Geometry-Encoded Microtrenches Stabilize Endothelium on High Shear Biomaterial Surfaces

Area of Science:

• Biomaterials Science
• Cardiovascular Engineering
• Cellular Biomechanics

Background:

• Maintaining endothelial cell (EC) coverage on cardiovascular biomaterials is crucial for hemocompatibility.
• High shear stress in prosthetic devices causes ECs to detach, leading to device failure.

Purpose of the Study:

• To investigate if mesoscale surface geometry can reorganize hemodynamics and preserve EC coverage under extreme shear stress.
• To evaluate the impact of engineered microtrenches on EC retention and function.

Main Methods:

• Engineered microtrenches with varying angles (0°, 22.5°, 45°) were introduced onto biomaterial surfaces.
• Endothelial cell monolayers were exposed to supraphysiological shear stress (up to ~250 dyn/cm²).
• EC coverage, junctional protein expression (VE-cadherin), cytoskeletal and nuclear alignment, and nitric oxide production were analyzed.

Main Results:

• Microtrenched geometries attenuated shear stress and vorticity gradients, significantly improving EC retention compared to flat surfaces.
• Endothelial shear resistance increased with trench angle, with 45° trenches showing the highest protection (EC₅₀ of 207 dyn/cm²).
• Mechanoadapted ECs showed increased eNOS expression and nitrite production, while unfavorable flow conditions induced inflammatory markers (VCAM-1, PAI-1).

Conclusions:

• Geometry-driven modulation of near-wall flow is a predictive, material-agnostic strategy for endothelialization.
• Optimizing shear-vorticity coupling within specific mechanical ranges enhances endothelial persistence and vasoprotection.
• This approach offers a promising solution for improving the hemocompatibility of high-shear cardiovascular implants.