptor‐positive AR42J cells. The additional uptake of the functionalized particles was investigated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47571.

Magnetic nanoparticles to improve the contrast of Magnetic Resonance Imaging

Earlier detection of diseases reduces the mortality rate. So the development of better screening techniques could be considered as a main topic of interest. In non-invasive medical imaging, specifically in Magnetic Resonance Imaging (MRI), conventional contrast agents do not have a good performance in imaging of some fine parts. The prosperity of preclinical researches in oncology that purpose at developing and evaluating curative strategies on samples, requires effective new functionalized contrast agents for portrayal tumor growth, monitoring the trace of a treatment and/or inducing the demolition of cancerous tumors. This study was performed by searching Nanotechnology, Molecular imaging, magnetic nanoparticles, and contrast agent nanoparticles keywords in Google scholar, Science direct, PubMed and Scopus websites in terms of content. We reviewed the recent studies about development of nanoparticles as contrast agents for medical imaging because they have a longer vascular half-life than molecular contrast agents. It could be indicate that nanoparticles are important items in increasing the contrast of the images so that even reducing the size of the magnetic nanoparticles escalates the contrast and half-life of the particles. Particles with a diameter of 10 nm have a greater half-life than particles with a diameter of 30 nm or larger. It was also found that to removing material defects or improve their biocompatibility; particles should be covered with other materials or doped with metals.