Universal Strategy for Regulating Protein‐Based High Internal Phase Emulsions as 3D Printing Materials

Abstract Protein‐stabilized high internal phase emulsions (HIPEs), which are pseudoplastic fluids with shear thinning and high viscoelasticity, are suitable for 3D printing inks. However, owing to the lack of a universal approach to the 3D printing of HIPEs, existing printing materials are unable to meet the developmental, biocompatibility, and safety requirements of various applications. Herein, it is demonstrated that post‐acidification of protein HIPEs enhances 3D printing performance. This method has the advantage of breaking through protein limitations, pH, and other environmental factors. The self‐supporting property required for 3D printing is achieved through the self‐assembly of continuous‐phase proteins into particle aggregates, and interfacial stability is maintained owing to the constant interfacial tension and contact angle. The acid‐induced protein aggregates in the continuous phase do not affect the stability of the modified HIPEs. This work provides a valuable new idea for advancing the application of protein HIPEs in 3D printing through a post‐acidification strategy.