Table 3.

Examples of biosensors including 2D nanomaterials for the detection of marine toxins.

Analyte	Description/Immobilization Details	Analytical Performances	Selectivity	Application	Ref
Mycrocystin LR (MC-LR)	APT/Commercial graphene-modified screen-printed electrode; Detection by SWV using [Fe(CN)6]4–/3−	Range: 1.9 pM–1.0 nM; DL: 1.9 pM; Stability: 2.9% decrease in activity after 1 month at 4 °C; Incubation time with MC-LR: 45 min	Okadaic acid, microcystin-LA, and microcystin-YR not interfering	Spiked fish extract and spiked tap water	[107]
MC-LR	APT/BiOBr nanoflakes/n-doped graphene/ITO; Photoelectrochimical biosensor	Range: 1 pM–100 nM; DL: 3.3 × 102 pM; Incubation time with MC-LR: 30 min; Stability: no change in activity after 2 weeks at 4 °C	MC-LA, MC-YR not interfering	Spiked fish extract	[108]
Cylindrospermopsin	APT/Thionine–graphene; Detection by EIS using [Fe(CN)6] 4–/3−	Range: 0.39−78 ng mL−1 (1–200 nM); DL: 0.117 ng mL−1 (300 pM); Incubation time with CYN: 2 h; Stability: 88.2% and 74.7% of activity after 14 days and 30 days, respectively of storage in buffer at 4 °C	MC-LR, okadaic acid not interfering	Spiked lake water	[109]
Brevetoxin i	Ab-magnetic beads + BTX2-BSA-GGNR+ MCPE; Detection by SWV	Range: 1.0 pg mL−1–10 ng mL−1; DL: 1.0 pg mL−1; Incubation time with BTX2: 30 min	-Okadaic acid, MC-LR, Na+, K+, Ca2+, Mg2+, Sr2+, Cl−, SO4 2−, Br−, HCO3−, and F− not interfering. -BTX1, BTX3 interfere due to the cross-reactivity of the antibody for BTX2	Spiked mollusks extracts	[144]
Saxitoxin	Ab/Graphene nanosheets—lipid films; Detection by potentiometry.	Range: 1 × 10−9 M∓1 × 10−6 M; DL: 1 nM; Response time: less than 20 min	Mg2+, Ca2+, HC3−, SO42−, Cl−, NO3−, NH4+ not interfering	Lake water and shellfish samples; Spiked mussels, oysters, and mollusks	[145]
Okadaic Acid	Ab/GSPE + okadaic acid-ovalbumin conjugate; Detection by SWV using [Fe(CN)6] 4−/3−	Range: up to 5000 ng L−1; DL: 19 ng L−1; Stability: 98% of activity after 40 days at 4 °C	Microcystin-LA not interfering	Spiked mussel extract	[146]
MC-LR	Ab-GO-IL -Au NP/GCE; Detection by DPV using [Fe(CN)6]4−/3−	Range: 0.1–1000 ng mL−1; DL: 0.1 ng mL−1; Incubation time with MC-LR: 50 min; Stability: 90.58% after 30 days in buffer at 4 °C	MC-LA, MC-RR, and MC-YR, as Na+, Ca 2+, K+,Cl−, and CO3 2− not interfering	Spiked river water	[147]
MC-LR	APT/AgI-NG/ITO; Photoelectrochemical aptasensor,	Range: 0.05 pM–5 nM; DL: 0.017 pM; Incubation time with MC-LR: 20 min; Stability: 94.5% of activity after 2 weeks at 4 °C	MC-LA and MC-YR are not interfering	Spiked fish	[148]
MC-LR	Ab/oxidized CVD graphene; Detection by EIS	Range: 0.005–10 μg L−1; DL: 2.3 ng L−1; Stability: 92.5% and 83.6% of activity after 1 and 2 weeks of storage at 4 °C.	Environmental water samples with TOC 0.53–8.99 mgL−1, total dissolved solid 118–170 mgL−1, sodium, (2.62–7.46 mgL−1), magnesium (4.9–14.67 mgL−1), aluminium (0.25–0.47 mgL−1), potassium (0.02–3.56 mgL−1), calcium (2.29–2.93 mgL−1), manganese (0.49–14.32 µgL−1), iron (0.86–174.2 µgL−1), copper (1.19–7.99 µgL−1) are not interfering	Spiked tap water, pond water, and lake water	[114]
MC-LR	APT/GO-modified printed electrode; (aptamer adsorbed or covalently immobilized; Detection by SWV using [Fe(CN)6]4−/3−.	Apt/Phys−300 μm; Range: 0.1 nM–1.0 μM DL: 0.038 nM; Apt/Phys−0.22 μm; Range: 0.1 nM–1.0 μM; DL: 0.088 nM; Apt/Cov−300 μm; Range: 1 nM−1.0 μM; DL:0.25 nM; Apt/Cov−0.22 μm: Range: 1 nM−1.0 μM; DL: 0.018 nM	Okadaic acid, MC-LA not interfering	N/A	[149]
Microcystin-L vccccR	MC-LR/AuNP@MoS2-TiONB/GCE + biotin-cDNA + Avidin-HRP; Detection by DPV	Range: 0.005–30 nM; DL: 0.002 nM; Incubation time: 120 min (60 min with the mixture of cDNA and MC-LR and 60 min with avidin -HRP; Stability: 90% activity after 10 days at 4 °C.	MC-LA, MC-YR, atrazine, and trichlorfon are not interfering	Spiked tap water, reservoir water and river water	[21]
MC-LR	Ab1/AuNR/MoS2/+HRP-Ab2; Detection by DPV	Range: 0.01–20 μg L−1; DL: 5 ng L−1; Incubation time with MC-LR: 1 h at 37 °C. and incubation with HRP-anti-MC-LR: 1 h at 37 °C; Stability: 99.46% and 95.62% after 1 week and 4 weeks of storage at 4 °C, respectively.	MC-RR, Okadaic acid, starch, ascorbic acid, Na+, NH4+, Ca2+, Cl−, SO42−, and CO32− not interfering	Spiked: lake water, tap water, and drinking water	[150]
MC-LR	Ab/BSA-stabilized Au nanoclusters/MoS2/Au electrode: +Au@Pt core-shell nanoparticles Detection by DPV	Range: 1.0 ngL−1–1.0 mgL−1; DL: 0.3 ngL−1; Incubation time with MC-LR: 1 h at 37 °C. and incubation with Au@Pt: 1 h at 37 °C; Stability: 98% and 92% of initial activity after 1 week and 4 weeks storage at 4 °C	MC-RR, MC-LA, dopamine, uric acid, ascorbic acid, Al3+, Ca2+, Mg2+, Na+, K+, NH4+, SO42−, CO32−, NO3− not interfering	Spiked water samples Recoveries: 99.6–101.3%	[151]
Okadaic acid	APT/phosphorene-gold NP/SPCE Detection by DPV using [Fe(CN)6]3−/4−	Range: 10 nM−250 nM; DL: 8 pM		Spiked mussel extract	[152]