3D Printing of Collagen Scaffold with Enhanced Resolution in a Citrate-Modulated Gellan Gum Microgel Bath

3D printing in a microgel-based supporting bath enables the construction of complex structures with soft and watery biomaterials but the low print resolution is usually an obstacle to its practical application in tissue engineering. Herein, high-resolution printing of a 3D collagen organ scaffold is realized by using an engineered Gellan gum (GG) microgel bath containing trisodium citrate (TSC). The introduction of TSC into the bath system not only mitigates the aggregation of GG microgels, leading to a more homogeneous bath morphology but also suppresses the diffusion of the collagen ink in the bath due to the dehydration effect of TSC, both of which contribute to the improvement of print resolution. 3D collagen organ structures such as hand, ear, and heart are successfully constructed with high shape fidelity in the developed bath. After printing, the GG and TSC can be easily removed by washing with water, and the obtained collagen product exhibits good cell affinity in a tissue scaffold application. This work offers an easy-to-operate strategy for developing a microgel bath for high-resolution printing of collagen, providing an alternative path to in vitro 3D organ construction.

Automated summary

3D printing with a microgel-based supporting bath allows the construction of complex structures using soft and watery biomaterials, but low print resolution has limited its practical applications in tissue engineering. In this study, high-resolution printing of a 3D collagen organ scaffold was achieved by using an engineered Gellan gum (GG) microgel bath containing trisodium citrate (TSC). The addition of TSC improved the bath's morphology and suppressed collagen ink diffusion, leading to improved print resolution. Successfully printed collagen organ structures demonstrated high shape fidelity, and the resulting collagen products showed good cell affinity in tissue scaffold applications.