Towards compliant small-diameter vascular grafts: Predictive analytical model and experiments
| Autor: | Abdellah Ajji, Marion Maire, Matthieu Gauthier, Mélusine Bouchet, Sophie Lerouge |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
medicine.medical_treatment Polyesters Polyurethanes Modulus Bioengineering 02 engineering and technology 010402 general chemistry 01 natural sciences Prosthesis Models Biological Permeability Biomaterials chemistry.chemical_compound Elastic Modulus Tensile Strength medicine Pressure Elastic modulus Tissue Scaffolds technology industry and agriculture 021001 nanoscience & nanotechnology Electrospinning 0104 chemical sciences Blood Vessel Prosthesis Compliance (physiology) chemistry Mechanics of Materials Permeability (electromagnetism) Polycaprolactone Stress Mechanical 0210 nano-technology Burst pressure Biomedical engineering |
| Zdroj: | Materials scienceengineering. C, Materials for biological applications. 100 |
| ISSN: | 1873-0191 |
| Popis: | The search for novel, more compliant vascular grafts for the replacement of blood vessels is ongoing, and predictive tools are needed to identify the most promising biomaterials. A simple analytical model was designed that enables the calculation of the ratio between the ultimate stress (σult) and the elastic modulus (E). To reach both the compliance of small-diameter coronary arteries (0.0725%/mmHg) and a burst pressure of 2031 mmHg, a material with a minimum σult/E ratio of 1.78 is required. Based on this result and on data from the literature, random electrospun Polyurethane/Polycaprolactone (PU/PCL) tubular scaffolds were fabricated and compared to commercial ePTFE prostheses. PU/PCL grafts showed mechanical properties close to those of native arteries, with a circumferential elastic modulus of 4.8 MPa and a compliance of 0.036%/mmHg at physiological pressure range (80–120 mmHg) for a 145 μm-thick prosthesis. In contrast, commercial expanded polytetrafluoroethylene (ePTFE) grafts presented a high Young's modulus (17.4 MPa) and poor compliance of 0.0034%/mmHg. The electrospun PU/PCL did not however reach the target values as its σult/E ratio was lower than expected, at 1.54, well below the calculated threshold (1.78). The model tended to overestimate both the compliance and burst pressure, with the differences between the analytical and experimental results ranging between 13 and 34%, depending on the pressure range tested. This can be explained by the anisotropy of random electrospun PU/PCL and its slightly non-linear elastic behavior, in contrast to the hypotheses of our model. Impermeability tests showed that the electrospun scaffolds were impermeable to blood for all thicknesses above 50 μm. In conclusion, this analytical model allows to select materials with suitable mechanical properties for the design of small-diameter vascular grafts. The novel electrospun PU/PCL tubular scaffolds showed strongly improved compliance as compared to commercial ePTFE prostheses. |
| Databáze: | OpenAIRE |
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