Recent advancements in the bioprinting of vascular grafts

Abstract

Recent advancements in the bioinks and three-dimensional (3D) bioprinting methods used to fabricate vascular constructs are summarized herein. Critical biomechanical properties required to fabricate an ideal vascular graft are highlighted, as well as various testing methods have been outlined to evaluate the bio-fabricated grafts as per the Food and Drug Administration (FDA) and International Organization for Standardization (ISO) guidelines. Occlusive artery disease and cardiovascular disease are the major causes of death globally. These diseases are caused by the blockage in the arteries, which results in a decreased blood flow to the tissues of major organs in the body, such as the heart. Bypass surgery is often performed using a vascular graft to re-route the blood flow. Autologous grafts represent a gold standard for such bypass surgeries; however, these grafts may be unavailable due to the previous harvesting or possess a poor quality. Synthetic grafts serve well for medium to large-sized vessels, but they fail when used to replace small-diameter vessels, generally smaller than 6 mm. Various tissue engineering approaches have been used to address the urgent need for vascular graft that can withstand hemodynamic blood pressure and has the ability to grow and remodel. Among these approaches, 3D bioprinting offers an attractive solution to construct patient-specific vessel grafts with layered biomimetic structures.

Tyramine-Functionalized Alginate-Collagen Hybrid Hydrogel Inks for 3D-Bioprinting

“…Such hydrogel inks consist of either synthetic or natural polymers with versatile chemical moieties to form a water-swollen crosslinked network. Bioinks from natural biomaterials are frequently preferred over synthetic ones because of their inherent biomimetic extracellular matrix (ECM) structures [ 5 , 6 , 7 ]. ECM-mimicking approaches incorporate specific ratios and physical spacings of glycosaminoglycans and fibrous proteins (e.g., elastin/collagen) that constitute the native ECM of cardiovascular tissues [ 8 ].…”

Melt Electrowriting of a Photo‐Crosslinkable Poly(ε‐caprolactone)‐Based Material into Tubular Constructs with Predefined Architecture and Tunable Mechanical Properties

“…The only significant difference between noncrosslinked and crosslinked samples is present in the 80:20 blend group (Figure 4C) ( p < 0.0001). When comparing Young's moduli with values from literature, the blended samples all range in the relevant window of 2–4 MPa which corresponds to average values from human saphenous vein (1.77 ± 1.2 MPa), radial artery (3.68 ± 2.05 MPa) and coronary artery, which are in the range from 1.5 [ 51,52 ] to 4 MPa, [ 53 ] depending on the specimen and test protocol used. With that, the blending allowed the manufactured constructs to be closer to human blood vessels regarding their young's modulus, whereas constructs made only from PCL do not reach these ranges.…”

Tri-Layered Vascular Grafts Guide Vascular Cells’ Native-like Arrangement

“…Artificial vascular grafts with enough mechanical strength can resist blood pressure continuously [ 28 , 29 , 30 , 31 ]. In the radial direction, the maximum stress, breaking strain, and modulus of TVGs were comparable to WSGs, while largely higher than those of ESGs, mainly due to the existence of circumferentially aligned fibers ( Figure 3 a–d).…”