Table 1.

A selected list of ZnO-based biosensors which use immobilized enzymes.

Analyte	ZnO Nanostructure	Immobilization Mode	Detection Limit (μM)	References
	Nanocombs	Physical adsorption	20	[79]
	Nanowires	Physical adsorption	0.7	[84]
	Nanowire arrays	Physical adsorption	100	[85]
	Nanorods	Electrostatic	10	[86]
	Nanonails	Electrostatic	5	[87]
	Tetragonal pyramid- shaped porous ZnO nanostructures	Physical adsorption	10	[88]
Glucose	Nanorods	Crosslinking	0.01	[89]
	Nanoclusters	Crosslinking	20	[90]
	Carbon decorated	Physical adsorption	1	[91]
	Nanowires
	Nanoparticles	Physical adsorption	2.2	[93]
	Nanocrystals	Covalent bonding	330	[94]
	Nanowires	Covalent bonding	140	[92]
	ZnO sol-gel matrix	Electrostatic	0.08	[98]
	Nanoparticles	Electrostatic	0.05	[99]
	Nanorods	Electrostatic	15.6	[100]
Phenol	Nanorod cluster	Electrostatic	0.5	[101]
	Nanorods	Electrostatic	0.63	[102]
	Nanorod microarray	Covalent bonding	0.25	[103]
	Nanofilm	Encapsulation	0.047	[104]
	Nanoflower	Entrapment	2.0	[106]
H2O2	Nanorods	Chemical adsorption	0.12	[107]
	Nanorods on gold wire	Physical adsorption	5	[108]
	Nanoporous thin film	Physical adsorption	/	[112]
	Flower shaped nanostructure	Physical adsorption	0.012	[113]
Cholesterol	Nanospheres	Physical adsorption	0.5	[114]
	Nanorods	Electrostatic	0.03	[115]
	Nanorods	Electrostatic	1	[116]
	Nanorods	Electrostatic	1	[117]
	Nanobiocomposite film	Physical adsorption	3mg/dl	[119]
Urea	Nanofilm	Physical adsorption	13.5 mg/dl	[120]
	Nanorods	Electrostatic	0.4	[121]
	Nanowires	Physical adsorption	/	[122]