Gd-based Macromolecules and Nanoparticles as Magnetic Resonance Contrast Agents for Molecular Imaging

Abstract

As we move towards an era of personalized medicine, molecular imaging contrast agents are likely to see an increasing presence in routine clinical practice. Magnetic resonance (MR) imaging has garnered particular interest as a platform for molecular imaging applications due its ability to monitor anatomical changes concomitant with physiologic and molecular changes. One promising new direction in the development of MR contrast agents involves the labeling and/or loading of nanoparticles with gadolinium (Gd). These nanoplatforms are capable of carrying large payloads of Gd, thus providing the requisite sensitivity to detect molecular signatures within disease pathologies. In this review, we discuss some of the progress that has recently been made in the development of Gd-based macromolecules and nanoparticles and outline some of the physical and chemical properties that will be important to incorporate into the next generation of contrast agents, including high Gd chelate stability, high “relaxivity per particle” and “relaxivity density”, and biodegradability.

Effects of PEGylation on the physicochemical properties and in vivo distribution of organic nanotubes

“…27,35,36 In this study, 10 mol% of DOTA-lipid 3 was coassembled with 1 and 2 and the ONTs were labeled with gadolinium(III) acetate (0.9 equivalent to 3) for the in vivo quantitative detection of ONTs by ICP-AES. Since dialysis treatment has removed any free 3, gadolinium ions should specifically complex with the ONTs on the inner surface.…”

Two Binuclear Nonionic Magnetic Resonance Contrast Agents with High Relaxivity

“…NMR spectra were recorded on a Varian Inova 300 spectrometer and a 500 MHz Bruker Ascend Avance III HD at room temperature. Chemical shifts for 1 H NMR and 13 C NMR were reported as δ, and referenced to an internal deuterated solvent central line. Multiplicity and coupling constants (J) were calculated automatically on MestReNova 10.0, a NMR processing software from Mestrelab Research.…”

“…For this purpose, one method is to connect small molecule weight CAs with macromolecules such as proteins, dendrimers, nanoparticles, or liposomes. [12,13] However, the macromolecules usually have relatively slow clearance rates in human body, which is disadvantageous to the practical application. [14,15] Construction of multiple-nuclear agents by fusing several small-molecule agents together is another approach to elongate the rotational correlation time.…”

“…H NMR and 13 C NMR spectra, mass spectra of the synthesized compounds. The Supporting Information is available free of charge via the Internet at http://sioc-journal.cn/.…”

An “imaging-biopsy” strategy for colorectal tumor reconfirmation by multipurpose paramagnetic quantum dots

“…Clinical MRI contrast agents (CAs) include Gd (III) chelates, e.g., Gd-DTPA-BMA, Gd-DOTA, and other small molecular Gd-based CAs. Their structures are stable, but with poor relaxivity, specificity, and retention time in blood stream [12,13]. A promising solution to improving MRI sensitivity and specificity can be achieved by conjugation specific CAs with anti-tumor biomarker antibodies.…”