Biosurfactant-Stabilized Micropore-Forming GelMA Inks Enable Improved Usability for 3D Printing Applications

Purpose Three-dimensional (3D) bioprinting offers great potentials in rebuilding tissue mimics through engineering cell-laden constructs. Recently, the unique ability of a new type of micropore-forming bioink developed by us, containing two immiscible aqueous phases of gelatin methacryloyl (GelMA) and poly(ethylene oxide) (PEO), has become attractive since it promotes cellular behaviors. Nevertheless, this initial version of our two-phase aqueous emulsion bioink is generally unstable when experiencing prolonged storage times at room temperature, whereby it will phase-segregate and lose the micropore-forming capacity. This phase-segregation may lead to insufficient operational time window for bioprinting, especially for modalities that require a liquid-phase bioink such as digital light processing. Methods In this study, we report the development of a set of biosurfactant (rhamnolipids)-stabilized micropore-forming GelMA-based inks, with the goal of significantly improving their shelf-lives with enhanced applicability towards 3D printing. Results It was observed that the printed constructs using rhamnolipid-stabilized micropore-forming inks, either prepared fresh or stored for hours at room temperature, presented similar microporous structures. In contrast, the micropore-forming inks without biosurfactant-incorporation exhibited severely reduced performances after prolonged storage owing to marked phase-segregation. Conclusion Our study suggests that biosurfactant-incorporation enhanced stability of our micropore-forming GelMA inks and therefore present a wide range of possibilities in further development of two-phase aqueous emulsion inks and bioinks for future 3D printing and bioprinting applications. Lay Summary Three-dimensional (3D) bioprinting offers a collection of enabling technologies to address regenerative engineering and translational medicine problems, by allowing precisely controlled, automated fabrication of volumetric tissue constructs that are both structurally and functionally relevant to their counterparts in the human body. The biomaterials used for bioprinting are of significant importance to ensure proper tissue-production and maturation. We report a micropore-forming ink that is stabilized by biologically derived surfactant, in an effort to promote the stability of the resulting porous structures in 3D-printed architectures, for potential applications in tissue engineering and regenerative medicine.