The test was performed in triplicates, with three samples of 3D printed discs (H 0.8 mm, Ø 5.5 mm) for each replicate. The 3D printed discs were washed with acetone for 30 min, followed with PBS pH 7.4 overnight, dried under vacuum for 24 h at room temperature, cured in UV chamber for 20 min, and soaked in medium for 20 min before the incubation. A549 cells were seeded in a 24-well plate with seeding density of 50,000 cells per well. The 3D printed discs were then put into the wells on the top of Transwell ® inserts. As positive control, cells were incubated in medium with 100 mM H2O2 while medium alone was used as a negative control. Cell viability was determined by the MTS assay after 48 ± 1 h of incubation (37 ± 1 °C, 5% CO2). The Transwell ® supports and medium were removed, the wells were washed with PBS and MTS reagent was added into the wells. Absorbance was measured after 45-60 min of incubation (until A=0.6-0.8) using a spectrophotometric plate reader (490 nm, TPP24fT, without lid, linear shaking 10 s, amplitude 1.5 mm, number of flashes 25, settle time 5 ms).