Table 2.

Overview of recent electrochemical biosensors for pathogenic bacteria determination.

Electrode	(Bio)Sensor Format	Electrochemical Technique	Analyte/Sample	L.R.	LOD	References
GCE	Electrochemical immunosensor based on high-density gold nanoparticles (AuNPs), dispersed in chitosan (CHI) hydrogel, and modified glassy carbon electrode (GCE)	DPV	Salmonella/milk, water	10–105 CFU mL−1	5 CFU mL−1	[100]
SPCEs	Label-free impedimetric aptasensor assembled by grafting a diazonium-supporting layer onto screen-printed carbon electrodes (SPCEs), followed by chemical immobilization of aminated-aptamer	EIS	Salmonella/apple juice	10–108 CFU mL−1	6 CFU mL−1	[101]
AuE	Label-free impedimetric aptasensor based on combining poly-[pyrrole-co-3-carboxyl-pyrrole] copolymer and the Salmonella aptamer	EIS	Salmonella/apple juice	102–108 CFU mL−1	3 CFU mL−1	[102]
GCE	Electrochemical aptasensor developed using electrochemically reduced graphene-oxide–chitosan (rGO–CHI) composite deposited onto GCE	DPV	Salmonella/chicken	10–106 CFU mL−1	10 CFU mL−1	[103]
AuE	Electrochemical aptasensor developed by combining target-induced aptamer displacement on gold nanoparticles (AuNPs) deposited onto Au electrode with rolling circle amplification (RCA)	DPV	Salmonella/milk, mineral water	20–207 CFU mL−1	16 CFU mL−1	[104]
GF-GCE	Electrochemical immunosensor based on anti- Salmonella antibody immobilized on the surface of the graphite felt electrode	OSWV	Salmonella/no real samples	-	105 E. coli cells mL−1	[105]
BiSPCE	Immunosensor where bacterial cells were separated immunomagnetically and reacted with conjugate; labeled with an electrochemical indicator, including hyperbranched dendron molecules and heavy metal-derived quantum dots (CdTe QDs). Square-wave anodic stripping voltammetry (SWASV) employing screen-printed carbon electrodes with in situ formed Bi(III) film (BiSPCE) was used for the detection and quantification of metal ions released from the QDs and correlated with the bacterium amount	SWASV	Salmonella/milk	-	4 CFU mL−1	[106]
AuIME	Electrochemical aptasensor using aptamer-coated gold-interdigitated microelectrode (IAuE) for target capture and impedance measurement, and antibody-modified nickel nanowires (NiNWs) for target separation and impedance amplification	EIS	Salmonella/chicken	102–106 CFU mL−1	80 CFU mL−1	[107]
AuIME	Immunosensor using multiple magnetic nanobead (MNB) nets in a ring channel for continuous-flow separation of target bacteria from the sample volume, manganese dioxide nanoflowers (MnO2 NFs) for efficient amplification of the biological signal, and an interdigitated microelectrode to measure impedance change	EIS	Salmonella/chicken	30–30 × 105 CFU mL−1	19 CFU mL−1	[108]
AuIME	Impedimetric immunosensor using rotary magnetic separation and cascade reaction	EIS	Salmonella/chicken	10–106 CFU mL−1	10 CFU mL−1	[109]
AuE	Electrochemical genosensor based on the immobilization of complementary DNA on the gold electrode surface, which hybridizes with a pathogen-specific fragment gene to make a sandwich structure	DPV	E. coli/beef	-	1.97 × 10−14 M	[113]
Magnetic-graphite epoxy composite (m-GEC) electrode (m-GECE)	Electrochemical magneto-genosensor based on the detection of the tagged amplified DNA obtained by single-tagging PCR with a set of pathogen-specific primers, followed by electrochemical magneto-genosensing on silica magnetic particles	Amperometry	E. coli/no real samples	0.03–3 ng mL−1	0.05 ng mL−1	[114]
AuE	Label-free impedimetric immunosensor using reduced graphene wrapped copper (II)-assisted cysteine hierarchical structure (rGO–CysCu) as the sensing layer	EIS	E. coli/water, fruit juice, milk	10–108 CFU mL−1	3.8 CFU mL−1	[115]
GCE	ECL aptasensor based on AgBr nanoparticles (NPs) anchored on 3D nitrogen-doped graphene hydrogel (3DNGH) nanocomposites for immobilizing luminol and enhancing its ECL behavior	ECL	E. coli/meal samples	0.5–500 CFU mL−1	0.17 CFU mL−1	[116]
SPCEs	Label-free impedimetric aptasensor using 3D hierarchical nanostructured bridged rebar graphene (BRG) for modifying SPCES	EIS	E. coli/water, juice, and milk.	102–106 CFU mL−1	10 CFU mL−1	[117]
PGE	Electrochemical immunosensor based on the PPy/AuNP/MWCNT/CHI hybrid nanocomposite modified pencil graphite electrode (PGE)	Amperometry	E. coli/no real samples	30–306 CFU mL−1	30 CFU mL−1	[118]
SPCEs	Electrochemical immunoassay using silica-coated Fe3O4 magnetic nanoparticles (Fe3O4@SiO2) and Au@Pt nanoparticles loaded on neutral red (NR) functionalized graphene to form composite complex rGO–NR–Au@Pt	CV	E. coli/pork and milk	4.0 × 103–4.0 × 108 CFU mL−1	4.0 × 102 CFU mL−1	[119]
GF-GCE	Electrochemical immunosensor based on anti- Escherichia coli antibody immobilized on the surface of the graphite felt electrode	OSWV	E. coli/beef	-	400 cells mL−1	[120]
AuIME	Electrochemical biosensor based on hybridization chain reaction (HCR)	MSPQC	S. aureus/milk and human serum	50–107 CFU mL−1	50 CFU mL−1	[122]
AuE	Electrochemical biosensor based on a triple-helix molecular switch, which can control the switching of electrochemical signals	DPV	S. aureus/water and honey	30–30 × 108 CFU mL−1	8 CFU mL−1	[123]
AuE	Label-free impedimetric immunosensor based on bacteria-imprinted conductive poly(3-thiopheneacetic acid) (BICP) film	EIS	S. aureus/milk	10–10 × 108 CFU mL−1	2 CFU mL−1	[125]
AuE	Dual signal amplification electrochemical biosensor based on a DNA walker and DNA nanoflowers	DPV	S. aureus/water and honey	60–60 × 107 CFU mL−1	9 CFU mL−1	[126]
SPCNF/AuNPsE	plcA-based electrochemical DNA biosensor using screen-printed CNF/AuNPs electrode	CV	L. monocytogenes/milk	0–0.234 ng/6 μL	82 fg/6 μL	[136]
Pt-IME	Aptasensor using platinum interdigitated microelectrodes (Pt-IME) biofunctionalized with Listeria-specific aptamer and a smartphone-based signal acquisition system	EIS	L. monocytogenes/vegetable broth, hydroponic media	102–106 CFU mL−1	23 CFU mL−1	[137]
SPCEs	Electrochemical immunosensor using a disposable screen-printed electrode as transducer surface and monoclonal and polyclonal antibodies specifically recognizing Listeria monocytogenes p60 protein used as the sandwich immuno-pair	CV	L. monocytogenes/milk	5–150 ng mL−1	1.5 ng mL−1	[138]
Disposable electrical printed (DEP) microarray electrode s	Electrochemical biosensor assembled by selectively functionalizing the array electrodes with bacteria-specific peptides	SWV	L. monocytogenes/no real samples	10–107 CFU mL−1	9 CFU mL−1	[139]

Abbreviations: AuE: gold electrode; AuNPs: gold nanoparticles; AuSPE: gold screen-printed electrode; Au-IME: gold interdigitated microelectrodes; CA: chronoamperometry; CF: carbon felt; CNF: carbon nanofibers; CV: cyclic voltammetry; DEP: Disposable electrical printed microarray electrode; DPV: differential pulse voltammetry; EIS: electrochemical impedance spectroscopy; GCE: glassy carbon electrode; GF: graphite felt; GO: graphene oxide; ITO: indium–tin-oxide electrode; MBs: magnetic beads; m-GEC: magnetic graphite-epoxy composite; MWCNTs: multi-walled carbon nanotubes; OSWV: Osteryoung square-wave voltammetry; PPY: polypyrrole; QDs: quantum dots; Pt-IME: platinum interdigitated microelectrodes; SPCE: screen-printed carbon electrode; SWV: square-wave voltammetry; SWASV: square-wave anodic stripping voltammetry.