MRI-visible poly(ε-caprolactone) with controlled contrast agent ratios for enhanced visualization in temporary...

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Medical Imaging

Background:

• Hydrophobic macromolecular contrast agents (MMCAs) are crucial for enhancing magnetic resonance (MR) imaging of implantable medical devices.
• Developing safe and effective MMCAs is essential for improving diagnostic capabilities and patient outcomes.

Purpose of the Study:

• To synthesize and evaluate novel biodegradable poly(ε-caprolactone)-based MMCAs.
• To assess the influence of gadolinium (Gd(3+)) grafting density on MR visibility and agent properties.
• To determine the stability and cytocompatibility of these novel agents for biomedical applications.

Main Methods:

• Synthesis of poly(α-propargyl-ε-caprolactone-co-ε-caprolactone) via ring-opening copolymerization.
• Preparation of a diazido derivative of a diethylenetriaminepentaacetic acid (DTPA)/Gd(3+) complex.
• Cu(I)-catalyzed [3 + 2] cycloaddition (click ligation) to couple the Gd(3+) complex onto the polymer backbone.
• Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for elemental analysis.
• Evaluation of T1 relaxation times and MRI visibility.
• Assessment of agent stability and cytocompatibility.

Main Results:

• Successfully synthesized biodegradable poly(ε-caprolactone)-based MMCAs with varying Gd(3+) content (1.0, 2.6, and 3.6 wt%).
• Demonstrated efficient click ligation for conjugating the Gd(3+) complex to the polymer.
• Observed a correlation between Gd(3+) grafting density and T1 relaxation times, impacting MRI visibility.
• Confirmed good stability and cytocompatibility of the developed MMCAs.

Conclusions:

• Novel biodegradable MMCAs based on poly(ε-caprolactone) were successfully synthesized and characterized.
• The developed MMCAs show promising potential as MRI-visible biomaterials for medical devices.
• These agents offer a safe and efficient approach to enhance MR imaging contrast for biomedical applications.