Table 1.
Representative electrochemical (bio)sensors exhibiting remarkable sensing attributes beyond sensitivity and selectivity.
| Electrode | Sensor Fundamentals | Transduction Technique | Attribute (used Approach) | Additional Features | Molecular Target Tested | L.R./LOD | Sample | Ref. |
|---|---|---|---|---|---|---|---|---|
| 16× Au electrode arrays prepared by photolithography |
Sandwich hybridization assay at arrays modified with SHCP/HDT+MCH | Chrono-amperometry (TMB/H2O2) | Antibiofouling (thiolated ternary monolayer) |
— | Synthetic target DNA (characteristic region of E. coli 16S rRNA) | LOD: 7 pM and 17 pM in spiked undiluted human serum and urine |
Raw undiluted human serum and urine | [20] |
| Au/SPEs | Sandwich hybridization assay at arrays modified with SHCP/HDT+MCH | Chrono-amperometry (TMB/H2O2) | Antibiofouling (thiolated ternary monolayer) |
— | Synthetic target DNA and E. coli 16S rRNA | LOD: 25 pM and 100 pM in spiked undiluted human serum and urine and 16S rRNA E. coli corresponding to 3000 CFU mL−1 in raw cell lysate samples |
Untreated raw serum, urine, and crude bacterial lysate solutions | [21] |
| AuE | E-AB: Aptamer dually modified with a thiol and a redox reporter + PC-terminated SAM | SWV (MB) | Antibiofouling (PC-terminated SAM) | Continuous operation label-free |
Kanamycin, doxorubicin | — | Flowing whole blood, both in vitro and in vivo (sensors placed in the jugular veins of live rats) | [12] |
| GOx-PB-graphite SPEs | Electrode modified with Eudragit® L100 |
CV ([Fe(CN)6]4−/3−) and Chrono-amperometry (PB/H2O2) |
Antibiofouling (pH-sensitive transient polymer coating) | Continuous operation | Glucose | — | Raw undiluted blood and saliva | [22] |
| Edible carbon paste GOx biosensors | Electrodes coated with Eudragit® E PO (pH < 5.0) or Eudragit® L100 (pH > 6.0) | Chrono-amperometry (PB/H2O2) |
Antibiofouling (pH-sensitive transient polymer coating) | Continuous operation Biocatalytic activity preservation at media with denaturing pH values |
Glucose | L.R.: 2−10 mM | GI fluids | [23] |
| PEDOT-citrate film-modified GCE | Covalent immobilization using EDC/NHS chemistry of a peptide with anchoring, antifouling, and recognizing capabilities onto GCE/PEDOT-citrate | DPV ([Fe(CN)6]4−/3−) |
Antibiofouling (multifunctional peptide) | — | APN, HepG2 cells |
L.R.: 1 ng mL−1−15 μg mL−1 (APN) and 50–5 × 105 cells mL−1 (HepG2 cells) LOD: 0.4 ng mL−1 (APN) and 20 cells mL−1 (HepG2 cells) |
Human urine | [24] |
| Au disk | E-DNA: DNA probe dually modified with a thiol and a redox reporter + MCH SAM | SWV (MB) | Continuous and real-time operation (Folded-biosensor) |
Reagentless and single-step | Melamine | LOD: 150 μM (∼19 ppm) in buffered solutions and 20 μM (∼2.5 ppm) in whole milk |
Flowing undiluted whole milk | [6] |
| Au | E-DNA: TDNs with two functional DNA/aptamer strands, one of them modified with MB |
SWV (MB) | Continuous and real-time operation (Folded-biosensor) |
Reagentless and single-step Antibiofouling Reusability |
Target DNA, ATP | LOD: 300 fM (target DNA), 5 nM (ATP) |
Flowing whole blood | [8] |
| AuE | E-DNA: nucleic acid “scaffold” attached on one end to an electrode and presenting both a redox reporter and a specific epitope on the other | SWV (MB) | Reagentless and single-step (Folded-biosensor) |
— | Three types of HIV-diagnostic antibodies | — | Human serum | [25] |
| Microfabricated Au onto MECAS chip | E-AB: Aptamer dually modified with a thiol and a redox reporter + MCH SAM | ACV (MB) | Continuous and real-time operation (Folded-biosensor) | Reagentless and single-step Reusability | Cocaine | — | Flowing undiluted blood serum | [9] |
| 100 nm Au layer sputtered on glass slides | E-AB: Hairpin structure aptamer dually modified with a thiol and a redox reporter (MB or AQ) + MCH SAM | SWV (MB, AQ) | Continuous operation (Folded-biosensor) |
Antibiofouling Reagentless and single-step | IFN-γ + TNF-α | LOD: 6.35 ng mL−1 (IFN-γ), 5.46 ng mL−1 (TNF-α) | Integrated into microfluidic devices to dynamically monitoring of cytokine release from immune cells (2.5 h) | [26] |
| Au wire | E-AB: Aptamer dually modified with a thiol and a redox reporter + MCH SAM | SWV (MB) | Continuous and real-time and in vivo operation (Folded-biosensor) | Reagentless and single-step | Doxorubicin, Kanamycin, Gentamycin, and Tobramycin | — | Bloodstream awake, ambulatory rats | [10] |
| Au disk, Au-plated SPCEs | E-PB: Peptide dually modified with a thiol and a redox reporter + MCH SAM | ACV, CV (MB) | Real-time operation (Folded-biosensor) |
Reagentless and single-step | Pb2+ | LOD: 5 μM (ACV) | Diluted tap water, saliva, and urine samples |
[27] |
| Au disk | E-ION: T-rich ssDNA dually modified with thiol and redox reporter + Hg2+ + MCH SAM | ACV (MB) | Real-time operation (Folded-biosensor) |
Reagentless and single-step Reusable |
GSH (displaces Hg2+ by chelation) | LOD: 5 nM | 50% synthetic human saliva | [28] |
| AuE | E-AB: Aptamer dually modified with a thiol and a redox reporter + MCH SAM | SWV (MB) | Calibration-free (“dual-frequency”) | Continuous and real-time operation Reagentless and single-step |
Cocaine, doxorubicin | — | Continuous measurement in flowing, undiluted whole blood |
[7] |
| Au-SPE | E-AB: Aptamer dually modified with a thiol and a redox reporter + MCH | SWV (MB) | Calibration-free (“dual-frequency”) |
Reagentless and single-step | Phenylalanine | L.R.: 90 nM−7 μM | Whole blood (diluted 1000-fold to match the sensor’s dynamic range) |
[3] |
| AuE | E-AB: Aptamer modified with a thiol and two different redox reporters + PC-terminated SAM | SWV (MB and AQ) | Calibration-free, (“dual reporter”) and in vivo operation | Continuous operation Antibiofouling Reagentless and single-step |
Cocaine, ATP, kanamycin | — | Flowing whole blood, both in vitro and in vivo (sensors placed in the jugular veins of live rats) | [2] |
Abbreviations: ACV: alternating current voltammetry; APN: aminopeptidase N; AQ: anthraquinone; ATP: anti-adenosine triphosphate; CFU: colony forming unit; CV: cyclic voltammetry; DPV: differential pulse voltammetry; E-AB: electrochemical aptamer-based; E. coli: Escherichia coli; EDC: carbodiimide; E-DNA: electrochemical DNA-based biosensor; E-ION: electrochemical for ion determination; E-PB: electrochemical peptide-based biosensor; GCE: glassy carbon electrode; GI: gastrointestinal fluids; GOx: glucose oxidase; GSH: glutathione; HDT: 1,6-hexanedithiol; HIV: Human Immunodeficiency Virus; INF-γ: interferon-γ; LOD: limit of detection; L.R.: linear range; MB: methylene blue; MCH: 6-mercapto-1-hexanol; MECAS: Microfluidic Electrochemical Aptamer-based Sensor; NHS: succinimide; PB: Prussian Blue; PC: phosphatidylcholine; PEDOT: poly (3,4-ethylenedioxythiophene); SAM: self-assembled monolayer; SHCP: thiolated capture probe; SPCEs: screen-printed carbon electrodes; SPEs: screen-printed electrodes; SWV: square wave voltammetry; T: thymine; TDNs: tetrahedral DNA nanostructures; TMB: tetramethylbenzidine; TNF-α: tumor necrosis factor-α.