DLP requires low viscosity inks to ensure the fluid can flow away from the cured material and hollow parts while the printing stage is lifted, and to allow refill of the ink under the raised scaffold for recoating. While literature reports show DLP of inks with viscosities between 4 and 2000 mPa s, a viscosity <100 mPa s is considered more advantageous for good printability. In our study, HA-X solutions at 4% w/v in PBS showed viscosities well below 100 mPa s (Figure ) and, therefore, were considered suitable for DLP. Within the tested conditions, the hydrogel precursor solutions mostly exhibited a Newtonian behaviour i.e. constant viscosity with varying shear rate which is characteristic of diluted polymer solutions. While HA-AE possess an overall lower viscosity than native HA, the viscosity of HA-NB and HA-MA is higher.