2.4. Determination of Cell Layer Integrity by Transepithelial Electrical Resistance (TEER) Measurements and Sugar Transport Quantitation

For cell layer integrity and sugar transport measurements, Caco-2 cells were seeded at 1.65 × 10⁵ cells/insert. Differentiation was induced the following day with Entero-STIM Intestinal Epithelium Differentiation Medium (Corning, Wiesbaden, Germany) supplemented with 100 μg/mL penicillin, 100 µg/mL streptomycin and 0.1% MITO + Serum Extender (Corning, Wiesbaden, Germany). Daily change of cell medium was followed by the experiment on day 5.

Differentiation of the monolayer was assessed by measuring transepithelial electrical resistance (TEER) of the cell monolayers. Only transwell inserts with a resistance exceeding 400 Ω were utilized in the experiments.