Biocompatible structure, and fabricating methods and applications of same

A biocompatible structure useable for tissue regeneration, comprising:

• a scaffold obtained by treating a three-dimensional (3D) structure, the 3D structure comprising one or more base layered structures,
• wherein each base layered structure comprises at least a first layer and a second layer surrounded by the first layer, wherein the first layer and the second layer are formed of different materials, the first layer comprises a first composition comprising at least one of a first medium, a second medium and a third medium, and the second layer comprises a second composition comprising at least another of the first medium, the second medium and the third medium;
• wherein the first medium comprises bone particles, the second medium comprises a polymer that is dissolvable or removable in a first solvent, and the third medium comprises solid particulates that are dissolvable or removable in a second solvent different than the first solvent;
• wherein each base layered structure is formed by co-extruding the first composition and the second composition from a multi-nozzle deposition system comprising an outer extruder nozzle and an inner extruder nozzle disposed concentrically or eccentrically inside the outer extruder nozzle, wherein the first layer is formed by the outer extruder nozzle and the second layer is formed by the inner extruder nozzle such that the second layer is entirely surrounded by the first layer in the cross-section of said base layered structure;
• and
• wherein the 3D structure is treated with the second solvent to dissolve the solid particulates of the third medium therefrom so as to remove the solid particulates from the 3D structure and form pores at positions of the solid particulates therein, thereby resulting in the scaffold having a porosity that is adjustable by sizes of the solid particulates and concentration of the solid particulates in the 3D structure.