Table 1.

Highlights of nanosensors for pesticide detection

Nanosensor type	Used nanomaterial	Pesticide detected	Limit of detection	Method of nanosensor Formulation	Sensing mechanism	Observation	References
Fluorescent-nanosensor	3-aminopropyl-triethoxysilane coated Yb2O3	Imazapyr	0.2 ppm	Hydrothermal method	Quenching of fluorescence intensity for APTES coated Yb2O3 NPs with the increasing concentration of imazapyr	Among the lanthanide oxide based nanomaterials, ytterbium (III) oxide (Yb2O3) NPs owes unique optical and luminescence properties with excellent efficiency for real field conditions	[173]
Surface plasmon resonance (SPR) based affinity sensor	Atrazine imprinted nanoparticles	Atrazine	0.7134 ng/mL	Atrazine imprinted nanoparticles synthesis using emulsion polymerization method followed by their attachment on the gold surface of SPR	Increase in resonance frequency in proportion to the increment in atrazine concentration	The plastic antibody-based SPR nanosensor is an attractive recognition element for the detection of atrazine with high selectivity and sensitivity	[174]
Surface plasmon resonance based fiber–optic nanosensor	Tantalum(V) oxide nanoparticles	Fenitrothion	38 nM	Chemical synthesis of Ta2O5 nanoparticles embedded in reduced graphene oxide matrix followed by its adhesion on silver-coated fiber optic probe	Change in refractive index due to the interaction of fenitrothion with the silver film	The sensor is selective, repeatable and works at ambient temperature with a response time of 23 s	[175]
Fluorescence sensor	Copper (II) oxide and multiwall carbon nanotubes (MWCNTs)	Glyphosate	0.67 ppb	CuO/MWCNT were prepared by precipitating copper nitrate by the addition of aqueous NaOH solution	Inhibition of the catalytic activity of CuO/MWCNTs	A highly selective & promising approach for rapid screening of glyphosate	[176]
Electrochemical Luminescence sensor	Luminol-gold nanoparticles-L-cysteine-Cu(II) composites	Glyphosate	0.5 nM	Layer-by-layer assembly of graphene-gold nanoparticle composite and Lu-Au-Lcys-Cu(II) composite	Decrease in electrochemical luminescence intensity with a respective increase in the glyphosate concentration	The sensor worked on dual inhibition strategy with excellent detection performance, high sensitivity, desirable reproducibility, stability, and accuracy	[177]
Electrochemical sensor	CuO-TiO2 hybrid nanocomposites	Methyl parathion	1.21 ppb	CuO-TiO2 nanocomposites prepared by a facile liquid-control-precipitation method were decorated on the glass carbon electrode	Differential pulse voltammetry measurements assessed from decline in current density with increase in the methyl parathion concentration	A non-enzymatic sensor with good stability and excellent reproducibility	[103]
Electrochemical aptasensor	Chitosan-iron oxide nanocomposite	Malathion	0.001 ng/mL	Iron Oxide nanoparticles synthesized using chemical co-precipitation method were deposited on fluorine tin Oxide followed by the immobilization of aptamer onto the iron oxide doped-chitosan/FTO electrode using streptavidin	Decline in the Differential Pulse Voltammetry peak current of the aptaelectrode with a corresponding increase in malathion concentration due to the formation of more 3D-complex between aptamer with malathion	A very attractive alternative to quantify and monitor malathion due to its sensitivity, stability, short analysis time and cost-effectiveness	[110]
Electrochemical nanosensor	CuO nanoparticles decorated 3D graphene nanocomposite	Malathion	0.01 nM	Copper oxide nanoparticles electro-catalyst was prepared on 3D graphene synthesized using hydrothermal process	Decline in peak current with the increasing concentrations of malathion	Highly sensitive, reproducible and applicable in real field conditions	[109]
Optical nanosensor	Silver nanodendrites	Dimethoate	0.002 ppm	Ag nanodendrites fabricated by laser-assisted photochemical method were immobilized on the surface of microsphere end-shape optical fibre	Increase in the intensity of the surface-enhanced Raman spectroscopy (SERS) signal with a proportionate increase in dimethoate concentration	A direct, rapid, real-time and non-destructive method of detecting pesticide residue in the outdoor fields	[107]
Optical sensor	Upconverting nanoparticles (UCNPs) of the NaYF4:Yb, Er type	Metribuzin	6.8 × 10−8 M	Upconverting nanoparticles synthesized using the coprecipitation method of lanthanide metal-EDTA complexes were later used in the preparation of the sensor film by dissolving UCNPs in tetrahydrofuran along with the incorporation of NIR dye, PVC polymer, dioctyl phthalate	Metribuzin changes the color of sensor film from green to blue with a significant blue shift in the absorption peak	Highly sensitive sensor with unique luminescence properties of UCNPs and great recognition abilities within a very low detection limit	[108]