Modeling flow behavior and flow rate of medium viscous alginate for scaffold fabrication with 3D bioplotter

Tissue regeneration with scaffold is one of the most promising approaches now a day, where application of dispensing-based rapid prototyping technique is drawing attention due to its capability to offer operational flexibility and print complex structure with utmost uniformity. In a pneumatic dispensing system, it is a critical issue to control the flow rate of biomaterial from dispensing tip, as some variables (material viscosity, temperature, needle geometry, and dispensing pressure) regulates the flow rate . In this context, model equations can play a vital role to control and predict the flow rate of dispensing material, and thus can eliminate the requirement of numerous time consuming trials during biofabrication. Therefore, in this study flow rate model has been developed for medium viscous alginate considering shear and slip flow from a tapered needle. In addition, model equations were also developed from regression of experimental data to predict the flow behavior of alginate at arbitrary concentration. Both flow behavior and flow rate model exhibited close agreement with experimental result, and therefore, indicate the accuracy of the developed model equations. In addition, the slip effect close to needle wall significantly influences the flow rate of alginate with the increase of dispensing pressure.