Design and Development of Biosensors for the Detection of Heavy Metal Toxicity

Table 4

Principle characteristics of enzyme biosensors for heavy metal detection.

Enzyme	Detection; working electrode; applied potential	Limit of detection	References
AChE	Amperometry; G/AChE; 0.80 V versus SCE	10^−10 M Hg^2+	[43]
ALP	Conductometry; Au/ALP-GA-BSA-glycerol;—	0.5 ppm Cd^2+, 2 ppm Zn^2+, 2 ppm Co^2+, 5 ppm Ni^2+, 40 ppm Pb^2+	[13]
ALP	Amperometry; SPE/ALP-chitosan; +0.6 versus Ag/AgCl	mg/L Hg^2+, Cd^2+, Ag^+, Zn^2+, Cu^2+	[51]
ALP	Fluorescence;—	10.1 𝜇M Ag^+	[12]
ALP	Chemiluminescence;—	0.36 ppb Zn^2+	[52]
HRP	Amperometry; GCE/MB-HRP-GdA	0.1 ng/mL HgCl2, 0.2 ng/mL Hg2(NO3)2	[7]
Gox	Amperometry; Pt/PA/Fc/GA/GOx; +0.7 V versus SCE	0.49 𝜇g/L Hg^2+	[48]
Gox	Amperometry; Pt/PPD/GOx; +0.7 V versus SCE	2.5 𝜇M Hg^2+, 0.05 𝜇M Ag^+, 5.0 𝜇M Cu^2+, 5.0 𝜇M Cd^2+, 12.0 𝜇M Fe^3+, 8.0 𝜇M Co^2+, 4.8 𝜇M Ni^2+, 48 𝜇M CrO4^2−	[20, 47]
Inv Gox	Amperometry; Pt/Inv-Gox-agarose-guar gum; +0.35 versus Ag/AgCl	5*10^−10 M Hg^2+, 3* 10^−8 M Pb^2+, 5* 10^−8 M Ag^+, 2.5* 10^−8 M Cd^2+	[49]
Inv Mu Gox	Amperometry; Pt/Inv-Mu-Gox-laponite; +0.6 versus Ag/AgCl	3 ppb Hg^2+	[50]
LDH LOD	Amperometry; Clark electrode (Pt cathode);−0.7 Vversus Ag/AgCl	1 𝜇M HgCl2, 10 𝜇M Cu^2+, 25 𝜇M Zn^2+	[22]
NR	Conductometry; Pt/NR–GA-BSA-metyl viologen/ Nafion	0.05 𝜇M Cu ^2+, 0.5 𝜇M Zn^2+, 0.1 𝜇M Cd^2+, 1 𝜇M Pb^2+	[45]
PQQ-GDH	Amperometry; G/PQQ-GDH-GA; +0.25 versus Ag/AgCl	15* 10^−5 M Cd^2+, 15* 10^−5 M Pb^2+	[15]
Ty	Amperometry; GCE/Ty-pPy;+0.4 versus Ag/AgCl	5 10^−7 M Cr^3+	[41]
Ty	Conductometry; Ty-GA-BSA/Pt;—	1 ppb Cu^2+	[40]
Urease	Amperometry; Pt/PVF/urease;+0.7 V versus SCE	7.4 𝜇M Hg^2+	[34]
Urease	Potentiometry; PVC-NH2/Au-NP/urease;—	0.05 𝜇M Hg^2+	[53]
Urease	Potentiometry;SPE (RuO2+urease+ graphite);—	—	[54]
Urease	Potentiometry; Ir/IrO2/Urease-PVC;—	0.02 𝜇M Hg^2+	[5]
Urease	Potentiometry; NH4^+ - ENFET;—	0.2 𝜇M Cu^2+, 0.1 𝜇M Hg^2+	[55]
Urease	Conductometry; SPE;-	0.005 mM Hg^2+, 0.02 mM Cu^2+, 0.1 mM Cd^2+, 0.9 mM Pb^2+	[35]
Urease/GLDH	Amperometry; C-Rh; +0.3 versus Ag/AgCl	7.2 𝜇g/L Hg^2+, 8.5 𝜇g/L Cu^2+, 0.3 mg/L Cd^2+, 0.2 mg/L Zn^2+	[56]

ALP = alkaline phosphatase; Au-NP = gold nanoparticles; BSA = bovine serum albumin; C-Rh = rhodinised carbon electrode; ENFET = enzyme field effect transistor; Fc = ferrocene; MB = methylene blue; GA = glutaraldehyde; GdA = glutaric dialdehyde; GCE= glassy carbon electrode; GLDH = glutamate dehydrogenase; Gox = glucose oxidase; Inv = invertase; Mu = mutarotase; NR = nitrate reductase; PA = polyaniline; PPD = poly(o-phenylenediamine); pPy = polypyrrole; PQQ-GDH = pyrroloquinoline quinine dependent glucose dehydrogenase; PVC = poly(vinyl chloride); PVC-NH₂ = ethylenediamine poly(vinyl chloride); PVF = poly(vinylferrocenium); SCE = saturated calomel electrode; SPE = screen-printed electrode; Ty = tyrosinase.