With sodium alginate as raw material and calcium chloride as crosslinker

a hollow hydrogel fiber was fabricated by direct writing combined with crosslinking

and was used to construct tissue engineering scaffold. Fiber gel fraction and swelling degree directly affect the forming quality of scaffold and laden cell survival. The influence of materials concentration on gel fraction was analyzed by leaching the ungelled part from the fiber. As a control group

alginate beads were prepared with coagulating bath. The requirements of direct writing process

such as gel rate

gel fraction and fiber morphology were satisfied

when the concentration of sodium alginate and calcium chloride were 4% and 3% respectively. With increasing sodium alginate's concentration

equilibrium swelling degree of hollow fiber first decreased and then slightly increased and stabilized finally. With increasing calcium chloride's concentration

swelling degree gradually decreased. Due to smaller diffusion interface

swelling degree of hollow fiber was two to five times higher than the gelled beads

and higher moisture was in favor of the viability and mass transfer for cell laden.