2.4. Treatment to Replenish the Ions Concentration

Part of the probes was exposed after lanthanoid treatment with the following solutions sequentially:

0.9% NaCl solution—wash out remaining REE ions;

PBS, pH 7.4—returning Pi;

HBSS with Ca²⁺ and Mg²⁺ (the concentration of Ca²⁺ in this solution was increased to 3.9 mM)—returning calcium ions;

0.9% NaCl solution—wash out of excess calcium;

Growth medium (RPMI-1640 with 10% FBS).

In a time-lapse confocal microscopy study, the cell medium was replaced by Bio-REE solutions and then returned back directly during the microscope session.