Bio-composites reinforced with unique coral collagen fibers: Towards biomimetic-based small diameter vascular grafts. (July 2021)

• Record Type: Journal Article
• Authors: Wertheimer, Shir; Sharabi, Mirit; Shelah, Ortal; Lesman, Ayelet; Haj-Ali, Rami
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 119(2021)
• Publication Date: 2021-07
• Subjects: Collagen -- Biomimetics -- Small-diameter vascular grafts -- Mechanical compatibility -- In vitro biocompatibility -- Biocomposite; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2021.104526
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: Cardiovascular Diseases (CVDs) are the leading cause of death worldwide. Approximately 31% of all global deaths are caused by CVDs, of which 42% are attributable to coronary artery disease (CAD). CAD is characterized by a narrowing of arteries that restricts the normal blood flow. Over time, surgical intervention is required in severe cases of occlusions and includes implantation of autologous vessels. Today synthetic grafts are used successfully as replacements for blood vessels with a diameter larger than 6 mm. However, they often fail as small-diameter blood vessel replacements. This study introduces a new biocomposite material system consisting of unique and long (cm-scale) collagen fibers derived from soft corals embedded within an alginate hydrogel matrix. The new biocomposite layers were used to fabricate grafts, towards developing a new class of tissue-engineered small-diameter blood vessels. These constructs consisted of both circumferentially and longitudinally oriented collagen fibers. The mechanical properties of the grafts were investigated via a new experimental setup constructed in our lab for this purpose, which applied internal pressure levels of 0–300 mmHg. Similar to native coronary arteries, the biocomposite tubes demonstrated a compliance of 4.88 ± 0.99%/100 mmHg for a physiologic pressure range of 80–120 mmHg. Furthermore, a numerical finite element simulation model is proposed to generate the overall mechanical response of the construct. It is composed of axial and circumferential fibers embedded within the continuum alginate elements. Good prediction is demonstrated when compared with the measured pressure-strain response. Moreover, we examined biocompatibility and cell growth on the collagen fibers. Fibroblast cells proliferated during the experiment that lasted for 32 days and showed aligned configuration with the collagen fiber orientation. The novelty of this study is manifested in the use of naturally derived coral-based long collagen fibers for the development of a new class of tissue-engineered grafts. The proposed novel biocomposite graft demonstrated both mechanical and biological compatibility and can be further developed for small-diameter blood-vessel replacement. Graphical abstract: Image 1 Highlights: Coral collagen fibers are used to reinforce a cylindrical biocomposite. The proposed graft exhibited a similar compliance to that of human coronary arteries. Finite element model predicted pressure-strain behavior close to the measured responses. The collagen fibers demonstrated good biocompatibility in vitro . Cell alignment was dictated by the fiber orientation.