Cardiovascular Diseases (CVDs) are the leading cause of death worldwide. Two common CVDs, aortic stenosis (AS) and coronary artery disease (CAD), restrict the normal blood flow through the valve and the arteries. In severe cases of CAD, surgical interventions are conducted to implant autologous vessels. Synthetic grafts often fail in the case of small-diameter (<6mm) blood vessels (SDBV). The treatment in severe AS cases includes an AV prosthesis, either mechanical heart valve or a bioprosthetic valve, each with its benefits and drawbacks. Therefore, there is a critical need for engineered SDBV and an optimized prosthetic AV that will mimic the mechanical properties and the microstructure of the native tissues.

This study introduces a new class of biocomposite material system consisting of unique and ultra long (cm-scale) continuous collagen fibers derived from soft corals embedded within an alginate hydrogel matrix, for cardiovascular applications. Tubular constructs consisting of both circumferentially and longitudinally oriented collagen fibers were fabricated and mechanically tested with a new internal pressure testing setup. The biocomposite tubes demonstrated compliance of 4.88±0.99 %/100 mmHg for a physiologic pressure range of 80-120 mmHg, similar to native coronary arteries. In addition, a numerical finite element (FE) simulation model is proposed to simulate the hyperelastic mechanical response of the biocomposite construct. A good prediction is demonstrated when compared with the measured pressure-strain response [1]. Furthermore, a parametric model of the AV was used in a biomimetic design of a biohybrid construct for AV cusps by tailoring the mechanical response according to the native tissue.

In-vitro biocompatibility tests and cell growth on the collagen fibers were also conducted using fibroblast cells. The experiment lasted for 32 days and showed aligned cell configurations with the orientations of the collagen fibers [2]. The proposed novel biocomposite graft demonstrated both mechanical and biological compatibility and can be the basis for future SDBV grafts and AV prostheses.