Pharmacokinetic Profiling of Unlabeled Magnetic Nanoparticles Using Magnetic Particle Imaging as a Novel Cold Tracer Assay.

We present a magnetic particle imaging (MPI)-based assay for calculating the blood half-life and tissue uptake of magnetic nanoparticles (MNPs) without the need of labeling them. Dual-catheterized rats received 2.0 mg Fe of Synomag-D70, Synomag-D50, ferucarbotran, and Feraheme by femoral vein injection.

Cell-Penetrating and Enzyme-Responsive Peptides for Targeted Cancer Therapy: Role of Arginine Residue Length on Cell Penetration and In Vivo Systemic Toxicity.

For the improved delivery of cancer therapeutics and imaging agents, the conjugation of cell-penetrating peptides (CPPs) increases the cellular uptake and water solubility of agents. Among the various CPPs, arginine-rich peptides have been the most widely used. Combining CPPs with enzyme-responsive peptides presents an innovative strategy to target specific intracellular enzymes in cancer cells and when combined with the appropriate click chemistry can enhance theranostic drug delivery through the formation of intracellular self-assembled nanostructures.

Tumor-tropic Trojan horses: Using mesenchymal stem cells as cellular nanotheranostics.

Various classes of nanotheranostics have been developed for enhanced tumor imaging and therapy. However, key limitations for a successful use of nanotheranostics include their targeting specificity with limited off-site tissue accumulation as well as their distribution and prolonged retention throughout the entire tumor. Due to their inherent tumor-tropic properties, the use of mesenchymal stem cells (MSCs) as a "Trojan horse" has recently been proposed to deliver nanotheranostics more effectively.