Table 1.

Graphene oxide modifications with the objective of gene transfection.

GO Modification	Modification Mechanism	Agents
Covalent	Amidation	PEG [62,63,77,86]
		PAMAM [16,17,87]
		PEI [88,89]
		Chitosan [64,65,66]
		DEX [90]
	Ring-opening reaction	PEG [17]
		APTES [53]
	Esterification	PEG [91]
Non-covalent	π-π stacking	MUC1 aptamer [72]
	Electrostatic interactions	PEG [67,70]
		PEI [67]
	Hydrophobic interactions	Phospholipids [52,70]