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Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging
Published on: December 4, 2016
Targeted biodegradable dendritic MRI contrast agent for enhanced tumor imaging
Mingzhou Ye1, Yue Qian, Jianbin Tang
1Key Laboratory of Biomass Chemical Engineering of Ministry of Education and Center for Bionanoengineering, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China.
Summary
A new biodegradable dendritic contrast agent (CA) for MRI offers enhanced tumor imaging with high safety. This novel agent, FA-PEG-G2-DTPA-Gd, shows superior contrast and reduced gadolinium retention compared to existing agents.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Radiology
Background:
- Developing safe and effective contrast agents (CAs) for magnetic resonance imaging (MRI) is crucial for accurate tumor detection.
- Dendrimer-based macromolecular CAs offer tumor targeting and enhanced imaging but often suffer from poor biodegradability and toxicity.
- Non-degradable CAs can lead to long-term retention of gadolinium (Gd) in the body, raising safety concerns.
Purpose of the Study:
- To synthesize and evaluate a novel tumor-targeting biodegradable dendritic CA (DCA) for enhanced MRI contrast and improved safety profile.
- To assess the biodegradability and in vivo Gd retention of the developed DCA.
- To compare the MRI performance of the DCA with a clinically used CA.
Main Methods:
- Synthesis of a biodegradable polyester dendrimer conjugated with Gd chelates (DTPA-Gd) and PEG chains, functionalized with folic acid (FA) for tumor targeting, resulting in FA-PEG-G2-DTPA-Gd.
- Measurement of longitudinal relaxivity (r1) of the DCA.
- In vivo MRI studies using FA-PEG-G2-DTPA-Gd in tumor-bearing models to evaluate contrast enhancement and imaging duration.
- Assessment of Gd retention in various organs and tissues post-administration.
Main Results:
- The synthesized DCA (FA-PEG-G2-DTPA-Gd) exhibited a high longitudinal relaxivity of 17.1 mM(-1)s(-1), four times higher than Magnevist.
- MRI studies demonstrated clearer tumor outlining and significantly higher, longer-lasting contrast enhancement with the DCA compared to Magnevist.
- Crucially, the biodegradable DCA showed substantially lower Gd retention in organs and tissues than non-degradable dendritic CAs.
Conclusions:
- The developed tumor-targeting biodegradable dendritic CA (FA-PEG-G2-DTPA-Gd) offers superior MRI contrast enhancement and a significantly improved safety profile due to reduced Gd retention.
- This biodegradable DCA represents a promising candidate for effective contrast-enhanced tumor MRI.
- The findings highlight the potential of biodegradable dendrimers in developing next-generation MRI contrast agents.
