PH‐Sensitive Polymethacrylates as Potential Contrast Agents in 19F MRI. Issue 14 (22nd April 2022)

• Record Type: Journal Article
• Authors: Zalewski, Mariusz; Janasik, Dawid; Kapała, Anna; Minoshima, Masafumi; Sugihara, Fuminori; Raj, Wojciech; Pietrasik, Joanna; Kikuchi, Kazuya; Krawczyk, Tomasz
• Is Part Of: Macromolecular chemistry and physics. Volume 223:Issue 14(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-22
• Subjects: ATRP -- contrast agents, 19F MRI -- polymethacrylates; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.202200027
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract: 19 F MRI is a promising method of diagnosis that can complement the commonly used 1 H MRI with gadolinium contrast agents. Copolymers containing fluoroorganic groups demonstrate many advantages as potential 19 F MRI contrast agents. In this work, a series of copolymers based on 2, 2, 2‐trifluoroethyl methacrylate (TFEMA), 1, 1, 1, 3, 3, 3‐hexafluoroisopropyl methacrylate (HFiPMA), 2‐(dimethylamino)ethyl methacrylate (DMAEMA), or 2‐hydroxyethyl methacrylate (HEMA) units are prepared using atom transfer radical polymerization. The highest S/N values in a 19 F NMR spectra is achieved with a copolymer containing 15–25 wt% TFEMA or 18–22 wt% HFiPMA. Copolymers of HFiPMA show a strong effect of pH on T 1 and T 2 relaxation times while only T 2 is significantly affected for the TFEMA copolymers. DFT calculations reveal that the phenomenon is most likely caused by the pH‐induced changes in the distance of fluoroorganic groups within a polymer chain. Abstract : It is demonstrated that 2, 2, 2‐trifluoroethyl methacrylate, 2‐hydroxyethyl methacrylate, 2‐(dimethylamino)ethyl methacrylate, and 1, 1, 1, 3, 3, 3‐hexafluoroisopropyl methacrylate (HFiPMA) based copolymers show strong pH‐dependent 19 F NMR relaxation and aqueous solubility. The strongest pH–property relationship in the pH 4–9 range is observed in the case of HFiPMA copolymers. This provides a potential for 19 F MR pH gradient imaging. The conformational changes due to protonation/deprotonation explain the observed behavior.