Table 1.

XPS determined atomic composition and high resolution carbon peak fits of the functionalized substrates used in this study. (b) bare silicon nitride, (a) silicon nitride treated with ethanolamine, (ap) silicon nitride treated with ethanolamine and NHS–PEG–PDP, (bp) silicon nitride with NHS–PEG–PDP, and (ScpB) silicon nitride treated with ethanolamine, NHS–PEG–PDP and ScpB.

	Atomic composition				High-resolution carbon peak fit
	C	N	O	Si	CH	CN/CO	COO/CON
b	14.1(1.1)	23.7(0.9)	32.1(0.5)	30.1(0.5)	72%	18%	10%
a	13.7(0.7)	23.8(0.3)	32.6(0.3)	30.0(0.6)	65%	25%	10%
ap	15.0(1.1)	23.9(1.3)	31.4(0.8)	30.5(0.3)	43%	41%	16%
bp	15.4(1.8)	22.7(0.8)	32.7(0.9)	29.2(0.9)	42%	38%	20%
ScpB	32.9(1.3)	16.5(0.7)	28.7(1.2)	21.9(0.8)	44%	33%	23%