Figure 7.

Human periodontal/osteoblastic microtissue exposed to tetracycline in microfluidic culture. (A) Cell viability of the constructs exposed to different doses of tetracycline (0–1.0 μg/mL) was measured by Alamar blue assay, and the groups were compared with time change using the two-way ANOVA and Bonferroni post-hoc test (∗P < 0.05) for n ≥ 3 individual repeats. (B) Representative histology images of the layered microtissues exposed to 1.0 μg/mL tetracycline in microfluidic culture for 3 and 7 days. Micrographs demonstrate homogeneous distribution of cells encapsulated inside the bioprinted constructs. PAS-stained (magenta-coloured) denser matrix with lesser empty spaces in the sections at day 7 (compared with day 3) resembles the production of glycosaminoglycans. (C) Tetracycline absorption levels of the perio/osteo microtissues inside microfluidic chip. The data was normalized to cell-devoid 3D-printed gels. Groups were compared using the one-way ANOVA and Bonferroni post-hoc tests (∗P < 0.05). (D) CLM images of the periodontal/osteoblastic microtissues retrieved after 1, 3 and 7 days of microfluidic culture containing tetracycline, indicating the viability of cells at all time-points. Green staining apparently shows the uptake of the calcein reagent by the living cells. Dead cells stained in red color (ethidium homodimer labelling) are rarely observed even after 7 days.