Preparation of lipid-modulating 3D bio-inks stabilized by a ternary complex and optimal 3D printing conditions

A ternary complex was prepared using soy protein isolate (SPI), gallic acid (GA), and xanthan gum (XG) to produce 3D bio-inks with low, medium, and high lipid content as low, medium, and high internal phase emulsions (LIPE, MIPE, and HIPE, respectively), and the correlations between the chemical structure, rheological properties, and 3D printability of the 3D bio-inks were investigated. The successful synthesis of the ternary complexes was confirmed through significant changes in fluorescence, FT-IR, and XRD spectra. All 3D bio-inks exhibited stable structures for 5 weeks at 4, 25, and 500 °C. The 3D bio-inks showed differences in viscosity, recovery rate, and 3D printability depending on lipid concentration, which was confirmed by confocal laser scanning microscope (CLSM) images showing that the HIPE droplets were smaller and denser compared to other emulsions. All 3D bio-ink samples exhibited shear-thinning behavior and excellent recovery characteristics in creep tests and 3ITT, which enabled excellent 3D printability under optimal conditions. Collectively, the results of this study suggest that LIPE, MIPE, and HIPE 3D bio-inks stabilized with SPI/GA/XG can be utilized for lipid concentration control in the 3D bioprinting industry.