Table 1.
Electrochemical affinity biosensors reported over the last five years involving the use of GQDs or CDs.
| Electrode | Bioassay format | Nanomaterial(Role) | Target | Technique | Linear range | LOD | Assay time | Sample | Reference |
|---|---|---|---|---|---|---|---|---|---|
| GCE | Direct immunosensor | AgNPs/thiol-GQDs (electrode modifiers) | HCV | DPV (riboflavin) | 0.05 pg mL−1–60 ng mL−1 | 3 fg mL−1 | 30 min + AgNPs (2 h) + Thiol-GQDs (54 h) + CAb/AgNPs/thiol-GQD/GCE (>3 h) | Spiked human serum | [56] |
| Au-SPE | Direct immunosensor | PAMAM/GQDs (electrode modifiers) |
cTnI | CV, DPV (Fe(CN)63-) | 1.0 10−6–1.0 × 10−3 | 20 fg mL−1 (CV) 25 fg mL−1 (DPV) |
10 min once prepared the Au/GQD/PAMAM/CAb (30 h) | Human blood serum | [10] |
| SPCE | Direct immunosensor | GQDs (electrode modifiers) |
cMyo | DPV (Fe3+ group of the cMyo) | 0.01–100 ng mL−1 | 0.01 ng mL−1 | 10 min once prepared the CAb/GQDs/SPCE (1 h 10 min) | Spiked human serum | [40] |
| SPCE | Direct immunosensor | GQDs grafted with 2-ABA (electrode modifiers) |
Parathion | EIS ([Fe(CN)6]3-/4-) |
0.01–106 ng L−1 | 46 pg L−1 | 5–30 min once prepared the CAb/GQD/SPCE (~3.5 h) | — | [9] |
| SPCE | Direct immunosensor | GQDs grafted with 2-ABA (electrode modifiers) |
AXL | DPV ([Fe(CN)6]3-/4-) |
1.7−1000 pg mL−1 | 0.5 pg mL−1 | 90 min once prepared the CAb/GQD/SPCE (~4 h) | Human serum | [43] |
| GCE | Direct immunosensor | PtPd/N-GQDs@Au (electrode modifiers) | CEA | Amperometry (H2O2) | 5 fg mL−1–50 ng mL−1 | 2 fg mL−1 | 1 h + CAb/PtPd/N-GQDs@Au/GCE (2 h) + PtPd/N-GQDs@Au (~47 h) | Spiked human serum | [49] |
| GCE | Sandwich immunosensor | Fe3O4@Ag/GQDs (electrode modifiers) and DAb-AuNPs as labels |
CFP-10 | DPV (Au3+) | 0.005–500 mg mL−1 | 0.33 ng mL−1 | 2 h once prepared the CAb/Fe3O4@Ag/GQD/GCE (~13 h) | Spiked human urine | [57] |
| SPCE | Sandwich immunosensor | MWCNTs/GQDs (nanocarriers of DAb+HRP) |
IL-13sRα2 | Amperometry (H2O2/HQ) | 2.7–100 ng mL−1 | 0.8 ng mL−1 | 1 h 45 min + BCAb-Strep/p-ABA/SPCEs (3 h 15 min) + MWCNTs/GQDs-HRP-DAb (~30.5 h) | Raw cellular lysates and extracts of paraffin-embedded tissues from CRC patients | [47] |
| SPdCE | Sandwich immunosensor | MWCNTs/GQDs (nanocarriers of DAb+HRP) |
13sRα2 + CDH-17 | Amperometry (H2O2/HQ) | 4.92–100 ng mL−1 (IL-13sRα2) 0.11–10 ng mL−1 (CDH-17) |
1.44 ng mL−1 (IL-13sRα2) and 0.03 ng mL−1 (CDH-17) |
1 h 45 min + BCAb-Strep/p-ABA/SPCEs (3 h 15 min) + MWCNTs/GQDs-HRP-DAb (~30.5 h) | Raw cellular lysates and extracts of paraffin-embedded tissues from CRC patients | [48] |
| GCE | Sandwich hybridization sensor | ZnFe2O4/GQDs (Trace label + nanocarrier of Dp) | Target DNA (S2) | DPV (H2O2/TH) | 10−16–5 × 10−9M | 6.2 × 10−17 M | 160 min + MCH/S1/Pd/GS/GCE (110 min) ZnFe2O4/GQDs-S3 (11 h) | Spiked human serum | [45] |
| Au disk electrode (2-mm φ) | Sandwich hybridization sensor | GQDs (platform for HRP immobilization) | miRNA-155 | Chronoamperometry (H2O2/TMB) | 1 fM–100 pM | 0.14 fM | 4 h once prepared the MCH/SHCp/Au (~13 h) | Spiked human serum (1/10 diluted) | [41] |
| GCE | Direct aptasensing strategy | AgNPs/thiol-GQDs (electrode modifiers) | TNT | DPV (RU) | 0.001–0.300 pM | 0.33 fM | 35 min + AgNPs (2 h) + Thiol-GQDs (54 h) + Ap/AgNPs/thiol-GQD/GCE (>16 h) | Spiked soil and water samples | [59] |
| Au-SPE | Direct hybridization | CDs (electrode modifiers) | Target DNAs | DPV (safranine) | 0.001–20 μM | 0.16 nM | 1 h + CDs (~3 days) + Cp/CDs/Au-SPEs (~2 days) | DNA isolated from peripheral blood leukocytes from cystic fibrosis patients | [1] |
| GCE | Direct hybridization | GQDs (electrode modifiers) | Target HBV-DNA | DPV (K3[Fe(CN)6]) | 10–500 nM | 1 nM | 30 min + Cp/GQDs/GCE (12.5 h) + GQDs (50 min) | — | [39] |
| ITO | Direct hybridization | CM/GQDs (electrode modifiers) | APOe4 DNA | DPV (CM) | 20–400 pg mL−1 | 0.48 pg mL−1 | — + Cp/CM/GQDs/ITO (>30 min) + GQDs (20 min) | 100-fold diluted human blood plasma pre-treated with ammonium sulfate | [58] |
p-ABA: p-aminobezoic acid; AXL: receptor tyrosine kinase; CAb: capture antibody; CEA: carcinogenic embryonic antigen; CM: curcumin; Cp: capture probe; CRC: colorectal cancer; CV: cyclic voltammetry; DAb: detector antibody; Dp: detector probe; DPV: differential pulse voltammetry; EIS: electrochemical impedance spectroscopy; GCE: glassy carbon electrode; HCV: hepatitis C virus core antigen; HBV: hepatitis B virus; HQ: hydroquinone; ITO: indium-tin oxide; N-GQDs: nitrogen-doped graphene quantum dots; PAMAM: poly(amidoamine); PtPd/N-GQDs@Au: nanocomposites of N-GQDs, PtPd bimetallic nanoparticles and Au nanoparticles; CFP-10: culture filtrate protein; GS: graphene sheet; MCH: mercaptohexanol; RU: rutin; SPCE: screen-printed carbon electrode; SPdCE: screen-printed dual carbon electrode; Strep: streptavidin; TH: thionine; TMB: 3,3′,5,5′-tetramethylbenzidine; TNT: 2,4,6-Trinitrotoluen.