Strategy for the hemocompatibility testing of microparticles

Area of Science:

• Biomaterials Science
• Hemocompatibility Testing
• Polymer Microparticles

Background:

• Polymer microparticles are used in medical devices, requiring rigorous hemocompatibility evaluation.
• Existing in vitro assays for hemocompatibility are often non-standardized and lack dynamic whole blood analysis.
• Regulatory agencies mandate thorough in vitro testing to prevent adverse events like thrombosis and inflammation.

Purpose of the Study:

• To develop and validate a standardized in vitro dynamic whole blood test system for assessing polymer microparticle hemocompatibility.
• To evaluate the hemocompatibility of poly(ether imide) (PEI) microparticles with varying surface properties.
• To analyze microparticle interactions with whole blood, including thrombus formation, cell counts, and platelet activation.

Main Methods:

• Utilized a novel syringe-based dynamic test system with fresh human whole blood under standardized conditions.
• Incorporated sterilized poly(ether imide) (PEI) microparticles (140±30 μm) with nanoporous surfaces and varying wettabilities.
• Analyzed thrombi formation, circulating blood cell counts, platelet activation (P-Selectin), platelet function (PFA100), thrombin formation, and hemolysis (free hemoglobin).

Main Results:

• Microscopic evaluation showed thrombi formation and particle aggregation with all tested microparticles.
• Significant reductions in circulating platelets and monocytes (up to 50%) were observed compared to controls.
• Elevated platelet activation, thrombin levels, and hemolysis indicated clear differentiation between particle types and validated the test system's sensitivity.

Conclusions:

• The developed in vitro dynamic whole blood test system provides sensitive and validated hemocompatibility analysis for polymer microparticles.
• The system effectively differentiates between microparticle types based on their interactions with whole blood components.
• This test system enables comprehensive evaluation of cell-material interactions and platelet function, crucial for biomaterial development in medical devices.