Modified polysaccharides as potential (19)F magnetic resonance contrast agents

Area of Science:

• Biomaterials Science
• Medical Imaging
• Polymer Chemistry

Background:

• Polysaccharides like alginic acid, dextran, and polygalacturonic acid are biocompatible but lack inherent imaging capabilities.
• Fluorine-19 Magnetic Resonance Imaging (19F MRI) offers high specificity and sensitivity for targeted imaging applications.
• Developing novel, safe, and effective fluorine-containing contrast agents is crucial for advancing 19F MRI.

Purpose of the Study:

• To synthesize novel water-soluble fluorinated polysaccharides for potential use as 19F MRI contrast agents.
• To characterize the physicochemical properties, including fluorine content and NMR signals, of the synthesized materials.
• To evaluate the biocompatibility, cellular uptake, biodistribution, and clearance profile of the modified polysaccharides.

Main Methods:

• Modification of alginic acid, dextran, and polygalacturonic acid (10-100 kDa) using 3-aminobenzotrifluoride via imine formation and reduction.
• Quantification of fluorine content (1-14%) and analysis of 19F NMR spectra (-63 to -63.5 ppm).
• Measurement of T1 and T2 relaxation times, assessment of cytotoxicity and cellular uptake in HeLa cells, and biodistribution studies in vivo following intravenous injection.

Main Results:

• Water-soluble fluorinated polysaccharides with 1-14% fluorine content were successfully synthesized.
• The materials exhibited low toxicity, similar cellular uptake to native polysaccharides, and preferential localization in lysosomes.
• Modified dextran showed rapid clearance via urine, with no significant accumulation in the liver, spleen, or kidneys.

Conclusions:

• The synthesized fluorinated polysaccharides are biocompatible, water-soluble, and possess suitable properties for 19F MRI.
• These materials demonstrate potential for imaging the gastrointestinal and genitourinary tracts.
• The modified polysaccharides serve as a foundation for developing more complex 19F MRI contrast agents.