Removing fresh tissue from explanted polyurethane prostheses: which approach facilitates physico-chemical analysis?

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Analysis of explanted vascular prostheses is hindered by residual host tissue.
• Incomplete tissue removal compromises polymer characterization.
• Need for effective, non-damaging cleaning methods for biomaterials.

Purpose of the Study:

• To develop and validate an enzyme-based cleaning protocol for explanted polyurethane vascular prostheses.
• To assess the effectiveness of different enzyme treatments in removing host tissue.
• To enable detailed analysis of in vivo polymer degradation and structural changes.

Main Methods:

• Explanted canine polyurethane arterial prostheses (1 and 12 months) were treated with collagenase, pancreatin, and trypsin.
• A sequential collagenase-pancreatin treatment followed by Triton X-100 washing was optimized.
• Morphological (light and scanning electron microscopy) and physico-chemical (spectroscopy, DSC) analyses were performed.

Main Results:

• The sequential collagenase-pancreatin digestion effectively removed all fresh host tissue with minimal polymer damage.
• Cleaned prostheses allowed clear visualization of microporous structures and biodegraded microfibers.
• Surface and bulk properties of the polyurethane were successfully characterized post-cleaning.

Conclusions:

• A two-step enzymatic cleaning protocol (collagenase then pancreatin) is highly effective for preparing explanted polyurethane vascular prostheses.
• This method facilitates accurate monitoring of in vivo changes in polyurethane surface chemistry and bulk structure.
• The optimized technique is crucial for understanding long-term biomaterial performance and degradation.