Table 2.

Summary of paper-based biosensors used in electrochemical immunosensor and aptasensor detection.

S.NO	Target	Material	Detection Methods	Linear Range	LOD	References
Electrochemical immunosensor
1.	CA 15.3	Ag-RGO/CysA-Au NPs	ChA	15–125 U/mL	15 U/mL	[51]
2.	CA 125	rGO/Thi/AuNPs	CV, DPV	0.1~200 U/mL	0.01 U/mL	[36]
3.	Spike protein of SARS-CoV-2	CNC-SPGE	DPV	0.1 pg/mL to 500 ng/mL	2.0 fg/mL	[52]
4.	Human IFN-γ	PANI/G	EIS	5–1000 pg/mL	3.4  pg/mL	[53]
5.	Glycoprotein	SiO2@Au/dsDNA/CeO2	DPV	1 pg/mL–1000 ng/mL	0.87 pg/mL	[54]
6.	Alpha-fetoprotein	Ni-Co MOF	DPV	1–200 ng/mL	0.3 ng/mL	[55]
7.	Cardiac troponin I	MXene	EIS	5–100 ng/mL	0.58 ng/mL	[56]
8.	5-hydroxy-l-tryptophan	Graphene nanoribbons	SWV	25–1000 μmol/L	7.6 μmol/L	[57]
Aptasensor
9.	Carcinoembryonic antigen	NG-THI-AuNPs-PB-PEDOT	DPV	0.01–500 ng/mL	2 pg/mL	[58]
10.	17β-Estradiol	Amino redox graphene/thionine/streptavidin-modified gold nanoparticles/chitosan	DPV	10 pg/mL to 100 ng/mL	10 pg/mL	[59]
11.	Kanamycin	Graphene	Potentiometry	0.05–30 pM	0.05 pM	[60]
12.	Breast cancer cells (MCF-7)	Paper-based aptasensor and gold nanoparticles	CV, DPV and EIS	20 to 1 × 106 cells mL−1	7 cells mL−1	[61]
13.	Programmed death-ligand 1	Amino carbon nanotubes/methylene blue	CV, DPV	10 pg/mL–2.5 ng/mL	10 pg/mL	[62]
14.	Oxytetracycline	Multiwall carbon nanotubes, gold nanoparticles, reduced graphene oxide and chitosan	CV, DPV and EIS	1.00–540 nM	10 nM	[63]
15.	SARS-CoV-2	Carbon nanofibers and gold nanoparticles	EIS	0.01–64 nM	7.0 pM	[64]