Biocomposite Reinforced with Soft Coral Collagen Fibers: Towards Bio-inspired Cardiovascular Tissue Therapies

Monday April 7th 2025 at 14:00 

Wolfson Building of Mechanical Engineering, Room 206 

Abstract:

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, with coronary artery disease (CAD) and aortic stenosis (AS) being among the most prevalent conditions requiring surgical intervention. While synthetic grafts are effective for large blood vessels, they often fail in small-diameter applications. Similarly, current mechanical and bioprosthetic aortic valves have inherent limitations, such as the need for lifelong anticoagulation therapy and the risk of structural deterioration, respectively, highlighting the need for advanced biomaterials that mimic the mechanical properties and microstructure of the native tissues.

This research aims to develop novel biocomposites reinforced with ultra-long collagen fibers extracted from soft coral for use in small-diameter blood vessels (SDBVs) and aortic valve (AV) replacements. Experimental and computational studies were conducted to evaluate their mechanical behavior. Multi-scale micromechanical tissue models were developed and calibrated for both native and coral-collagen-based media. Finite element (FE) models were developed to predict the mechanical response of biocomposite constructs, demonstrating good agreement with experimental data. The proposed AV prosthetic leaflet designs are bioinspired by native microstructure. These and the entire AV were modeled using a structural parametric FE model. The results showed improved stress distribution and reduced mechanical fatigue risk.

Fluid-structure interaction (FSI) simulations provided additional hemodynamic insights into the biomechanical performance of the biocomposite AV, revealing comparable systolic flow behavior to native valves. However, differences in closure dynamics, compared to native AV, suggest that optimizing fiber volume fraction and matrix stiffness could enhance valve function. This research pioneers coupling experimental and computational approaches to advance biocomposite cardiovascular implants, offering significant promise for addressing the complex challenges associated with AV and SDBV replacements.

Bio:

Shir is a Ph.D. candidate at the School of Mechanical Engineering, Tel Aviv University, under the supervision of Prof. Rami Haj-Ali. Her research focuses on computational biomechanics and experimental mechanics of biocomposites, aiming to design and develop novel biocomposite materials reinforced with soft coral collagen fibers, inspired by the native cardiovascular tissues. Her M.Sc. research, also conducted in Prof. Haj-Ali's lab, focused on developing a novel biocomposite material for engineered small-diameter blood vessel grafts. Shir has been awarded a fellowship from the Ministry of Science to support her Ph.D. studies. She holds a B.Sc. in Biomedical Engineering and an M.Sc. in Mechanical Engineering, both from Tel Aviv University.