Effect of process parameters of the positive displacement pump for extrusion based bioprinting application

Abstract

Bioprinting is an emerging technology that provides the ability to fabricate customized tissue constructs. One of the most common methods is Extrusion Based Bioprinting (EBB) which allows extruding high viscosity materials at a low cost. While currently available EBB methods provide an acceptable extrusion process, several disadvantages remain a challenge such as low extrusion accuracy in terms of start and stop accuracy. The present study aimed to explore the relationship between the extrusion accuracy and syringe features including plunger rubber compressibility and amount of volume inside the syringe. The weighing scale and the flow rate sensor are used to assess the extrusion accuracy. Results show that the plunger rubber has a negative impact on extrusion accuracy due to its compressibility.  Likewise, when the amount of compressed volume inside the syringe increases, the start and stop accuracy of extrusion decreases. The time required to reach desired flow rate was measured as 17, 25, 29 seconds (±0.5) for 20, 30 and 40 ml filled syringe volumes respectively. The findings can contribute to a better understanding of the positive displacement pump and the extrusion accuracy relationship. As a result of these investigations, suggestions for a better extrusion pump were identified for future research.