Novel self-assembly-induced 3D plotting for macro/nano-porous collagen scaffolds comprised of nanofibrous collagen filaments

•Self-assembly-induced 3D plotting was developed as an innovative SFF technique•Collagen scaffolds with a unique macro/nano-porous structure were produced.•Nanofibrous collagen filaments could be created through self-assembly of collagen.•The scaffolds had reasonable mechanical properties and excellent biocompatibility.

This study proposes self-assembly-induced 3D plotting as an innovative solid freeform fabrication (SFF) technique for the production of macro/nano-porous collagen scaffolds, particularly comprised of nanofibrous collagen filaments. In this technique, collagen filaments deposited in a coagulation bath could be effectively gelled through the self-assembly of collagen molecules into fibrils, accordingly, enabling the 3-dimensional deposition of collagen filaments with a collagen nanofiber network. The unique macro/nano-structure could be structurally stabilized by dehydration process coupled with chemical cross-linking. The porous collagen scaffolds produced had 3-dimensionally interconnected macropores (~ 451×305 μm in pore width) separated by nanoprous collagen filaments. In addition, the macro/nano-porous collagen scaffolds showed the tensile strength of~353 kPa and compressive strength of~31 kPa at a porosity of~95 vol% and excellent in vitro biocompatibility, assessed using pre-osteoblast MC3T3-E1 cells.