Biopolymer deposition for freeform fabrication of hydrogel tissue constructs

Three-dimensional (3D) tissue scaffolds play a vital role as extra-cellular matrices onto which cells can attach, grow, and form new tissue. Among available biomaterials, hydrogels, such as alginate, fibrin, and chitosan, have promising potential in tissue engineering applications because of their structural similarities to macromolecular-based human tissues, their biocompatibility, low toxicity, and availability. The presentation will report our recent research on development of a novel multi-nozzle biopolymer deposition system for freeform fabrication of biopolymer-based tissue scaffolds and cell-embedded tissue constructs. The process of the biopolymer deposition is conducted in a biocompatible environment which allows the construction of scaffolds with bioactive compounds and living cells. The system configuration and the process for fabrication of bioactive scaffolds through the biopolymer depositions system under different nozzle system will be described. Results of study on deposition feasibility and 3D structural formability of alginate-based tissue scaffolds will be reported. A semi-empirical model, developed based on the Poiseulle's equation for non-Newtonian fluids to predict the deposition flow rate and the deposition geometry, along with comparison of experimental data will be presented. Deposition of cell embedded tissue scaffold as well as the cell viability will be introduced. Results of effect of the process parameters on the structural, mechanical and cellular tissue engineering properties for freeform fabricated 3D alginate tissue scaffolds will also be presented.