Nanodiamond-Gadolinium(III) Aggregates for Tracking Cancer Growth In Vivo at High Field.

The ability to track labeled cancer cells in vivo would allow researchers to study their distribution, growth, and metastatic potential within the intact organism. Magnetic resonance (MR) imaging is invaluable for tracking cancer cells in vivo as it benefits from high spatial resolution and the absence of ionizing radiation. However, many MR contrast agents (CAs) required to label cells either do not significantly accumulate in cells or are not biologically compatible for translational studies.

Cell labeling via membrane-anchored lipophilic MR contrast agents.

Cell tracking in vivo with MR imaging requires the development of contrast agents with increased sensitivity that effectively label and are retained by cells. Most clinically approved Gd(III)-based contrast agents require high incubation concentrations and prolonged incubation times for cellular internalization. Strategies to increase contrast agent permeability have included conjugating Gd(III) complexes to cell penetrating peptides, nanoparticles, and small molecules which have greatly improved cell labeling but have not resulted in improved cellular retention.

pH-Responsive Theranostic Polymer-Caged Nanobins (PCNs): Enhanced Cytotoxicity and MRI Contrast by Her2-Targeting.

comprises a doxorubicin (DXR)-loaded liposomal core and an acid-sensitive polymer shell that is functionalized with Herceptin and Gd-based MRI contrast agents. In vitro testing reveals a 14-fold increase in DXR-based cytotoxicity versus a non-targeted analogue and an 120-fold improvement in cellular Gd-uptake in comparison with clinically approved DOTA-Gd, leading to significant MRI contrast enhancement.

Mechanisms of Gadographene-Mediated Proton Spin Relaxation.

Gd(III) associated with carbon nanomaterials relaxes water proton spins at an effectiveness that approaches or exceeds the theoretical limit for a single bound water molecule. These Gd(III)-labeled materials represent a potential breakthrough in sensitivity for Gd(III)-based contrast agents used for magnetic resonance imaging (MRI). However, their mechanism of action remains unclear.

Reporter protein-targeted probes for magnetic resonance imaging.

Contrast agents for magnetic resonance imaging are frequently employed as experimental and clinical probes. Drawbacks include low signal sensitivity, fast clearance, and nonspecificity that limit efficacy in experimental imaging. In order to create a bioresponsive MR contrast agent, a series of four Gd(III) complexes targeted to the HaloTag reporter were designed and synthesized.

A modular system for the synthesis of multiplexed magnetic resonance probes.

We have developed a modular architecture for preparing high-relaxivity multiplexed probes utilizing click chemistry. Our system incorporates azide bearing Gd(III) chelates and a trialkyne scaffold with a functional group for subsequent modification. In optimizing the relaxivity of this new complex, we undertook a study of the linker length between a chelate and the scaffold to determine its effect on relaxivity.

Novel aerobic oxidation of primary sulfones to carboxylic acids.

Primary alkyl aryl sulfones are converted to the corresponding carboxylic acids in fair to excellent yield through double deprotonation and exposure to atmospheric oxygen. The methodology allows for the convenient synthesis of (13)C labeled carboxylic acids.

Modular polymer-caged nanobins as a theranostic platform with enhanced magnetic resonance relaxivity and pH-responsive drug release.

‘Clickable’ polymer-caged nanobins enable the combination of Gd MRI contrast agents and an anticancer drug (gemcitabine, GMC) into a single theranostic platform. The resulting Gd-conjugated, GMC-loaded PCNs (Gd-PCN) exhibit significant enhancements in relaxivity, drug uptake, and pH-sensitive drug release.

Gd(III)-nanodiamond conjugates for MRI contrast enhancement.

A Gd(III)-nanodiamond conjugate [Gd(III)-ND] was prepared and characterized, enabling detection of nanodiamonds by MR imaging. The Gd(III)-ND particles significantly reduced the T(1) of water protons with a per-Gd(III) relaxivity of 58.82 +/- 1.