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Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging
Published on: December 4, 2016
A novel class of polymeric pH-responsive MRI CEST agents.
Shanrong Zhang1, Kejin Zhou, Gang Huang
1Department of Pharmacology, Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
Chemical Communications (Cambridge, England)
|June 12, 2013
Summary
Tertiary amine-based block copolymers act as pH-responsive contrast agents for magnetic resonance imaging (MRI). These polymers switch their chemical exchange saturation transfer (CEST) signal from "off" to "on" in acidic conditions, enabling pH-based imaging.
Area of Science:
- Polymer Chemistry
- Biomedical Imaging
- Nanotechnology
Background:
- Magnetic resonance imaging (MRI) is a crucial diagnostic tool.
- Developing responsive contrast agents enhances MRI sensitivity and specificity.
- pH variations are significant in various physiological and pathological processes.
Purpose of the Study:
- To investigate the potential of ionizable, tertiary amine-based block copolymers as pH-responsive contrast agents for MRI.
- To explore the chemical exchange saturation transfer (CEST) mechanism for pH sensing using these polymers.
- To demonstrate the pH-dependent switching behavior of the polymer-based contrast agents.
Main Methods:
- Synthesis of ionizable, tertiary amine-based block copolymers.
- Characterization of polymer self-assembly into micelles at physiological pH.
- Evaluation of pH-dependent changes in chemical exchange saturation transfer (CEST) signals.
- Assessment of micelle dissociation in acidic environments.
Main Results:
- Ionizable, tertiary amine-based block copolymers exhibit pH-responsive behavior.
- The CEST signal is effectively 'off' at physiological pH due to micelle formation.
- Micelle dissociation in acidic environments leads to a significant 'on' state for the CEST signal.
- This switching behavior allows for pH-based contrast enhancement in MRI.
Conclusions:
- Tertiary amine-based block copolymers can serve as effective pH-responsive contrast agents for MRI.
- The pH-dependent CEST signal switching provides a mechanism for visualizing acidic environments.
- These polymers offer a promising platform for developing advanced MRI contrast agents for various diagnostic applications.
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