Table 1. Recent metal ion sensors developed using DNAzymes, the type of DNAzyme and the samples in which sensors were tested.

Detection Mode	Analyte		LOD		DNAzyme Name	Sample			Ref.
Fluorescence-B Detectionased
	UO22+		2.4 pM		39E DNAzyme	Mine and Pond water			[42]
	UO22+, Pb2+		0.6 nM, 3.9 nM		39E and 8-17 DNAzymes	Cellular			[51]
	Pb2+		1.7 nM		8-17 DNAzyme	River, Lake, and Waste water			[45]
	Pb2+		2 nM		GR-5 L-DNAzyme	River water + salt and buffer			[53]
	Hg2+		None Given		UV1C DNAzyme	Tap Water			[40]
	Cu2+		500 pM		CA3 variant DNAzyme	Tap			[39]
	Cu2+		1.6 nM		PsCu10 DNAzyme	Lake water			[44]
	Cd2+		1.6 nM		BN-Cd16 DNAzyme	Rice extract			[17]
	Ag+		24.9 nM		Ag10c DNAzyme	Lake water			[23]
	Cr3+		70 nM		Ce13d DNAzymes	Groundwater			[18]
	Zn2+		None Given		8-17 DNAzymes	Cellular			[58]
Electrochemiluminescent Detection
	Pb2+		6.4 pM		8-17 DNAzyme	Buffer			[59]
	Pb2+		∼50 pM		8-17 DNAzyme	Mineral, Drinking, and Snow water			[60]
	Cu2+		1 nM		CA3 variant DNAzyme	Human hair extract buffer			[61]
	Ag+		2 pM		HRP-mimicking DNAzyme	River water			[62]
Electrochemical Detection
	UO22+		2 pM		39E DNAzyme	River water		[63]
	UO22+		20 pM		39E DNAzyme	River water		[64]
	Pb2+		0.034 pM		8-17 DNAzyme	Tap and lake water		[65]
	Pb2+		0.005 nM		8-17 DNAzyme	Lake water		[66]
	Pb2+		37 pM		8-17 DNAzyme	Buffer		[67]
	Pb2+		43 pM		8-17 DNAzyme	Tap water (5%)		[68]
	Pb2+		0.25 nM		8-17cis DNAzyme	Lake water sample		[69]
	Pb2+		500 pM		HRP-mimicking DNAzyme	Buffer		[70]
	Hg2+		5.8 nM		HRP-mimicking DNAzyme	Rap and Waste water		[71]
	Cu2+		0.1 aM		CA3 variant DNAzyme	River water		[72]
Colorimetric Detection
	UO22+		37 nM		39E DNAzyme	Filtered (0.25 μM) Lake water		[73]
	Pb2+		12 pM		8-17 DNAzyme	Tap and River water, and Landfill leachate		[74]
	Pb2+		20 pM		8-17 DNAzyme	River water		[75]
	Ce3+		20 nM		Multiple DNAzymes	Lake water		[76]
Surface Enhanced Raman Scattering Detection
	UO22+		1 pM		39E DNAzyme	Sea, River, and Pond water		[77]
	Pb2+		8.9 pM		8-17 DNAzyme	Lake, Tap, and Industrial waste water		[78]