Table 2.

The concentration of extract (CE₅₀) obtained from Cur_Cu_4%, Cur_Cu_6%, and Cur_Cu_8% biomaterials, which is required to inhibit E. coli or S. aureus growth to 50%. The CE₅₀ values were calculated via 4-parameter nonlinear regression analyses, GraphPad Prism 5, version 5.04).

Biomaterial Used to Obtain Extract in Mueller-Hinton Broth (MHB)	Concentration of Extract Required to Inhibit Bacterial Growth to 50% (CE50) [%]
	E. coli	S. aureus
Cur_Cu_4%	76.48 ± 1.45	ND *
Cur_Cu_6%	66.73 ± 2.34	ND *
Cur_Cu_8%	46.65 ± 2.21	65.86 ± 2.12

* ND—not determined. All tested concentrations of extract did not exhibit ability to inhibit bacterial growth to 50%.