Study of the Pulse of Peristaltic Pumps for Use in 3D Extrusion Bioprinting

Abstract

Peristaltic pumps are used in healthcare for their ability to aseptically displace various fluids, including medium-density gels and suspended solids. However, they have the undesirable characteristic of pulsing at their output. Three-dimensional printing is becoming a reality in tissue engineering, and it generally uses syringes to extrude hydrogels. One of the problems to be solved is the microdosing of biomaterials or bioinks when it is necessary to print large volumes. The use of peristaltic pumps in bioprinting is desirable as it does not limit the volume to the contents of a syringe while achieving dosage control. A peristaltic pump was designed and implemented to avoid pulsation errors and microliter dosing while allowing a large amount of fluid displacement. Two pumps with equal displacement were built. The first uses the conventional profile and is the baseline for comparisons, while the second presents the profile studied and proposed. The concepts demonstrated by Bernoulli were used, fixing the height of a column of water, while the two pumps provide flow to the system asynchronously, allowing the reading of pressure as a function of the speed variation created by the pulsation of each pump. An approximately 100 times reduction in pulsation was observed during fluid displacement with the variance reduced from 2.64 to 0.025 s ². The two pumps were also installed on a modified Ultimaker FDM 3D printer, and a standard for comparison was printed using a water-based hydrogel, corn starch, and corn-derived triglyceride, showing that the proposed pump improves the deposition quality of the material. Three-dimensional prints, tubes 20 mm in diameter by 8 mm in height and 0.7 mm in wall width, were also produced. Videos obtained show that the first pump was not able to print more than 4 mm in height, while the second prints the model with high quality and without deficiency. The results show that the new pump profile is able to provide a sufficiently constant volume for three-dimensional printing with excellent deposition control, building a simple object but difficult to obtain for a common peristaltic pump.