Bioactive Surface Modification of Hydroxyapatite

Table 1

XPS-determined binding energies (eV) of Ca 2p, P 2p, and Δ(Ca 2p, P 2p); atomic concentrations (at. %); and Ca/P ratios for hydroxyapatite (HAP) and HAP treated with 10%, 20%, 30%, 40%, 50%, or 60% phosphoric acid (HAP—10% PA, HAP—20% PA, HAP—30% PA, HAP—40% PA, HAP—50% PA, and HAP—60% PA).

Sample		Binding energy (eV)			At. %				Ca/P
		Ca 2p	P 2p	Δ(Ca 2p, P 2p)	C 1s	O 1s	Ca 2p	P 2p
HAP	Mean	346.51	132.45	214.06^a	26.81	47.74	15.84	9.61	1.65
	SD	0.03	0.05	0.05	2.02	1.35	0.50	0.31	0.02
HAP—10% PA	Mean	346.87	132.80	214.07^a	11.04	58.00	18.80	12.17	1.54^c
	SD	0.05	0.05	0.05	1.06	0.58	0.34	0.18	0.01
HAP—20% PA	Mean	346.77	132.72	214.05^a	15.70	54.75	17.77	11.78	1.51^b
	SD	0.09	0.09	0.05	6.12	3.76	1.52	0.84	0.02
HAP—30% PA	Mean	346.61	132.54	214.07^a	25.80	49.32	14.92	9.96	1.50^b
	SD	0.06	0.07	0.05	1.09	1.36	0.58	0.54	0.03
HAP—40% PA	Mean	346.85	132.79	214.06^a	9.94	57.77	19.66	12.63	1.56^c,d
	SD	0.05	0.07	0.05	0.83	0.61	0.18	0.11	0.02
HAP—50% PA	Mean	346.91	132.88	214.03^a	11.10	57.48	19.19	12.24	1.57^c,d
	SD	0.07	0.08	0.05	1.80	1.10	0.56	0.25	0.04
HAP—60% PA	Mean	346.73	132.68	214.05^a	10.93	57.78	19.18	12.11	1.58^d
	SD	0.05	0.04	0.05	0.32	0.26	0.12	0.12	0.02

The presence of the same superscript letter for the values indicates that there were no significant differences among the samples (P > 0.05).