Constructing and evaluating the effect of micron-scale structures on von Willebrand factor damage

Area of Science:

• Biomaterials Science
• Medical Device Engineering
• Hematology

Background:

• Mechanical circulatory support (MCS) devices can cause gastrointestinal bleeding due to von Willebrand factor (VWF) damage.
• VWF damage is often attributed to mechanical factors like shear stress.
• The role of interface factors, such as material surface properties, in VWF damage remains underexplored.

Purpose of the Study:

• To investigate the impact of material surface micron-scale structures on VWF damage under flow conditions.
• To explore the relationship between surface hydrophobicity and VWF integrity.
• To provide insights for designing safer materials for MCS devices.

Main Methods:

• Established a roller pump circulation platform to simulate blood flow.
• Fabricated composite micro-structures (microngrating and micronpost) on Si wafer surfaces using lithography and reactive ion etching.
• Characterized material surfaces and analyzed VWF antigen, VWF ristocetin cofactor activity, and high molecular weight VWF degradation.

Main Results:

• Surface micro-structures increased material hydrophobicity.
• Increased surface hydrophobicity correlated with reduced VWF damage.
• VWF antigen levels, VWF activity, and high molecular weight VWF integrity were better preserved on more hydrophobic surfaces.

Conclusions:

• Surface micro-structures on MCS device materials can mitigate VWF damage.
• Modulating surface hydrophobicity through micro-structuring is a promising strategy to minimize VWF damage.
• This approach can inform the design of next-generation MCS devices with improved hemocompatibility.