In vivo biocompatibility and biostability of modified polyurethanes

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Segmented polyurethanes are widely used in biomedical applications.
• Assessing the in vivo biostability and biocompatibility of modified polyurethanes is crucial for their clinical translation.
• Understanding material degradation mechanisms informs the design of more durable medical implants.

Purpose of the Study:

• To evaluate and compare the biostability and biocompatibility of modified polyether polyurethanes and polycarbonate polyurethanes.
• To investigate the influence of material composition and surface properties on cellular response and biodegradation.
• To determine the long-term degradation profiles of different polyurethane formulations in vivo.

Main Methods:

• In vivo cage implant system used for time intervals up to 10 weeks.
• Characterization of materials pre- and post-implantation using techniques like ATR-FTIR and SEM.
• Assessment of cellular response via exudate analysis and quantification of macrophage and foreign body giant cell (FBGC) densities.

Main Results:

• All tested polyurethanes showed similar acute and chronic inflammatory responses.
• PDMS endcapped polyether polyurethane (SPU-S) exhibited lower FBGC densities and cell coverage due to its hydrophobic surface.
• Polycarbonate polyurethanes demonstrated significantly lower biodegradation rates compared to polyether polyurethanes, attributed to the oxidative stability of the carbonate linkage.

Conclusions:

• Polycarbonate polyurethanes offer enhanced biostability and biocompatibility compared to polyether polyurethanes.
• PDMS endcapping and carbonate linkages effectively reduce polyurethane biodegradation in vivo.
• Modified polyurethanes, particularly polycarbonate-based ones, show promise for long-term biomedical applications.