The present invention relates to biomaterial in the form of dispersion of cellulose nanofibrils with extraordinary shear thinning properties which can be converted into desire 3D shape using 3D Bioprinting technology. In this invention cellulose nanofibril dispersion, is processed through different mechanical, enzymatic and chemical steps to yield dispersion with desired morphological and rheological properties to be used as bioink in 3D Bioprinter. The processes are followed by purification, adjusting of osmolarity of the material and sterilization to yield biomaterial which has cytocompatibility and can be combined with living cells. Cellulose nanofibrils can be produced by microbial process but can also be isolated from plant secondary or primary cell wall, animals such as tunicates, algae and fungi. The present invention describes applications of this novel cellulose nanofibrillar bioink for 3D Bioprinting of tissue and organs with desired architecture.