**Cell VI Abilities**

**Chapter 11**

**Provisional chapter**

**3D Bioprinting: Surviving under Pressure**

**3D Bioprinting: Surviving under Pressure**

DOI: 10.5772/intechopen.73137

Because 3D bioprinting using microextrusion was reported to yield cells with low viability (~40%) after pneumatic pressure (40 psi) printing through stainless steel nozzles, or blunt-end needles, with about 150 μm diameters (28 and 30G), we set out to improve the viability by coating the interior of the nozzles with silicone. For these studies, H9 human lymphoma cells were used to simulate human stem cells in suspension, and cell viability was measured using propidium iodide dye exclusion and flow cytometry. We tried to improve the viability by coating the inside of the 28 and 30G nozzles (1″ length) with silicone to protect the cell membranes from being damaged by the imperfections in the stainless steel nozzle. However, we discovered silicone coating had little effect on viability because imperfections in the nozzle were not the problem. Instead, the cells being placed in hypotonic 3% (w/v) alginate prepared in water prior to printing caused significant cell death (~25%) and considerably more (≥50%) after simulated printing under pressure. By preparing the alginate in isotonic solutions of either phosphate buffered saline or complete culture media, we could use pressures over five times (>220 psi) what most printing

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution,

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

and reproduction in any medium, provided the original work is properly cited.

3D bioprinting is the wave of the future for constructing viable, functional, and biocompatible human organs that will be created from the patient's own stem cells so that antirejection drugs will not be needed after transplantation. Currently, there are three main 3D bioprinting

Inkjet printing uses thermal or acoustic (piezoelectric) forces to create and eject droplets. Thermal inkjet bioprinting yields good cell viability (>85%), and although localized heating of 200–300°C occurs and the temperature at the head only rises 4–10°C for short durations

Additional information is available at the end of the chapter

procedures use and obtain ~80% viability.

**Keywords:** force, hydrogel, hypotonic, isotonic, microextrusion, viability

methods: inkjet or "drop on demand," laser-assisted, and microextrusion [1].

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.73137

Dianne Eyvonn Godar

**Abstract**

**1. Introduction**

Dianne Eyvonn Godar

**Provisional chapter**
