ETD

• 3D bioprinting
• 3D tumor model
• biomaterials
• foam
• polymers

In 3D bioprinting, the construction of cell-laden scaffolds relies on precise deposition of bioink layers to generate hydrogel matrices in which cells are embedded. High porosity is essential to efficiently support cell growth and proliferation. Unfortunately, conventional hydrogel-based bioinks tend to have rather low inner porosity, which limits their effectiveness in biological applications. To overcome this limitation, in this project we developed porous bioinks based on alginate–albumin foams, using a pneumatic extrusion bioprinting approach. Such scaffolds were designed for the fabrication of a three-dimensional (3D) tumor model.
The bioinks were formulated by combining sodium alginate (SA) with two proteins of different origin, namely, bovine serum albumin (BSA) and egg white ovalbumin (Ov). The components were blended mechanically in a high-speed flask using an overhead stirrer equipped with a custom-designed half-moon blade to generate stable foams. To further improve foam stability without compromising cytocompatibility, sodium dodecyl sulphate (SDS) was also introduced as a surfactant.
Optimal working concentrations were determined, and successful operating parameters were identified, starting with an in-depth investigation to identify the most suitable type of SA and albumin, and their optimal concentrations. The resulting bioinks were cross-linked with calcium chloride solutions and their morphology, rheological behaviour, printability, porosity, gel fraction, and swelling capacity were evaluated.
Finally, to explore their biological potential, the cell/bioink constructs were tested in vitro with intestinal-type adenocarcinoma (ITAC) cells, confirming the promise of these porous foams as functional bioinks for 3D tumor modelling.