Scientists have recently developed a nanoprobe that uses ultra-tiny NaGdF4 nanoparticles coated with a red blood cell membrane. The nanoprobe showed improved longitudinal molar relaxivity compared to gadolinium used in gadolinium diethylenetriaminopentaacetic acid. This study is available as a pre-test at ACS Applied Materials and Interfaces.
Study: Ultra small NaGdF4 nanoprobes coated with red blood cell membrane for high resolution 3D magnetic resonance angiography. Image credit: Kateryna Kon / Shutterstock.com
Magnetic resonance angiography (MRI).
Magnetic resonance imaging (MRI) studies non-invasive hemodynamics and vascular anatomy.
The technique has evolved from a contrast-free blood flow imaging technique to dynamic contrast three-dimensional (3D DCE) MRI angiography with higher spatio-temporal resolution.
Although digital subtraction angiography is considered the gold standard for detecting vascular disease, it has several limitations. In contrast, MRI angiography provides a similar result, but also minimizes the risks associated with iodinated contrast agents, arterial catheterization, and radiation risks.
Paramagnetic contrast agents play an important role in the development of high quality MRI angiography with fast 3D gradient echo sequences. Without contrast agents, these sequences would not generate a prominent vascular contrast due to the short repetition times.
In clinical settings, polyamino polycarboxylic chelates of gadolinium ions (Gd3 +) are popularly used as a paramagnetic contrast agent. However, this low molecular weight substance has been associated with several limitations that limit its application in clinical settings, especially in terms of its angiographic performance.
With its tiny hydrodynamic size, this contrast agent can quickly leave the blood vessels and disperse into the extracellular space. Therefore, it is important to establish a short acquisition time for MRI angiography. This time limit poses difficulties in achieving the accuracy required for 3D DCE angiography image resolution.
Paramagnetic contrast agent in MRI angiography
The performance of small molecule Gd chelating contrast agents on MRI scans has been unsatisfactory. This is due to the fact that the longitudinal molar relaxivity (r1) is not sufficient to improve the vascular signal ratio in depth, which minimizes the resolution of the image in 3D DCE angiography, in particular, while microvessels are shown.
Fast drop time (τR) also influences the generation of unsatisfactory images.
Scientists have previously used Gd-based paramagnetic nanoparticles (10 nm diameter) as a contrast agent for relaxation time (T1). Because the size of the nanoparticles was larger than the spacing of vascular endothelial cells, they could remain contained within the blood lumen and rarely diffuse into the interstitial space.
It is important to note that these nanoparticles also have a longer blood half-life.
The τR of Gd-based nanoparticles is substantially higher compared to the small molecular chelates of Gd, which helps to overcome the limitations associated with its application in high-resolution MR angiography.
Development of red blood cell membrane (RBCm) -based nanosubes – ultra-small coated NaGdF4 nanoparticles: a new study
Researchers have developed and characterized [email protected] nanoprobes.
Transmission electron microscopy (TEM) analysis revealed that [email protected] The nanoprobes were about 20 nm in diameter and were loaded with groups of PEG-coated nanoparticles (NP-PEG) within the cell membrane.
The scientists observed that NP-PEG was successfully coated with RBCm.
According to the results of dynamic light scattering (DLS), no aggregation of undesirable nanoparticles was observed. The authors evaluated the potential of [email protected] nanoprobes for clinical application and reported showing a robust T1 contrast enhancement effect. Based on cytotoxicity assays, [email protected] Nanoprobes were considered safe for use. This biosafety has been attributed to the coating of the RBC membrane, which has also improved biocompatibility.
Researchers have performed in vivo analyzes using rodent animals to study the ability of [email protected] nanosondes in MRI angiography. They used NP-PEG and GdDTPA as controls. MRI angiography images were obtained 15 minutes before and after administration [email protected] nanoprobes.
Scientists observed this [email protected] The nanoprobes penetrated the vascular branch and dispersed only into the vascular lumen without extravasation. This nanoprobe demonstrated excellent angiography performance. The vascular system of mice was visible on enhanced MR angiography with probe.
The authors further investigated the pharmacokinetics of [email protected] nanoprobes in the circulatory system. They observed that both NP-PEG and newly designed nanoprobes showed a similar trend and the contrast in the jugular vein of a mouse improved significantly after injection.
This was not the case when the mouse was injected with Gd-DTPA, i.e., after 10 minutes of administration, a slightly slight jugular vein was seen. In addition, the researchers observed that the [email protected] Nanosubes have a blood half-life that meets the requirements for real-time observation in clinical settings for thrombolytic treatment.
The researchers studied the biosecurity of the [email protected] nanoprobes and reported it [email protected] The nanoprobes did not cause any noticeable inflammation or have any adverse effect on any organ.
Conclusion
The authors presented an extraordinary MRI angiography nanoprobe, which is extremely useful for studying microvessels and vascular disorders. This nanoprobe has clearly demonstrated its potential for use in clinical applications in the future.
Font
He, F. et al. (2022) Ultra-small NaGdF4 nanosubes coated with red blood cell membrane for high-resolution 3D MRI angiography. Materials and interfaces applied ACS. https://doi.org/10.1021/acsami.2c03530
Disclaimer: The views expressed herein are those of the author expressed in private and do not necessarily represent the views of AZoM.com Limited T / A AZoNetwork the owner and operator of this website. This disclaimer is part of the Terms and Conditions of Use of this website.