Uptake of label-free graphene oxide by Caco-2 cells is dependent on the cell differentiation status

Table 1 Overview on the physicochemical properties of applied graphene oxides and graphene nanoplatelets

	Graphene oxide		Graphene nanoplatelets
	GO-1	GO-3	GNP
Material source	Commercial	Research	Commercial
Preparation method	Modified hummers method	Modified hummers method	Microemulsion
Starting material	Graphite	Natural graphite	Natural graphite
State as received	Powder	Dispersion	Powder
Lateral dimensions	1–40 µm (SEM)	150 nm ± 44 nm (AFM)	Aggregate size 1–10 µm; mean ~5 µm (SEM)
Number of layers	Single to few layer	Single layer	Aggregate thickness <5 µm
C/O ratio (XPS)	1.7 ± 0.1	1.9 ± 0.1	24.0 ± 2.5
Dispersion in …	Ultra-pure water	Ultra-pure water	0.1 mg/ml sodium cholate in ultra-pure water
Dispersion colour	Brown	Brown	Anthracite
Zeta-potential in ultra-pure water	−39.4 ± 1.3 mV	−43.9 ± 1.4 mV	−62.6 ± 1.9 mV

Overview on the physicochemical properties of the applied label-free graphene-related materials (GRM) as determined by Kucki et al. [20]. Original material acronyms were retained for sake of clarity

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