Engineering Gd-loaded nanoparticles to enhance MRI sensitivity viaT₁shortening

Abstract

Magnetic resonance imaging (MRI) is a noninvasive imaging technique capable of obtaining highresolution anatomical images of the body. Major drawbacks of MRI are the low contrast agent sensitivity and inability to distinguish healthy tissue from diseased tissue, making early detection challenging. To address this technological hurdle, paramagnetic contrast agents have been developed to increase the longitudinal relaxivity (R 1 ), leading to an increased signal-to-noise ratio. This review focuses on methods and principles that enabled the design and engineering of nanoparticles to deliver contrast agents with enhanced ionic relaxivities. Different engineering strategies and nanoparticle platforms will be compared in terms of their manufacturability, biocompatibility properties, and their overall potential to make an impact in clinical MR imaging.

Enhancing T 1 magnetic resonance imaging contrast with internalized gadolinium(III) in a multilayer nanoparticle

“…According to the Solomon-BloembergenMorgan (SBM) theory of paramagnetic relaxation, the main factors that affect the relaxivity of Gd(III)-based contrast agents are molecular diffusional and rotational times, number of coordinated water molecules, water proton residency lifetime, and water exchange rate (32). In general, a decrease in the molecular diffusion and rotation times leads to an increased T 1 relaxivity, especially at low magnetic fields (13,33).…”

“…In general, a decrease in the molecular diffusion and rotation times leads to an increased T 1 relaxivity, especially at low magnetic fields (13,33). Therefore, the incorporation of Gd(III) into nanostructures decreases its molecular tumbling rate and, consequently, reduces its diffusional and rotational correlation time, increasing relaxivity (32). Besides the enhanced T 1 relaxivity, another important advantage of nanostructured systems is the increased accumulation of carriers in target tissue.…”

“…Besides the enhanced T 1 relaxivity, another important advantage of nanostructured systems is the increased accumulation of carriers in target tissue. For example, the enhanced permeability and retention effect in tumors can be exploited for passive targeting using nanoparticles (34), which increases the local concentration of the contrast agent in the tumor (32).…”

Design, synthesis, and evaluation of VEGFR-targeted macromolecular MRI contrast agent based on biotin–avidin-specific binding

“…Despite the large number and promising results of developed MRI contrast agents, the complicated preparation process still remained challenging. 10,11 Furthermore, enduing contrast agents with active targeting properties is another concern for developing the next-generation contrast agents for increasing the sensitivity and accuracy of imaging in target tissues or cells. 12 In this article, the novel T1 contrast agents, which have high gadolinium (Gd)-loading and active targeting functions with simple preparation process, were expected to be developed.…”

Magnetic resonance-guided regional gene delivery strategy using a tumor stroma-permeable nanocarrier for pancreatic cancer

“…) and Gd-DP/plasmid (0.90 mM ions were embedded by plasmid in the nanoparticles and limited the interaction with water protons 23 ( Figure 2D). …”