26. BIOPRINTING VASCULAR GRAFTS WITHOUT SUPPORT MATERIAL: A COMPARISON BETWEEN NEW AND COMMERCIAL HYDROGEL

Abstract

Abstract Introduction Currently, the demand for personalized vascular grafts is increasing and bioprinting techniques emerge as a promising approach for its development. The aim is to comparatively evaluate the performance of a Gelatin/Gellan Gum/Alginate hydrogel and a commercial bioink to produce bioprinted vascular grafts without support material. Methods Two hydrogels were employed in this study: a custom-made Gelatin/Gellan Gum/Alginate (8:3:0.5 %w/v) and a commercial bioink (Cellink Bioink) consisting of 5% alginate with nanocellulose. Three experiments were conducted to assess their performance. The first experiment involved diluting the commercial hydrogel in PBS at a 1:10 ratio. The second experiment applied the commercial hydrogel without dilution, while the third experiment utilized the custom-made hydrogel without dilution. Optimal printing conditions were established for both hydrogels, with the Cellink bioink set to 37 °C, 10 kPa, and 7 mm/s, and the Gelatin/Gellan Gum/Alginate hydrogel set to 50 °C, 45 kPa, and 9 mm/s. For each hydrogel, three grafts were printed, each with dimensions of 15 mm height, 500 μm wall-thickness, and a 6 mm inner diameter. The physical characteristics of these grafts were subsequently measured using an optical microscope. Results Results showed differences between the three experiments. Vascular grafts produced with Gelatin/Gellan Gum/Alginate hydrogel present a wall-thickness and an inner diameter of 553±150 μm and 5.33±0.24 mm, respectively. In contrast, the commercial bioink from Cellink failed to facilitate the production of vascular grafts, as it fully collapsed at layer 17 out of 37. Conclusion The Gelatin/Gellan Gum/Alginate hydrogel proves to be effective in bioprinting vascular grafts, demonstrating both adequate accuracy and structural stability. Notably, it distinguishes itself from commercial bioinks by not necessitating additional sacrificial materials in the process.