Mussel-inspired multifunctional coatings on biomedical devices have been a great interest due to its unique property, such as substrate indendency and high efficiency. The key molecules for mussel-inspired adhesive coatings are catechol and amine groups. Along with the understanding of catechol chemistry, chitosan-catechol has been also developed as a representative mussel-inpired adhesive polymer that has catechol and amine groups for adhesiveness. Herein, we demonstrated the direct writability of chitosan-catechol as a bioink for 3D printing, one of additive techniques. The use of chitosan-catechol bioink resultes in 3D constructs in the normal culture media by rapid complexation with serum proteins. In addition, the metal/catechol combination containing tiny amounts of vanadyl ions, which is the ratio to catechol of 0.0005, dramatically enhances the mechanical strength and printability of the cell-encapsulated inks, showing approximately 90% of cell viability. These findings for mussel-inspired bioinks would be a promising way to design the biocompatible 3D bioink crosslinked without any external stimuli.