Table 2. Surface roughness measurements (R_rms) of PS, PDMS, and ParC/PDMS substrata before and after surface treatment.

Root-Mean-Square Roughness (Rrms, nm)
Substratum	O2- plasma treated	O2 plasma + type-I collagen treated
PS	1.5±0.1	2.2±0.4
PDMS	0.4±0.1	0.9±0.2
ParC/PDMS	4.6±0.3	7.1±0.9

Data are represented as mean of nine values obtained from three separate experiments.