Dysprosium-Modified Gold Nanoparticles as T_2ex Contrast Agents for Magnetic Resonance Imaging

Abstract

With the development of high magnetic field strength in magnetic resonance imaging (MRI), there is a demand to develop MRI contrast agents to attain high relaxation effects. Compared to typical T 1 agents, the transverse relaxation rate of T 2based contrast agents increases with increasing magnetic field strength. However, better contrast agents are needed to improve the signal-to-noise issue. Here, a series of T 2ex contrast agents composed of an Au nanoparticle (NP) and a dysprosium complex (AuNP-DyDOTA(amide) x ) were designed. The transverse relaxivity of three molecules bearing different side arm chains were investigated. After screening by NMR signals, the transverse relaxivity of AuNP-DyDOTA(amide) 2 achieved 22.9 mM −1 s −1 at 9.4 T, which is higher than dysprosium-based small molecules. The in vivo results demonstrate that the AuNP-DyDOTA(amide) 2 is very efficient for specific accumulation in tumor regions and rapid metabolization was realized, making them promising for ultrahigh field strength imaging and clinical diagnosis in the future.

Biomacromolecule-based photo-thermal agents for tumor treatment

“…Despite the high photo-thermal effect of these PTAs, their practical clinical applications are still restricted by their weak biodegradability and long-term toxicity concerns. [22][23][24] Similarly, biocompatible organic-based PTAs have also been fabricated and used for photo-thermal tumor elimination, such as indocyanine green (ICG), croconine, porphyrin liposomes, and Prussian blue. 25 However, the photo-stability and low reproducibility of such PTAs lead to low photo-thermal conversion efficiency and tumor uptake efficiency in vivo, 26 thereby limiting their further biomedical applications.…”

Magnetocatalysis: The Interplay between the Magnetic Field and Electrocatalysis

“…As one of the most innovative and noninvasive tools, the magnetic field is widely used for controlled crystal synthesis, regulating physical properties, and promoting device performance. [1][2][3][4] Both bulk band structures and surface properties can be reshaped in the presence of a magnetic field, thus inducing phenomena such as the quantum Hall effect and topological surface states and resulting in increased carrier mobility and fast electron-hole separation. [5,6] These strategies are commonly used by chemists to design and tailor various chemical reactions.…”

Engineered Protein Photo‐Thermal Hydrogels for Outstanding In Situ Tongue Cancer Therapy

“…The average accumulations of Au 3+ in nontarget organs were similar and negligible. [ 33,34 ] This suggests the E72‐Chitosan‐Ag 3 AuS 2 hydrogel by local injection could effectively prevent the circulation of the complexed inorganic NPs in body. Meanwhile, the local temperature of mice treated with the E 72 ‐Chitosan‐Ag 3 AuS 2 hydrogel was increased to 55 °C under laser irradiation of 1 W cm −2 within 3 min, which was high enough to eliminate tumor cells (Figure 3E).…”