Freeform fabrication of bioactive tissue scaffolds

Biopolymeric scaffolds have been utilized in tissue engineering as a technique to confide the desired proliferation of seeded cells in vitro and in vivo into its architecturally porous three-dimensional structures. Novel freeform fabrication methods for tissue engineering polymeric scaffolds have been an interest because of its repeatability and capability of high accuracy in fabrication resolution at the macro and micro scales. A multinozzle biopolymer deposition system which is capable of extruding biopolymer solutions and living cells for bioactive fabrication of 3D tissue scaffolds is presented. The deposition process is biocompatible and occurs at room temperature and low pressures to reduce damage to cells. Sodium alginate aqueous solution is deposited into calcium chloride solution using three-dimensional dispensing (3DD) to form hydrogel structures. The flow rate, nozzle diameter, and nozzle velocity were studied and a model was developed to design 3D scaffolds with controlled strut diameters and pore sizes. In addition, cells were deposited through the system with alginate to form gel scaffold structures with encapsulated cells in a bioactive fabricated manor. Cell viability studies were conducted on the cell encapsulated scaffolds for validating the bioactive freeform fabrication process.