Fig. 4.

a HL-60 cells on the second cultivation day in either 5-days-old medium (open circles, n = 10) or in pH-reduced fresh medium (full triangles, n = 22). The two media had the same pH value but different effects on the cellular stiffness. The fresh medium was the decisive factor in the HL-60 cell rigidity, as shown in (b). Here, the two 5-days-old HL-60 populations exhibited the same electric deformation, although the pH values of the media were different. Both populations were cultivated in fresh medium for 24 h (n ≥ 13)