Issue 29, 2020

Pro-organic radical contrast agents (“pro-ORCAs”) for real-time MRI of pro-drug activation in biological systems

Abstract

Nitroxide-based organic-radical contrast agents (ORCAs) are promising as safe next-generation magnetic resonance imaging (MRI) tools. Nevertheless, stimuli-responsive ORCAs that enable MRI monitoring of prodrug activation have not been reported; such systems could open new avenues for prodrug validation and image-guided drug delivery. Here, we introduce a novel “pro-ORCA” concept that addresses this challenge. By covalent conjugation of nitroxides and drug molecules (doxorubicin, DOX) to the same brush-arm star polymer (BASP) through chemically identical cleavable linkers, we demonstrate that pro-ORCA and prodrug activation, i.e., ORCA and DOX release, leads to significant changes in MRI contrast that correlate with cytotoxicity. This approach is shown to be general for a range of commonly used linker cleavage mechanisms (e.g., photolysis and hydrolysis) and release rates. Pro-ORCAs could find applications as research tools or clinically viable “reporter theranostics” for in vitro and in vivo MRI-correlated prodrug activation.

Graphical abstract: Pro-organic radical contrast agents (“pro-ORCAs”) for real-time MRI of pro-drug activation in biological systems

Supplementary files

Article information

Article type
Paper
Submitted
17 Apr 2020
Accepted
22 Jun 2020
First published
26 Jun 2020
This article is Open Access
Creative Commons BY license

Polym. Chem., 2020,11, 4768-4779

Pro-organic radical contrast agents (“pro-ORCAs”) for real-time MRI of pro-drug activation in biological systems

H. V.-T. Nguyen, A. Detappe, P. Harvey, N. Gallagher, C. Mathieu, M. P. Agius, O. Zavidij, W. Wang, Y. Jiang, A. Rajca, A. Jasanoff, I. M. Ghobrial, P. P. Ghoroghchian and J. A. Johnson, Polym. Chem., 2020, 11, 4768 DOI: 10.1039/D0PY00558D

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