TABLE III.

Extracted number of layers $n_{\mathit{p}\mathit{r}\mathit{o}\mathit{t}}$ of protein. “X” means the coupling method does not apply with the specified particle.

Coupling	PS	PS-COOH	$Si{O}_2$	$Si{O}_2$-COOH
$n_{\mathit{p}\mathit{r}\mathit{o}\mathit{t}}$ (Adsorption)	4	27	38	12
$n_{\mathit{p}\mathit{r}\mathit{o}\mathit{t}}$ (Covalent coupling)	X	1	X	1
Normalized ${\epsilon }_{\mathit{p}\mathit{r}\mathit{o}\mathit{t}}$	1.99 ± 0.12	1.97 ± 0.09	2.20 ± 0.21	1.99 ± 0.15