A Polypeptide-Based, Membrane-Penetrating, Target-Specific Contrast Agent for Magnetic Resonance Molecular Imaging

Abstract

Molecular imaging based on magnetic resonance imaging (MRI) requires a contrast agent with high relaxivity and specificity. Much effort has been devoted to this goal over the past decades. In this work, we continue this endeavor by synthesizing an MRI contrast agent that can penetrate the cellular membrane and bind with specific proteins. It was characterized with one- and two-dimensional NMR spectroscopy, NMR micro-imaging, and mass spectroscopy. The target specificity has been further confirmed by both molecular dynamics simulation and micro-imaging on a living biological system. It is one of the largest of peptide-based bioactivated MRI contrast agents, and its relaxivity enhancement factor is among the highest of MRI contrast agents hitherto published. We envision interesting applications and extension of this smart MRI contrast agent with bio-specificity and high contrast for molecular imaging.

A dual-targeted Gd-based contrast agent for magnetic resonance imaging in tumor diagnosis

“…One work synthesized a membrane-penetrating, target-specific CA, in which RGD was used to target integrin α v β 3 on tumor cell surface and peptide of R9 was used to introduce the CA into the cells. 23 Another work reported a tumor dual-targeted MRI nano-probe with an IELLQAR peptide to conjugate tumor endothelium and a KQEFLIN peptide to enhance the internalization into cancer cells. 24 Obviously, these studies have achieved increased enrichment of CAs in tumor tissues and enhanced the signal intensity of the tumor sites.…”

Apoptosis/Necroptosis Inducing Thiazole-Containing Artificial Polypeptide for Immunogenic Cell Death of Cancer

“…Our lysine-based artificial CPP has an α-helical structure and is positively charged. These properties increase the hydrophilicity and stability of the entire CPP structure and help cellular internalization and serum stability. − …”