Table 1.

Atomic percentages of the elements determined by X-ray photoelectron spectroscopy (XPS) analysis.

Sample Name	(C), at.%	(O), at.%	(N), at.%	(Ca), at.%	(Na), at.%	(Ti), at.%
PCL-ref	76.0	24.0	0.0	0.0	0.0	0.0
PCL–TiCaPCON	55.4	22.5	8.6	1.1	0.0	8.4
PCL–COOH	77.0	23.0	0.0	0.0	0.0	0.0
PCL–COOH-12h	75.0	22.0	1.1	1.5	0.4	0.0
PCL–COOH-24h	77.3	20.1	1.0	1.2	0.3	0.0
PCL–COOH-72h	78.2	18.4	2.4	1.0	0.0	0.0