Table 1. Intracellular concentration of Ca²⁺ ([Ca2+]_i nM).

days	Proliferative medium (PM)		Osteogenic medium (OM)
	TiO2	TiO2/PEMF+	TiO2	TiO2/PEMF+
3	63 ± 5 (§) (**)	87 ± 2(# #) (***)	105 ± 2(**)	155±2 (***) (# #)
28	69 ± 7 (§) (**)	192 ± 8(# #)	299 ± 11(**)	293 ± 9(**)

Intracellular concentration has been analysed performing Ca²⁺ Fura-2 measurements in hBM-MSCs. The trend of different cell populations growing adherent to TiO₂ was monitored after 3 days and at the end of the culture (28 days). The data, representing the results of three measurements in two separated experiments, are expressed as the mean ± SEM (** p < 0.01 vs. cultures grown on TiO₂ (§)). Similar values were also obtained in ref [12] even though from different experiments and at different checkpoints. Data represent the results of three sets of independent experiments and are expressed as mean ± SEM (** p < 0.01 and *** p< 0.001 vs. cultures grown on glass in PM; ^## p < 0.01 vs. cultures grown on TiO₂).