Mechanical property characterization of electrospun recombinant human tropoelastin for vascular graft biomaterials

Abstract

The development of vascular grafts has focused on finding a biomaterial that is non-thrombogenic, minimizes intimal hyperplasia, matches the mechanical properties of native vessels and allows for regeneration of arterial tissue. In this study, the structural and mechanical properties and the vascular cell compatibility of electrospun recombinant human tropoelastin (rTE) were evaluated as a potential vascular graft support matrix. Disuccinimidyl suberate (DSS) was used to cross-link electrospun rTE fibers to produce a polymeric recombinant tropoelastin (prTE) matrix that is stable in aqueous environments. Tubular 1 cm diameter prTE samples were constructed for uniaxial tensile testing and 4 mm small-diameter prTE tubular scaffolds were produced for burst pressure and cell compatibility evaluations from 15 wt% rTE solutions. Uniaxial tensile tests demonstrated an average ultimate tensile strength (UTS) of 0.36±0.05 MPa and elastic moduli of 0.15±0.04 MPa and 0.91±0.16 MPa, which were comparable to extracted native elastin. Burst pressures of 485 ± 25 mmHg were obtained from 4 mm ID scaffolds with 453 ± 74 μm average wall thickness. prTE supported endothelial cell growth with typical endothelial cell cobblestone morphology after 48 hours in culture. Cross-linked electrospun recombinant human tropoelastin has promising properties for utilization as a vascular graft biomaterial with customizable dimensions, a compliant matrix, and vascular cell compatibility.

Electrospun gelatin/PCL and collagen/PLCL scaffolds for vascular tissue engineering

“…34 With regard to selection of materials, pure gelatin or collagen has been shown to be unsuitable for vascular tissue regeneration based on factors related to structural integrity. 12,17 Previous reports indicate that degradation of PCL is slower than that of PLCL. 35,36 Our results showed abundant nondegraded scaffolds in the gelatin/PCL group 6 weeks post implantation in addition to the presence of heterogeneous structures and relatively less collagen fiber formation.…”

“…However, scaffolds prepared from natural components alone fail to achieve the desired mechanical characteristics, being unable to retain their structural integrity and swelling in aqueous environments. 12,17 On the other hand, synthetic electrospun scaffolds containing materials such as polycaprolactone (PCL), poly(L-lactide-co-ε-caprolactone) (PLCL), and poly(L-lactide-co-glycolide) have been shown to have good mechanical strength and tunable biodegradability. 13,18,19 Interestingly, more promising results have been achieved by combining natural and synthetic polymers.…”

Manufacturing of Biodegradable Scaffolds to Engineer Artificial Blood Vessel

“…Xenografts suffer from their relatively shorter life span (18). Synthetic prosthetic grafts become rejected by the immune system of the body if the diameter of the vessel is smaller than 6 mm (reocclusion, thrombosis and aneurysm) due to mismatch of compliance (17,18,19,20). So far it has been shown that tissue engineering could be an alternative approach for creating new vascular grafts.…”

“…The use of autografts and allografts is limited due to the lack of tissue donors, previous harvesting or anatomical variability (17). Xenografts suffer from their relatively shorter life span (18). Synthetic prosthetic grafts become rejected by the immune system of the body if the diameter of the vessel is smaller than 6 mm (reocclusion, thrombosis and aneurysm) due to mismatch of compliance (17,18,19,20).…”

A review of electrospinning manipulation techniques to direct fiber deposition and maximize pore size

“…The scaffolds are porous and have fibers that can be tailored to affect cell differentiation, proliferation, and migration [34][35][36][37][38]. These characteristics make electrospun constructs ideal for wound dressings [39,40] and grafts for various tissues such as skin [32,[41][42][43][44][45][46], nerves [32,33,[47][48][49][50][51], vasculature [32,33,41,[51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66], muscle [33,51,67,68], bone [15,32,33,41,51,[69]…”