Fig. 8
Glucose as a noninvasive indicator of luminal coverage of in vitro preconditioned TEVG. Glucose measured on the last timepoint of the static cultivation did not show a significant correlation to the estimated luminal coverage, probably due to the dynamic cultivation washing out the cells (A). Lactate behaved similarly (B). Glucose as measured on day 9 of dynamic cultivation indirectly correlated significantly to the estimated luminal coverage, confirming its validity as a noninvasive indicator (R2 = 0.4877, r = − 0.6983, 95% CI: − 0.9022 to − 0.2395, p = 0.0079) (C), and lactate directly correlated with the luminal coverage (R2 = 0.5328, r = 0.73, 95% CI: 0.2994 to 0.9135, p = 0.0046) (D). The ROC curve analysis revealed glucose greater than 62 mg/ indicates LC > 60%, with a 100% sensitivity and 87,5% specificity (Youden’s Index = 0.8571) (E). Lastly, bioburden analysis of the cell supernatant on the last day of cultivation revealed lack of contamination at both 425 nm (F) and 600 nm (**, p < 0.01; ****, p < 0.0001) (G)