Human colorectal adenocarcinoma cell line DLD-1 (ATCC® CCL221™), kindly provided by AREKO Ltd., Prague, Czech Republic, and human breast adenocarcinoma cell line MCF-7 were used. Cells were cultivated at 37°C in a humidified incubator with 3.5% in standard medium (Eagle’s minimum essential medium based on Hanks balanced salt solution enriched with nonessential amino acids and 1 mM sodium pyruvate, with 1 g , 10% calf serum, 80 mM gentamicin, and 2 mM L-glutamine). Observation medium F10 was prepared without phenol red. 20 mM TES (N-[tris(hydroxymethyl)methyl]-2-aminoethanesulfonic acid, 2-[(2-hydroxy-1, 1-bis(hydroxymethyl)ethyl)amino]ethanesulfonic acid) buffer (Sigma T5691) was used to set a pH of 7.4. For microscopy, trypsinized cells were seeded in subconfluent density and hermetically closed in the static observation chamber (Figs. 2, 3, 5, and 6), which consists of two coverslips and an annular ring spacer. The volume of the chamber is 0.7 ml with 4 mm inner height for BAPs preparation in emulsion, which constitutes the strong diffusing layer between the coverslips. For observation in perfusion mode with online changes of medium (Fig. 4), the -Slide I Leuer flow chamber (Ibidi Company) with 0.8 mm inner height was used. Cells were measured under standard laboratory conditions. A temperature of 37°C was constantly maintained in the environmental box for CCHM.