Rapid freeze prototyping technique in bio-plotters for tissue scaffold fabrication

Purpose - The purpose of this paper is to develop a new bio-plotter using a rapid freeze prototyping (RFP) technique and to investigate its potential applications in fabricating tissue scaffolds. Design/methodology/approach - The development of cryogenic bio-plotters including design steps of hardware as well as software is addressed. Effects of structural parameters and process parameters on the properties of tissue scaffolds are demonstrated through simulation and experimental results. Findings - The paper finds that the RFP method is suitable to fabricate macro- and micro-porous scaffolds, especially for temperature-sensitive polymers. In addition, through simulation and experiment results, it also shows that macro- and micro-porous properties could be manipulated by structural parameters and process parameters, respectively. Research limitations/implications - This paper shows that the chamber temperature is an important process parameter that can provide the means to control the micro-porous structure of the scaffold. However, if the temperature is set too high, the fiber is frozen so rapidly that it cannot be fused with other fibers of the previous layer. On the other hand, if the temperature is too low, the fiber is not solidified fast enough. So, the chamber temperature, together with extruding pressure and nozzle velocity, must be optimized, which will be further investigated in future work. Originality/value - The RFP technique is successfully proposed to construct 3D tissue scaffolds. In addition, a new cryogenic bio-plotter is designed and developed, in which general algorithms of rapid prototyping method are presented and implemented, facilitating the fabrication of tissue scaffolds with various cross-hatching patterns in a RFP process.