Table 3.

Overview of reported electrochemical biosensor platforms for SARS-CoV-2 diagnosis.

Electrochemical Method	Target Biomarker	Linear Range	LOD	Biological Sample	Ref.
DPV measurement	S1 spike protein	5.0–500 ng/mL	2.9 ng/mL	Human serum	[42]
Paper based electrochemical measurement	RNA of the N gene	585.4–5.854 × 107 copies/μL	6.9 copies/μL	Nasopharyngeal swab	[43]
DPV measurement	Spike protein	0.04–10 μg/mL	19 ng/mL	Untreated saliva	[44]
	Nucleocapsid protein	0.01–0.6 μg/mL	8.0 ng/mL
DPV measurement	ORF1ab	10−2 fM-1.0 pM	200 copies/mL	Throat swab, Urine, Feces, Plasma, Whole blood, Saliva	[45]
DPV measurement	Nucleocapsid protein	0.22–333 fM	27 fM	Nasopharyngeal swab	[46]
EIS measurement	S protein	1.0 fM-1.0 nM	2.8 fM	Fetal bovine Serum, Rabbit Serum	[47]
	RBD		16.9 fM
SWV measurement	SP-RBD	1.0–1000 ng/mL	0.11 ng/mL	Human sera	[48]
SWV measurement	SARS-CoV-2 spike antibody	0.1–1000 ag/mL	0.01 ag/mL	Pretreated saliva and oropharyngeal swab	[49]
DPV measurement	MNP-S1/anti-S1 Ab	2.5–200 ng/mL	0.93 ng/mL	Nasopharyngeal swab (original, alpha, beta, and delta variants)	This work
	MNP-S1/Ab cocktail	1.0–200 ng/mL	0.53 ng/mL
	MNP-S2/anti-S2 Ab	1.0–200 ng/mL	0.99 ng/mL
	MNP-S2/Ab cocktail	2.5–100 ng/mL	0.75 ng/mL

AuNP: Gold nanoparticle, Cys: Cysteamine, DPV: Differential pulse voltammetry, EIS: Electrochemical impedance spectroscopy, FET: Field-effect transistor, LSG: Laser-scribed graphene, MNP: Magnetic nanoparticles, ORF: Open reading frame, PBASE: 1-pyrenebutyric acid N-hydroxysuccinimide ester, RBD: Receptor binding domain, SP-RBD: Spike protein receptor-binding domain, SWV: Square-wave voltammetry.