Comparison of the Behavior of 3D-Printed Endothelial Cells in Different Bioinks

Abstract

Biomaterials with characteristics similar to extracellular matrix and with suitable bioprinting properties are essential for vascular tissue engineering. In search for suitable biomaterials, this study investigated the three hydrogels alginate/hyaluronic acid/gelatin (Alg/HA/Gel), pre-crosslinked alginate di-aldehyde with gelatin (ADA-GEL), and gelatin methacryloyl (GelMA) with respect to their mechanical properties and to the survival, migration, and proliferation of human umbilical vein endothelial cells (HUVECs). In addition, the behavior of HUVECs was compared with their behavior in Matrigel. For this purpose, HUVECs were mixed with the inks both as single cells and as cell spheroids and printed using extrusion-based bioprinting. Good printability with shape fidelity was determined for all inks. The rheological measurements demonstrated the gelling consistency of the inks and shear-thinning behavior. Different Young’s moduli of the hydrogels were determined. However, all measured values where within the range defined in the literature, leading to migration and sprouting, as well as reconciling migration with adhesion. Cell survival and proliferation in ADA-GEL and GelMA hydrogels were demonstrated for 14 days. In the Alg/HA/Gel bioink, cell death occurred within 7 days for single cells. Sprouting and migration of the HUVEC spheroids were observed in ADA-GEL and GelMA. Similar behavior of the spheroids was seen in Matrigel. In contrast, the spheroids in the Alg/HA/Gel ink died over the time studied. It has been shown that Alg/HA/Gel does not provide a good environment for long-term survival of HUVECs. In conclusion, ADA-GEL and GelMA are promising inks for vascular tissue engineering.

Characterization of two different alginate-based bioinks and the influence of melanoma growth within

“…Another indicator is the diagonal crossing ratio (DCR), which indicates whether printed strands either retain their ideal shape or fuse together after stacking. In accordance with a previous study, ADA-GEL shows a DCR value closer to 1 than Alg/HA/Gel, which indicates better printability of the ink 28 , 29 . This property of ADA-GEL was strongly influenced by the pre-crosslinking step which had a significant positive effect on the shape fidelity of the gel, while also shear thinning is given 17 .…”

“…Accordingly, a higher number of cells could increase the cellular influence. Comparing the storage modulus E′ measured in the rheometer with the Young’s modulus of MicroTester compression measurements of empty gels, similar ratios between Alg/HA/Gel und ADA-GEL can be observed 28 . This is true even though in the present study gels were printed and not cast.…”

“…Similar spreading has already been demonstrated in pre-crosslinked alginate with murine fibroblasts 17 . In addition, migratory behavior of sprouting of endothelial cells was also shown in printed pre-crosslinked ADA-GEL, while in Alg/HA/Gel, it was not possible for the endothelial cells to form sprouts from spheroids, similar to Mel Im in this study 28 . It has been demonstrated that the pre-crosslinking of alginate or ADA increases the stress relaxation amplitude of the hydrogel and facilitates migration, proliferation and spreading 39 .…”

“…The degradation of the gels was previously measured in terms of mass and shows comparable values for a period of 14 days. A weight reduction of 23.82% was observed for ADA-GEL and 34.87% for Alg/HA/Gel 28 . It is possible that this is related to the fact that unbound gelatin in Alg/HA/Gel diffuses out of the gel over time.…”

GelMA synthesis and sources comparison for 3D multimaterial bioprinting

“…A comparison between the two synthesis protocols was performed on GelMA derived from Type A and B gelatin with a High DoF, as it is found to be the most widely used in literature for bioprinting applications due to its ability to maintain good printability and promotion of cell proliferation (W. Liu et al, 2017 ; Ning et al, 2020 ; Schulik et al, 2023 ; Villata et al, 2023 ). As indicated by DoF measurements ( Figure 6A ), GelMA derived from Type A gelatin exhibits DoFs in the range between 90% and 95%, 94.73% ± 0.31% and 91.66% ± 0.17% for Method 1 and 2 syntheses, respectively, which can be considered similar in terms of performance.…”