Encapsulation of contrast imaging agents by polypropyleneimine-based dendrimers

Area of Science:

• Biomaterials Science
• Nanotechnology
• Medical Imaging

Background:

• Polypropyleneimines (PPIs) are versatile dendritic polymers with potential applications in drug delivery and diagnostics.
• Gadolinium complexes are widely used as contrast agents in Magnetic Resonance Imaging (MRI) due to their paramagnetic properties.
• Enhancing the relaxivity of gadolinium-based contrast agents can improve MRI sensitivity and diagnostic capabilities.

Purpose of the Study:

• To synthesize and characterize glycerol-functionalized polypropyleneimines (PPIs).
• To evaluate the cytotoxicity of the functionalized PPIs.
• To assess the encapsulation efficiency of gadolinium complexes within the PPI dendrimers.
• To determine the relaxivity of the encapsulated gadolinium complexes for potential MRI applications.

Main Methods:

• Synthesis of glycerol-functionalized polypropyleneimines (PPIs).
• Characterization using diffusion-ordered spectroscopy NMR.
• Cytotoxicity assessment against MRC5 fibroblasts.
• Encapsulation of gadopentetate dimeglumine (GdBOPTA).
• T(1) measurements to determine relaxivity of encapsulated GdBOPTA in fourth and fifth generation dendrimers (GD-PPI-4 and GD-PPI-5).

Main Results:

• Successful preparation and characterization of glycerol-functionalized PPIs.
• Demonstrated low cytotoxicity of the dendrimers against MRC5 fibroblasts.
• Evaluated encapsulation capacities for gadolinium complexes.
• Measured a slight increase in the relaxivity of gadolinium chelate (GdBOPTA) when encapsulated within GD-PPI-4 and GD-PPI-5 compared to the free chelate.

Conclusions:

• Glycerol-functionalized PPIs are biocompatible and suitable for encapsulating gadolinium complexes.
• The PPI dendrimers show potential for enhancing MRI contrast agent relaxivity.
• These findings suggest a promising avenue for developing novel MRI contrast agents with improved performance.