Table 2.
Electrochemical nucleic acid-based biosensing methods reported since 2017 for the determination of food allergens and adulterants.
| Electrode | Methodology | Target Allergen/Adulterant (Food) | Detection Technique | Linear Range | LOD | Sample | Steps */Assay Time | Ref. |
|---|---|---|---|---|---|---|---|---|
| Allergens | ||||||||
| SPCE | Sandwich hybridization assay involving biotinylated DNA Cp and Dp implemented on the surface of Strep-MBs and coupled to Express-PCR (100 bp-amplicon) | Cor a 9 (Hazelnut) | Amperometry (H2O2/HQ) | 0.0024–0.75 nM (synthetic target DNA) | 0.72 pM (synthetic target DNA) 20 pg gDNA extracted from hazelnut | hazelnut varieties and other species of similar families (pistachio, cashew, walnut and tangerine) | 1/15 min starting from bCp-Strep-MBs | [36] |
| SPCE | Indirect competitive approach between a biotinylated peptide (b-Pep) immobilized onto Strep-SPCE and gluten proteins for a defined concentration of biotinylated Gli4 aptamer further labeling with Strep-HRP | Gliadin (Gluten) | Chronoamperometry (H2O2/TMB) | 1–100 μg L−1 (four-parameter logistic equation) | 0.113 μg L−1 Gliadin (< >380 μg kg−1 gluten) | Food samples (Fixamyl, Rolled oats, Fit Snack) | 2/60 min starting from b-Pep-Strep-SPCE | [16] |
| SPCE | Sandwich hybridization assay involving a b-RNACp and a RNADp implemented on the surface of Strep-MBs and recognition of the RNA/DNA heterohybrids with AbRNA/DNA further conjugated with an HRP-secondary antibody | Sola l 7 (Tomato) | Amperometry (H2O2/HQ) | 0.8–50 pM (synthetic target) | 0.2 pM (synthetic target) | Tomato and corn (100 ng extracted gDNA) | 2/1.5 h starting from b-RNACp-Strep-MBs | [57] |
| AuNPs-modified Au-SPE | Direct aptasensing approach at AuNPs-Au-SPE modified with a SH-Aptamer | Lysozyme | CV ([Fe(CN)6]3-) | 1–10 μg mL−1 | 0.32 μg mL−1 | Wines | 1/1 h starting from SH-Aptamer-AuNPs-Au-SPE | [33] |
| SPCE | Indirect competitive approach between a biotinylated peptide (b-Pep) immobilized onto Strep-MBs and gluten proteins for a defined concentration of biotinylated Gli1 aptamer further labeling with Strep-HRP | Gliadin (Gluten) | Chronoamperometry (H2O2/TMB) | - | - | - | 2/60 min starting from b-Pep-Strep-MBs | [34] |
| Adulterants | ||||||||
| SPCE | Direct hybridization assay at b-RNACp-Strep-MBs and and recognition of the RNA/DNA heterohybrids with AbRNA/DNA further conjugated with ProtA-polyHRP40 | Specific fragment of horse mitochondrial DNA D-loop region (Meat) | Amperomety (H2O2/HQ) | 0.39–75 pM | 0.12 pM (synthetic target DNA) | Beef meat spiked with horse meat | 2/1 h 30 min starting from b-RNACp-Strep-MBs | [37] |
| Au disk(2-mm) | E-DNA based on a MB-modified thiolated DNA (Signal-off) | Melamine (Milk) | SWV (MB) | - | 150 μM(~19 ppm) in buffered solutions,20 μM (~2.5 ppm) in whole milk | Milk | Continuous, real-time mesurements in flowing samples | [35] |
AuNPs: gold nanoparticles; b: biotin; Cp: capture probe; Dp: detector probe; HQ: hydroquinone; HRP: horseradish peroxidase; LSV: linear square voltammetry; MB: methylene blue; MBs: magnetic beads; Pep: peptide; SPCE: screen-printed carbon electrodes; Strep: streptavidin; SWV: square wave voltammetry; TMB: 3,3′,5,5′-Tetramethylbenzidine. * Number of steps involved in the determination other than detection and sample preparation.