To develop a gelatin-gellan composite scaffold of complex shapes having multiscale porosity using a combination of cryogenic 3D printing and lyophilization for bone tissue engineering.
Cryogenic 3D printing is used to fabricate low concentration composite of gelatin-gellan complex-shaped structures with macroporosity of pore size 919 ± 89 µm. It is followed by lyophilization to introduce microporosity of pore size 20-250 µm and nanometre level surface functionalities, thus achieving hierarchical porous structure. These multiscale porous scaffolds (GMu) are compared with two other types of scaffolds having only microporosity (GMi) and macroporosity (GMa) for their physical and in vitro biological properties. GMu scaffolds are found better in terms of swelling%, degradation rate, uniform pore distribution, cellular infiltration, attachment, proliferation, protein generation, and mineralization than GMi and GMa.
A controlled hierarchical bone-like structure, biomimicking natural bone, together with a simple process of manufacture is developed by coupling soft hydrogel 3D printing with lyophilization. This enables the development of complex-shaped patient-specific 3D printed hydrogel scaffolds that showed enhanced performance in vitro and great potential in the field of tissue engineering, bioprinting, and regenerative medicine.

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