A study on cell viability based on thermal inkjet three-dimensional bioprinting

Abstract

Thermal inkjet three-dimensional (3D) bioprinting (TIJ) is a biological additive manufacturing technology with high cell viability, fast printing speeds, and low costs. It is widely used in biology, chemistry, and pharmaceuticals. In recent years, remarkable results have been achieved in the printing of biological tissues using TIJ. However, few studies have reported on the relationship between TIJ and cell viability. In particular, there have been no reports relating cell viability and the TIJ input energy. In this work, we aim to determine the relationship between the input pulse, printing frequency, and cell viability from the TIJ working principle and find an optimized pulse waveform to improve cell viability. We propose a novel approach to study cell viability. The state of the droplet is observed while controlling the printing pulse and frequency, and then, the corresponding cell viability is determined. The results show that an increase in the pulse increases the shear stress and temperature in the bio-ink, which reduces the viability of the cells. The shear stress and viability of the printed cells show a corresponding piecewise functional relationship. The cell viability is significantly reduced when the ambient temperature is higher than 40 °C. Increasing the printing frequency reduces the rate of printing heat loss, thereby raising the ambient temperature and impairing cell viability. Finally, the optimized input waveform can increase cell viability by up to about 95%.