Table 1.

Concentration (in at. %) of carbon (C), oxygen (O), nitrogen (N) and sulfur (S), determined by XPS analysis, on HDPE and LDPE treated with plasma for 50 s (50), and subsequently grafted with fibronectin (Fn) and bovine serum albumin (BSA). Mean from three measurements for each experimental group; the measurement error did not exceed 5%.

Material/Modification	HDPE				LDPE
	C (at. %)	O (at. %)	N (at. %)	S (at. %)	C (at. %)	O (at. %)	N (at. %)	S (at. %)
50	82.2	14.2	2.5	0	83.0	14.8	1.5	0
50 Fn	72.9	20.2	6.7	0.2	82.2	13.6	2.8	at limit of detection
50 BSA	74.4	15.3	9.9	0.4	72.7	15.3	10.9	0.4