Table 4.

Current sensitive electrochemical biosensors using the RedOx intercalating agent.

MicroRNA	Intercalent Agent	Platform	Amplification of Signal Elements	Tech	Linear Range	LOD	Real-Samples Application	Ref
miRNA-155	OB	GCE/GO/GNR	-	DPV	2.0 fM–8.0 pM	0.6 fM	Spiked human plasma	[157]
miRNA-21	TB	GCE/AuNPs-Ppy	-	DPV	100 aM–1 nM	78 aM	Spiked human serum.	[138]
miRNA-196a	MB	AuE	DNA extension reaction	DPV	0.05 fM–50 pM	15 aM	Spiked plasma	[148]
miRNA-486-5p	Thinonine	GCE/FeCN/AuNPs	FeCN	DPV	1 fM–1000 pM	8.53 fM	Human lung A549 cells	[158]
miRNA-141	RuHex	AuE	HP-AuNPs	DPV	0–10 nM	25.1 aM	Human breast cancer cells MDA-MB-231	[150]
miRNA-21	RuHex	AuE	AuNPs enrichment by bridge DNA,	Chronocoulometry	0.1fM–0.1nM	68 aM	Serum samples from lung cancer patients	[159]
miRNA-21	RuHex	GCE/AuNPs@MoS2	AuNPs@MoS2	DPV	10 fM–1 nM	0.78 fM	Spiked human serum	[160]
miRNA-21	Molybdophosphate	AuE	HCR	SWV	1 fM–1 nM	0.78 fM	Spiked human serum	[161]
miRNA-21	CuNCs	AuE	HCR	DPSV	10 pM–0.1 fM	10 aM	Spiked blood sample	[162]
miRNA-21	Hemin	AuE	HCR	DPV	15 fM–250 pM	13.5 fM	Spiked human serum	[152]
miRNA-199 a	AgNPs	AuE	C-rich loop DNA templates	DPV	1.0 fM–0.1 nM	0.64 fM	Spiked human serum	[142]

Abbreviations: GCE, glassy carbon electrode; MB, methylene blue; DPV, differential pulse voltammetry; AuE, gold electrode; FeCN, iron-embedded nitrogen-rich carbon nanotubes; AuNPs, gold nanoparticles; A549 cells, adenocarcinoma cells; GO, graphene oxide; GNR, gold nanorods; Ppy, polypyrrole; RuHex, hexaammineruthenium III chloride; HP-AuNPs, hairpin-modified gold nanoparticles; MDA-MB-231: human breast cancer cells; HCR, hybridization chain reaction; SWV, square wave voltammetry; CuNCs, copper nanoclosters; DPSV, differential pulse stripping voltammetry; AgNPs, silver nanoparticles; C-rich loop DNA templates, cytosine-rich loop DNA templates; TB, toluidine blue; OB, oracet blue.