Table 3.

Adhesion energies and maximum pull-off forces for HepG2 cell interactions with uncoated, APTES-coated, and PEI-coated glass probes after 1 s (a), 10 s (b), and 30 s (c) contact times. The radii of used colloidal probes (µm) are presented in (d). Mean values and standard errors of the mean (SEM) are shown.

a	HepG2 – controls, 1 s contact						b	HepG2 – controls, 10 s contact
	Number of force curves analyzed	Normalized adhesion energy (nJ/m)	SEM (nJ/m)	Adhesion energy (fJ)	Maximum pull-off force (mN/m)	SEM (mN/m)		Number of force curves analyzed	Normalized adhesion energy (nJ/m)	SEM (nJ/m)	Adhesion energy (fJ)	Maximum pull-off force (mN/m)	SEM (mN/m)
Glass	18	0.023	0.007	0.36	0.011	0.002	Glass	17	0.030	0.007	0.46	0.015	0.002
APTES	12	0.043	0.008	0.56	0.018	0.002	APTES	6	0.090	0.042	1.18	0.042	0.013
PEI	7	0.66	0.19	7.22	0.150	0.048	PEI	5	0.45	0.19	4.88	0.086	0.027
c	HepG2 – controls, 30 s contact						d	Radii (µm) of control probes
	Number of force curves analyzed	Normalized adhesion energy (nJ/m)	SEM (nJ/m)	Adhesion energy (fJ)	Maximum pull-off force (mN/m)	SEM (mN/m)
Glass	15	0.083	0.020	1.30	0.032	0.005		HepG2	Glass	15.6
APTES	7	0.172	0.026	2.24	0.124	0.026			APTES	13.1-13.5
PEI	7	1.14	0.32	12.5	0.31	0.11			PEI	11.0-13.4