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. 2018 Sep 17;10(5):1415–1426. doi: 10.1007/s12551-018-0457-9

Sensitivity limits of biosensors used for the detection of metals in drinking water

Vangelis George Kanellis 1,✉
PMCID: PMC6233349  PMID: 30225681

Abstract

Even when present in very low concentrations, certain metal ions can have significant health impacts depending on their concentration when present in drinking water. In an effort to detect and identify trace amounts of such metals, environmental monitoring has created a demand for new and improved methods that have ever-increasing sensitivities and selectivity. This paper reviews the sensitivities of over 100 recently published biosensors using various analytical techniques such as fluorescence, voltammetry, inductively coupled plasma techniques, spectrophotometry and visual colorimetric detection that display selectivity for copper, cadmium, lead, mercury and/or aluminium in aqueous solutions.

Keywords: Heavy metals, Biosensors, Sensitivity, Water, Toxicity, Detection limits

Introduction

Toxicity is typically measured by the amount of harm or ill health caused by exposure to toxicants. In general, there is an inverse relationship between the environmental abundance of metals and their toxicity (Lithner 1989). Some metals bioaccumulate after consumption of contaminated drinking water and/or seafood with varying degrees of toxicity (Gruber 1989). Various human activities contribute to the pollution of ground, drinking and wastewater with toxic metals (Chowdhury et al. 2016).

Previous biosensors have relied on bioassays using animal models such as Salmo gairdneri fish (Lanno et al. 1985), cladocerans (Ceriodaphnia dubia) (Hyne et al. 2005) or Daphnia magna (Bang et al. 2011) and Vibrio fischeri (commercialised by Microtox®). The widespread industrial and domestic uses of these bioassays are typically limited by high costs, long assay times, the requirement for specialised infrastructure, ethical considerations, significant data variability and low specificity towards specific metals. Recently, SYBR Green I-based sensors such as HazardScreen® (HS®) assay have been used to assess additive, synergistic or antagonistic toxicity effects of heavy metals in water (Foreman et al. 2011). Strong correlations of results have been shown between the Microtox® sensor, the Ceriodaphnia dubia bioassays and the HazardScreen DNA-based sensor. Until recently, bioassays have been unable to identify the individual toxicants that contribute to the overall toxicity of complex aqueous solutions (Chang et al. 1981; Foreman et al. 2011). Recently developed sensors use a variety of methods of quantifying the toxicity of trace quantities of metals in drinking water. These new biosensors are becoming increasing cost-effective and in delivering fast in situ and real-time results. The sensitives and overall mechanisms of actions of newly published biosensors for copper, cadmium, lead, mercury and aluminium are compiled in Tables 1, 2, 3, 4 and 5, respectively.

Table 1.

Copper biosensors. Copper detection limits of each sensor with the linear range in parenthesis (if reported) are listed in column two

Ion-selective receptor molecule Detection limit (linear range) Sensor mechanism References
Au NPs ~ 1 nM Functionalized cysteine-Au NPs Gooding et al. 2009
6-Acetyl-2-hydroxynaphthalene 8.5 nM Using a reaction-based fluorescent probe Ren et al. 2018
2-Dicyanomethylene-3-cyano-4.5.5-trimethyl-2,5-dihydrofuran 13 nM Colorimetric fluorescent probe based on dihydrofuran with a picolinate moiety Xu et al. 2018a, b
DsRed protein < 15.7 nM Fluorescence utilising the wild-type red fluorescent protein, DsRed Sumner et al. 2006
Neoprene 15.7 nM Voltammetry screen-printed thick-film neoprene Malzahn et al. 2011
Transgenic zebrafish 15.7 nM Fluorescence using a metal-responsive promoter linked to a fluorescent reporter gene (DsRed2) Pawar et al. 2016
cDNA of drFP583 100 nM Fluorescence assays utilising drFP583-pRSETB expression plasmids in Escherichia coli Bereza-Malcolm et al. 2016
Yeast 110 nM Amperometry Jarque et al. 2016
Bismuth nanoparticles 0.4 μM Nano composite of reduced graphene oxide–bismuth nanoparticles Sahoo et al. 2013
Natural tripeptide GGH (Gly-Gly-His) moiety 0.44 μM Fluorescence using a fluorophore-tripeptide probe (C-Gly-Gly-His) Hao et al. 2015
Saccharomyces cerevisiae 0.5 μM S. cerevisiae cells harbouring plasmid pYEX-GFPuv with a cup::gfp construct Shetty et al. 2004
Coumarin 0.64 μM Fluorescence utilising N′-acetyl-2-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)acetohydrazide (HMC1) Warrier and Kharkar 2018
Au NPs 1 μM Au NPs bound to N,N′-2,6-diisopropylphenyl-1,7-bis(4-hydroxypyridine) perylene-3,4,9,10-tetracarboxylic acid bisimide He et al. 2005
Alcaligenes eutrophus (AE1239) 1 μM (0–25 μM) Fluorescence utilising optical bioluminescent of Alcaligenes eutrophus (AE1239) with Vibrio fischeri luxCDABE operon under the influence of a copper-induced promoter Suzanne et al. 2002
Anabaena torulosa 1.2 μM (2.5–10 μM) Fluorescence utilising cyanobacteria via whole-cell entrapment on cellulose membranes Wong et al. 2013
Graphene QDs 2 μM (1–50 μM) Fluorescent utilising the unfolding of C60 Buckminsterfullerene-derived graphene QDs Ciotta et al. 2017
Naphthalene diimide 4.0 μM Fluorescence utilising the “turn-on” luminescence of an azathiacrown ether-substituted naphthalene diimide Zong et al. 2016
DNAzymes 6.5 μM (6.5–40 μM) Electrode surface modification by DNAzyme-catalysed oxidation of ascorbic acid Ocaña et al. 2013
Au NPs 10 μM L-cysteine-functionalized Au NPs Yang et al. 2007
Calix[4]arene 14 μM (19–115 μM) Colorimetry using functionalized calix[4]arene Bhatt et al. 2017
Macro-metallocycle 15 μM Fluorescence and UV spectroscopy using macro-metallocycle Liu et al. 2018
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Au NPs gold nanoparticles, QDs quantum dots

Table 2.

Cadmium biosensors. Receptor molecules are listed in column one. Cadmium detection limits of each sensor with the linear range in parenthesis (if known) are listed in column two

Ion-selective receptor molecule Detection limit (linear range) Sensor mechanism References
CNTs 2.2 pM Colorimetric and electrochemical microfluidic paper-based analytical devices using screen-printing multi-walled CNTs Rattanarat et al. 2014
Porous magnesium oxide nano-flowers 81 pM (40–140 nM) Porous magnesium oxide nano-flowers sensitive electrode monitoring using square-wave anodic stripping voltammetry Wei et al. 2012
Yeast 0.2 nM Amperometry Jarque et al. 2016
CNTs 0.27 nM (0.44–178 nM) Differential pulse anodic stripping voltammetry using glassy carbon electrode modified with Nafion, poly(2,5-dimercapto-1,3,4-thiadiazole) and multi-walled CNTs He et al. 2011
Polyaniline nanofibers 0.7 nM (5–80 nM) Square-wave anodic stripping voltammetry using glassy carbon electrode modified with self-doped polyaniline nanofibers/mesoporous carbon nitride and bismuth Zhang et al. 2016a, b, c
C18 silica monolith column 0.8 nM (0.44–44 μM) Reversed-phase high-performance liquid chromatography Thirumalai et al. 2018
Au NPs 3.5 nM (10–30 μM) Colorimetric assay using trithiocyanuric acid-functionalized Au NPs and ascorbic acid Wang et al. 2018
Screen-printed thick-film electrodes 4.4 nM (0–1.3 μM) Standard electrochemical couple of potassium ferrocyanide-ferricyanide and solid thick-film electrodes Prášek et al. 2006
Glutathione 5 nM Voltammetry using glutathione as a selective ligand immobilised on a gold electrode modified with a self-assembled monolayer of 3-mercaptopropionic acid Chow et al. 2005
Transgenic zebrafish 8.9 nM Metal-responsive promoter linked to a fluorescent reporter gene (DsRed2) Pawar et al. 2016
Whole-cell bacterial fluorescence 10 nM Staphylococcus aureus strain RN4220 and Bacillus subtilis strain BR151 using the regulatory sequence from the cadA gene of plasmid pI258 Tauriainen et al. 1998
Bismuth nanoparticles 20 nM Nano composite of reduced graphene oxide–bismuth nanoparticles Sahoo et al. 2013
Anabaena torulosa 27 nM (0.5–10 μM) Optical transduction using whole-cell entrapment on cellulose membrane Wong et al. 2013
CNTs 0.4 μM (0.4–71 μM) CNTs nanoelectrode array/epoxy voltammetry Liu et al. 2005
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CNTs carbon nanotubes, Au NPs gold nanoparticles

Table 3.

Lead biosensors. Receptor molecules are listed in column one. Lead detection limits of each sensor with the linear range in parenthesis (if known) are listed in column two

Ion-selective receptor molecule Detection limit (linear range) Sensor mechanism References
GR-5 DNAzyme 0.9 pM (2–1000 pM) Electrochemiluminescence using the GR-5 lead-dependent DNAzyme and Pb-induced release of ruthenium tris (1,10-phenanthroline) (Ru(phen)32þ) Gao et al. 2013
CNTs 1.2 pM Colorimetric and electrochemical microfluidic paper-based analytical devices using screen-printing multi-walled CNTs Rattanarat et al. 2014
Porous magnesium oxide nano-flowers 2.1 pM (3.3–22 nM) Porous magnesium oxide nano-flowers sensitive electrode monitoring using square-wave anodic stripping voltammetry Wei et al. 2012
DNAzymes and CdS QDs modified ssDNA 7.8 pM Biosensor based on DNAzyme, rolling circle amplification (RCA) and CdS QDs modified ssDNA Tang et al. 2013
Self-doped polyaniline nanofibers 0.2 nM (5–80 nM) Square-wave anodic stripping voltammetry using glassy carbon electrode modified with self-doped polyaniline nanofibers/mesoporous carbon nitride (and bismuth) Zhang et al. 2016a, b, c
CNTs 0.24 nM (0.48–106 nM) Differential pulse anodic stripping voltammetry using glassy carbon electrode modified with Nafion, poly(2,5-dimercapto-1,3,4-thiadiazole) and multi-walled carbon nanotubes He et al. 2011
C18 silica monolith column 0.36 nM (0.24–24 μM) Reversed-phase high-performance liquid chromatography Thirumalai et al. 2018
G-rich DNA 0.4 nM (1 nM–1 mM) Pb2+-induced G-rich DNA conformational switch from a random-coil to G-quadruplex (G4) with crystal violet as the G4-binding indicator Li et al. 2011a, b
Silica nanoparticles 0.48 nM (4.8–145 nM) Screen-printed carbon electrode modified with functionalized mesoporous silica nanoparticles Sánchez et al. 2010
Nano-structured polymer nanoparticles 0.6 nM (1.0 to 0.08 nM) Voltammetry using carbon-paste electrodes modified with nano-structured ion-imprinted polymer nanoparticles Alizadeh and Amjadi 2011
DNAzyme 0.5 nM (1 nM–1 μM) Amperometric sensing platform for detection of Pb-based on horseradish peroxidase (HRP)-mimicking DNAzyme-catalysed template-guided deposition of polyaniline (PANI) that catalysed the oxidation of anilineto PANI with H2O2 Li et al. 2013a, b
G-rich DNA with redox probe 0.5 nM Conformational switch from hairpin DNA to G-quadruplex induced by Pb2+ by electrochemical impedance spectroscopy (EIS) in the presence of [Fe(CN)6]3−/4− as the redox probe Lin et al. 2011
Nano hydroxyapatite 1 nM Voltammetry using a nafion conductive matrix and a modified glassy carbon electrode for composed of nanosized hydroxyapatite coupled to an ionophore Pan et al. 2009
Bismuth nanoparticles 2.7 nM Nano composite of reduced graphene oxide–bismuth nanoparticles Sahoo et al. 2013
DNAzymes and SYBER Green I 5 nM (0–50 nM) Fluorescence based on DNAzyme activation and cDNA strang cleavage via an RNA site Ravikumar et al. 2017
Au NP-functionalized graphene 10 nM (50–1000 nM) Fluorescence using Au NP-functionalized graphene in the presence of both thiosulfate and 2-mercaptoethanol Fu et al. 2012
Graphene QDs and Au NPs 16.7 nM (50 nM–4 μM) Fluorescence using graphene QDs and Au NPs Niu et al. 2018
Phormidium sp. 25 nM (50 nM–20 μM) Voltammetry using non-immobilised whole cells Yüce et al. 2010
Whole-cell bacterial fluorescence 33 nM Staphylococcus aureus strain RN4220 and Bacillus subtilis strain BR151 employing the regulatory sequence from the cadA gene of plasmid pI258 Tauriainen et al. 1998
Fluorescence-labelled oligonucleotides 61 nM (0.1–1 μM) Fluorescence using a fluorescence-labelled aptamer from complex with a quencher-labelled short complementary sequence Chen et al. 2018
Gram-negative whole-cell bacteria 0.97 μM Plasmid-based whole-cell Pseudomonas aeruginosa bacterial biosensors using the PAO1(pBBpbrRgfp) genetic element Bereza-Malcolm et al. 2016
Anabaena torulosa 0.1 μM (0.5–5 μM) Whole-cell entrapment on cellulose membrane Wong et al. 2013
Au NPs 0.1 μM Surface-enhanced resonance Raman scattering (SERS) utilising 2-mercaptoisonicotinic acid-modified Au NPs Zamarion et al. 2008
DNAzyme 0.3 μM Electrochemical sensor based on 8–17 lead-dependent DNAzyme immobilised on a gold electrode Xiao et al. 2007
6-Carboxyfluorescein and Cy5 1 μM Visual detection using Au NPs, DNAzyme microparticles and 6-carboxyfluorescein and Cy5 Kim and Lee 2016
Graphene QDs 2 μM (30–100 μM) Fluorescent using unfolded fullerene QDs Ciotta et al. 2017
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CNTs carbon nanotubes, Au NPs gold nanoparticles, ssDNA single-stranded DNA, QDs quantum dots

Table 4.

Mercury sensors. Receptor molecules are listed in column one. Mercury detection limits of each sensor with the linear range in parenthesis (if reported) are listed in column two

Ion-selective receptor molecule Detection limit (linear range) Sensor mechanism References
Au NPs 2.5 fM Surface enhancement Raman spectrum (SERS) spot tests using Au NPs and dithizone Grasseschi et al. 2010
Single-walled carbon nanotubes 3 fM (10 fM–1 μM) Voltammetry using a gold substrate with tunable vertically aligned single-walled carbon nanotubes and a target recycling strategy Shi et al. 2017
Chlorella vulgaris 10 fM Electrochemical amperometry using algae-bovine serum albumin cross-linked with glutaraldehyde Singh and Mittal 2012
Silver-coated Au NPs 10 fM SERS silicon wafer modified with 4,4′-dipyridyl (DPy) Du et al. 2013
Magnetic substrate CoFe2O4Ag and single-walled carbon nanotubes 0.84 pM (1 pM–100 nM) SERS optometry utilising a stable thymine-Hg2+-thymine structure and the π-π interaction between single-stranded DNA and single-walled carbon nanotubes Yang et al. 2017
Au NPs 1 pM SERS sensor for Hg2+ detection by using nanoporous gold as a substrate and Cy5-labelled aptamer as optical tags Zhang et al. 2013
Ag NPs 1 pM SERS using a L-cysteine-functionalized AgNP attached with Raman-labelling molecules 3,5-dimethoxy-4-(60-azobenzotriazolyl)phenol Li et al. 2013a, b
Lysozyme type VI-stabilised gold nanoclusters (Lys VI-Au NCs) 3 pM Fluorescence quenching using lysozyme type VI-stabilised Lys VI-Au NCs of methyl mercury. Detection limit of 4 nM reported for methyl mercury Lin and Tseng 2010
Self-assembled gold nanostar dimer 4 pM SERS using self-assembled gold nanostar dimers Ma et al. 2013
QDs 4.6 pM Fluorescence based on QDs and oligonucleotides Gao et al. 2018
Au NPs 10 pM Rhodamine B (RB) protected Au NPs in in soil, water and fish Darbha et al. 2007
Au/polyaniline composite nanospheres 10 pM Dandelion-like Au/polyaniline composite nanospheres used as SERS sensors Wang et al. 2011
Au NPs 25 pM SERS utilising Au NPs functionalized with 4-mercaptobenzoic acid in the presence of 2,6-pyridinedicarboxylic acid Peng et al. 2017
Bimetallic Au–Pt nanoparticles 38.9 pM Anodic stripping voltammetry using bimetallic Au–Pt nanoparticles/organic nanofiber glassy carbon electrodes Gong et al. 2010
Rhodamine 6G dye 0.06 nM Au NP-(rhodamine 6G dye)-based fluorescent sensor Chen et al. 2007
Au nanowire 0.1 nM Au nanowire on-film surface-enhanced resonance Raman scattering (SERS) sensor for Hg2+ based on Hg2+-T coordination Taejoon et al. 2011
Droplet-based microfluidic system 0.1–2.5 nM Quantification achieved using a droplet-based microfluidic system Li et al. 2012
Semiconductor QDs and Au NPs 0.49–0.87 nM Time-gated fluorescence resonance energy transfer (TGFRET) sensing strategy using DNA-functionalized Mn-doped CdS/ZnS QDs and Au NPs Huang et al. 2013
Transgenic zebrafish 0.1 nM Metal-responsive promoter linked to a fluorescent reporter gene (DsRed2) Pawar et al. 2016
Ag nanoclusters (Ag Cs) 0.1 nM (0.1 nM–10 μM) “Turn-off” Hg2+ sensors using Ag NCs stabilised with glutathione Wang et al. 2012a, b, c
ZnSe/ZnS colloidal nanoparticles 0.1 nM (0–20 nM) Fluorescence based on mercaptopropionic acid-coated Mn-doped ZnSe/ZnS colloidal nanoparticles Ke et al. 2014
Mn:CdS/ZnS QDs and Au NPs 0.18 nM Enhanced signal enhancement achieved with resonance energy transfer (FRET) via Au NPs functionalized with 10-mer DNA (strand B) that quench the fluorescence of Mn:CdS/ZnS QDs functionalized with 33-mer thymine-rich DNA (strand A) Changqing et al. 2005
Au nanoclusters 0.3 nM (0.75 nM–5 μM) Fluorescence using gold nanoclusters tuned with bovine serum albumin and bromelain Bhamore et al. 2018
Au/graphene electrode 0.5 nM Mercury-induced charge transfer resistance of oligonucleotide-gold electrodes Wang et al. 2012a, b, c
ZnO nanorods 0.5 nM, (0.5 nM–20 mM) Potentiometry using glucose oxidase immobilised on Zinc oxide nanorods and gold-coated glass electrodes Chey et al. 2012
C18 silica monolith column 0.6 nM (0.25–25 μM) Reversed-phase high-performance liquid chromatography Thirumalai et al. 2018
Ag NPs 1 nM Colorimetric and a “turn-on” fluorescent sensor using folic acid-functionalized Ag NPs Dongyue et al. 2014
Au NPs 1 nM Para-aminothiophenol coupled Au NPs (PATP-Au) multilayer as SERS probes Ma et al. 2012
Fluorescently labelled DNA oligonucleotides 1.2 nM (0–1 μM) Evanescent-wave optical fibres using structure-switching DNA and a fluorescence-labelled complementary DNA oligonucleotide Long et al. 2013
Carbonothioate 1.4 nM (0–0.8 μM) Rhodol-derived colorimetric and fluorescent with a recognition receptor of carbonothioate Duan et al. 2017
DNA-conjugated QDs 6 nM Fluorescence using nanometal surface energy transfer in DNA-conjugated QDs and Au nanoparticles as part of a QDs/DNA/Au NPs ensemble Li et al. 2011a, b
Au NPs 2.8 nM (5 nM–1 μM) Colorimetric assay using trithiocyanuric acid-functionalized Au NPs and ascorbic acid Wang et al. 2018
Ag NP 3.3 nM Colorimetry based on an Ag NP paper-based device utilising the morphology transition of 1-dodecane-thiol (C12H25SH)-capped Ag nano prisms in the presence of excess iodide Chen et al. 2013
Ag NCs 2 nM Poly(acrylic acid)-templated Ag NCs as a platform for fluorescence “turn-on” detection Tao et al. 2012
Ag NCs 4 nM Ratiometric fluorescent probe using DNA-stabilised Ag NCs MacLean et al. 2013
Denatured ovalbumin-coated CdTe QDs 4.2 nM 3-Mercaptopropionic acid-stabilised CdTe QDs coated with chemically denatured ovalbumin Wang et al. 2012a, b, c
CdS NPs 4.5 nM Synchronous fluorescence based on glutathione-capped CdS NPs Liang et al. 2010
Ag NP 5 nM Ag NP-embedded poly(vinyl alcohol) (Ag-PVA) thin film Ramesh and Radhakrishnan 2011
ZnS QDs 5 nM Water-soluble ZnS QDs capped with N-acetyl-L-cysteine Duan et al. 2011
Au NPs 5 nM Fluorescence quenching of 11-mercapto-undecanoic acid-protected gold nanoparticles in the presence of 2,6-pyridine dicarboxylic acid Chih-Ching et al. 2007
Au NPs 6 nM Photoluminescence quenching of perylene bisimide chromophores by Au NPs He et al. 2007
Au NPs 9.93 nM Photoluminescence quenching of rhodamine-Au NPs complexes Huang and Chang 2006
Ag NCs 10 nM “Turn-on” fluorescence sensor based on DN duplexes and Ag NCs Deng et al. 2011
Oligothiophene 10.3 nM Colorimetry and ratiometric fluorescence using the probe 5-(1,3-dithiolan-2-yl)-2,2′:5′,2″-terthiophene Lan et al. 2018
Au NPs 14.9 nM Colorimetry using Au NPs tethered by a linker oligonucleotide with thymine−thymine mismatches Xue et al. 2008
UiO-66-NH2 and a T-rich FAM-labelled ssDNA 17.6 nM (0.14 μM) Fluorescence using a Metal–Organic Framework/DNA Hybrid System (UiO-66-NH2) sensing material Lan-Lan et al. 2016
Au NPs 25 nM Tryptophan-protected popcorn-shaped Au NPs-based SERS probe Senapati et al. 2011
Au NPs 25 nM Hyper-Rayleigh scattering of Au NPs Darbha et al. 2008
Ag NPs 25 nM Starch-stabilised Ag NPs colorimetry Fan et al. 2009
Au NPs 34 nM 2-Mercaptoisonicotinic acid-modified Au NPs Zamarion et al. 2008
New rhodamine-based fluorescent probe 38 nM Fluorescence based on a new rhodamine-based fluorescent probe Zhang et al. 2016a, b, c
Au NPs 40 nM Colorimetric and fluorescent dual sensor using Au NPs and fluorescein (FAM)-tagged ssDNA with mismatched T-T sequences Wang et al. 2008
Ag NPs 45 nM Polyhedral Ag NPs colorimetry Bera et al. 2010
2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt 50 nM Colorimetry utilising G-quadruplex-based DNAzymes and H2O2-mediated oxidation of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt Li et al. 2009
PVA-Ag-NPs 50 nM (50 nM–25 μM) PVA-Ag-NPs nanocomposite thin film Sarkar et al. 2017
Condensed fluorophore of Changsha dye and 4-Phenyl-3-thiosemicarbazide 58 nM (0.5–5 μM) Near-infrared fluorescence via an irreversible spirolactam ring-opening process and a condensed probe of Changsha dye and 4-Phenyl-3-thiosemicarbazide Jiaoliang et al. 2017
Carbonothioate 55 nM (0–16 μM) Carbonothioate-based fluorescent probe using 2-(2′-hydroxyphenyl)benzothiazole as the fluorophore Xu et al. 2018a, b
Au NPs 100 nM Colorimetry using L-cysteine-functionalized Au NPs Fang et al. 2010
Benzothiazole-derived chemosensor “L” 0.11 μM Excited-state intramolecular proton transfer mechanism using a benzothiazole-derived chemosensor “L” Sahana et al. 2015
Metallothioneins 225 nM Metallothionein-impregnated paper discs on screen-printed carbon electrodes Irvine et al. 2017
Carbon NDs 0.23 μM Fluorescent using nitrogen-doped carbon QDs Zhang and Chen 2014
Dendritic compounds RhB-BODIPY 334 nM Intramolecular fluorescence resonance energy transfer (FRET) using rhodamine coupled with the dendritic compound RhB-BODIPY Shen and Qian 2017
Carbon dots 0.47 μM (1–100 μM) Ratiometric fluorescence using rhodamine B hydrazide and carbon dots Yusha et al. 2018
Micro-electro-mechanical sensors 0.5 μM Concrete non-destructive air-coupled micro-electro-mechanical sensors Ham and Popovics 2015
Naphthalene diimide 1.3 μM Fluorescence using a naphthalene diimide-based probe (NDI-5) Zong et al. 2017
Ag NPs 2.2 μM Unmodified Ag NPs colorimetry Farhadi et al. 2012
NBD-Cl 23 μM (0–20 μM) Colorimetry and ratiometric fluorescence NBD-Cl Zhang et al. 2016a, b, c
Ag NPs ~ 60 μM Green-synthesised Ag NPs using plant extracts Karthiga and Anthony 2013
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Au NPs gold nanoparticles, Pd NPs palladium nanoparticles, NDs nano dots, Ag NPs silver nanoparticles, Ag NCs silver nanoclusters, PVA-Ag-NPs silver nanoparticle-impregnated poly(vinyl alcohol), SERS surface enhancement Raman spectrum, QDs quantum dots, NBD-Cl 4-chloro-7-nitrobenzo-2,1,3-oxadiazole

Table 5.

Aluminium sensors. Receptor molecules are listed in column one. Aluminium detection limits of each sensor with the linear range in parenthesis (if known) are listed in column two

Ion-selective receptor molecule Detection limit (linear range) Sensor mechanism Reference
Methylene blue 0.2 nM Exonuclease III activity of DNA oligonucleotides and methylene blue-labelled T-rich probes Xuan et al. 2013
Au NPs 0.5 nM Au NP-functionalized DNA Kong et al. 2009
Au NPs 2.3 nM Electrochemical stripping assay using thiolated amino acid-capped Au NPs in a carbon ionic liquid electrode Safavi and Farjami 2011
Pd NPs 2 μM Amperometry using superoxide dismutase and glutaraldehyde on screen-printed carbon electrodes modified with tetrathiofulvalene and Pd NPs Barquero-Quirós and Arcos-Martínez 2016
Au NPs 3.6 μM (2–18 μM) Colorimetry using ethylenediaminetetraacetic acid (EDTA)-capped Au NPs Siewdorlang and Devendra 2016
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The author of this review presents a compilation of various published sensor mechanisms and the molecular basis for their high degree of selectivity for either copper, cadmium, lead, mercury and/or aluminium. All techniques are listed in order of their sensitivities in aqueous solutions. Analytical techniques presented here include fluorescence, voltammetry, inductively coupled plasma techniques, spectrophotometry and colorimetry. The aim of this review is to identify which techniques display the highest degree of sensitivity for the selected heavy metals. Furthermore, the author is happy to discuss any areas of further optimisation and provide helpful suggestions to developers of sensors for the selected heavy metals.

Discussion and concluding remarks

This review gives a brief overview of the current mechanisms used to construct biosensors and their detection limits. There are a few clear trends from this review. Firstly, nanoparticles (NPs) are becoming increasingly used in the construction of the most sensitive biosensors. Secondly, simple NP receptor molecules are insufficient and require continual optimisation. Surface modifications and/or forming complex structures greatly improve sensitivities. Thirdly, more work is needed to verify not just the detection limits, but also the sensitivities of these biosensors to their target analytes. For example, authors should test the robust nature of their biosensors by adding trace amounts of metal to samples of river and sea water once they have optimised their techniques. The clear contribution of nanotechnology and biotechnology to the performance of the reviewed biosensors suggests that rapid performance improvements are in progress to develop commercial tests in real-time systems. It is crucial that testing technology move away from infrastructure-intensive sensors such as atomic absorption spectroscopy (Vil’pan et al. 2005), cold vapour atomic fluorescence spectrometry (Yan et al. 2002), inductively coupled plasma mass spectrometry (Moreton and Delves 1998), electrochemical methods (Liu et al. 2009), gas chromatography (Fitzgerald and Gill 1979) and high-performance liquid chromatography (Balarama Krishna et al. 2007). There is a need to develop new portable and rapid biosensors that can be used even by school children with minimal training (Foreman et al. 2011). However, important considerations of biosensors designed for use in rural areas of developing countries are low cost, and a long shelve half-life of certain reagents (e.g., enzymes and oligonucleotides) (Fernandez-Lafuente 2009; Gibson et al. 1992; Panjan et al. 2017).

Author contributions

All authors wrote, revised and approved the final manuscript.

Conflict of interest

Vangelis George Kanellis declares that he has no conflicts of interest.

Ethical approval

This article does not contain any studies with human participants or animals performed by the author.

References

  1. Alizadeh T, Amjadi S. Preparation of nano-sized Pb2+ imprinted polymer and its application as the chemical interface of an electrochemical sensor for toxic lead determination in different real samples. J Hazard Mater. 2011;190(1–3):451–459. doi: 10.1016/j.jhazmat.2011.03.067. [DOI] [PubMed] [Google Scholar]
  2. Balarama Krishna MV, et al. Online mercury speciation through liquid chromatography with particle beam/electron ionization mass spectrometry detection. J Anal At Spectrom. 2007;22(3):283–291. doi: 10.1039/B609362K. [DOI] [Google Scholar]
  3. Bang SH, et al. Toxicity assessment of titanium (IV) oxide nanoparticles using Daphnia magna (water flea) J Environ Health Toxicol. 2011;26:e2011002. doi: 10.5620/eht.2011.26.e2011002. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Barquero-Quirós M, Arcos-Martínez M. Effect of nanoparticles on modified screen printed inhibition superoxide dismutase electrodes for aluminum. Sensors. 2016;16(10):1588. doi: 10.3390/s16101588. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bera RK, Das AK, Raj CR. Enzyme-cofactor-assisted photochemical synthesis of Ag nanostructures and shape-dependent optical sensing of Hg(II) ions. Chem Mater. 2010;22(15):4505–4511. doi: 10.1021/cm1013762. [DOI] [Google Scholar]
  6. Bereza-Malcolm L, Aracic S, Franks AE. Development and application of a synthetically-derived lead biosensor construct for use in gram-negative bacteria. Sensors. 2016;16(12):2174. doi: 10.3390/s16122174. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Bhamore JR, et al. Tuning of gold nanoclusters sensing applications with bovine serum albumin and bromelain for detection of Hg2+ ion and lambda-cyhalothrin via fluorescence turn-off and on mechanisms. Anal Bioanal Chem. 2018;410(11):2781–2791. doi: 10.1007/s00216-018-0958-1. [DOI] [PubMed] [Google Scholar]
  8. Bhatt M, et al. Functionalized calix[4]arene as a colorimetric dual sensor for Cu(ii) and cysteine in aqueous media: experimental and computational study. New J Chem. 2017;41(21):12541–12553. doi: 10.1039/C7NJ02537H. [DOI] [Google Scholar]
  9. Chang JC, Taylor PB, Leach FR. Use of the Microtox® assay system for environmental samples. Bull Environ Contam Toxicol. 1981;26(1):150–156. doi: 10.1007/bf01622069. [DOI] [PubMed] [Google Scholar]
  10. Changqing Z, et al. Functional InP nanocrystals as novel near-infrared fluorescent sensors for mercury ions. Chem Lett. 2005;34(7):898–899. doi: 10.1246/cl.2005.898. [DOI] [Google Scholar]
  11. Chen J, et al. A functionalized gold nanoparticles and Rhodamine 6G based fluorescent sensor for high sensitive and selective detection of mercury(II) in environmental water samples. Anal Chim Acta. 2007;599(1):134–142. doi: 10.1016/j.aca.2007.07.074. [DOI] [PubMed] [Google Scholar]
  12. Chen L, Fu X, Lu W, Chen L. Highly sensitive and selective colorimetric sensing of Hg2+ based on the morphology transition of silver nanoprisms. ACS Appl Mater Interfaces. 2013;5(2):284–290. doi: 10.1021/am3020857. [DOI] [PubMed] [Google Scholar]
  13. Chen Y, et al. Selection of DNA aptamers for the development of light-up biosensor to detect Pb(II) Sensors Actuators B Chem. 2018;254:214–221. doi: 10.1016/j.snb.2017.07.068. [DOI] [Google Scholar]
  14. Chey C, et al. Indirect determination of mercury ion by inhibition of a glucose biosensor based on ZnO nanorods. Sensors. 2012;12(11):15063. doi: 10.3390/s121115063. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Chih-Ching H, et al. Synthesis of highly fluorescent gold nanoparticles for sensing mercury(II) Angew Chem Int Ed. 2007;46(36):6824–6828. doi: 10.1002/anie.200700803. [DOI] [PubMed] [Google Scholar]
  16. Chow E, Hibbert DB, Gooding JJ. Voltammetric detection of cadmium ions at glutathione-modified gold electrodes. Analyst. 2005;130(6):831–837. doi: 10.1039/B416831C. [DOI] [PubMed] [Google Scholar]
  17. Chowdhury S, et al. Heavy metals in drinking water: occurrences, implications, and future needs in developing countries. Sci Total Environ. 2016;569-570:476–488. doi: 10.1016/j.scitotenv.2016.06.166. [DOI] [PubMed] [Google Scholar]
  18. Ciotta E, et al. Sensitivity to heavy-metal ions of unfolded fullerene quantum dots. Sensors. 2017;17(11):2614. doi: 10.3390/s17112614. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Darbha GK, Ray A, Ray PC. Gold nanoparticle-based miniaturized nanomaterial surface energy transfer probe for rapid and ultrasensitive detection of mercury in soil, water, and fish. ACS Nano. 2007;1(3):208–214. doi: 10.1021/nn7001954. [DOI] [PubMed] [Google Scholar]
  20. Darbha GK, et al. Selective detection of mercury (II) ion using nonlinear optical properties of gold nanoparticles. J Am Chem Soc. 2008;130(25):8038–8043. doi: 10.1021/ja801412b. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Deng L, et al. Fluorescent silver nanoclusters in hybridized DNA duplexes for the turn-on detection of Hg2+ ions. Chem Commun. 2011;47(39):11065–11067. doi: 10.1039/C1CC14012D. [DOI] [PubMed] [Google Scholar]
  22. Dongyue S, et al. Folic acid functionalized silver nanoparticles with sensitivity and selectivity colorimetric and fluorescent detection for Hg 2+ and efficient catalysis. Nanotechnology. 2014;25(35):355702. doi: 10.1088/0957-4484/25/35/355702. [DOI] [PubMed] [Google Scholar]
  23. Du Y, et al. Surface-enhanced Raman scattering chip for femtomolar detection of mercuric ion (II) by ligand exchange. Anal Chem. 2013;85(6):3160–3165. doi: 10.1021/ac303358w. [DOI] [PubMed] [Google Scholar]
  24. Duan J, et al. Facile synthesis of N-acetyl-l-cysteine capped ZnS quantum dots as an eco-friendly fluorescence sensor for Hg2+ Talanta. 2011;85(4):1738–1743. doi: 10.1016/j.talanta.2011.06.071. [DOI] [PubMed] [Google Scholar]
  25. Duan Q, et al. Rhodol-derived colorimetric and fluorescent probe with the receptor of carbonothioate for the specific detection of mercury ions. Anal Sci. 2017;33(10):1169–1173. doi: 10.2116/analsci.33.1169. [DOI] [PubMed] [Google Scholar]
  26. Fan Y, et al. Synthesis of starch-stabilized Ag nanoparticles and Hg(2+)recognition in aqueous media. Nanoscale Res Lett. 2009;4(10):1230–1235. doi: 10.1007/s11671-009-9387-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Fang C, et al. L-cysteine functionalized gold nanoparticles for the colorimetric detection of Hg 2+ induced by ultraviolet light. Nanotechnology. 2010;21(2):025501. doi: 10.1088/0957-4484/21/2/025501. [DOI] [PubMed] [Google Scholar]
  28. Farhadi K, et al. Highly selective Hg2+ colorimetric sensor using green synthesized and unmodified silver nanoparticles. Sensors Actuators B Chem. 2012;161(1):880–885. doi: 10.1016/j.snb.2011.11.052. [DOI] [Google Scholar]
  29. Fernandez-Lafuente R. Stabilization of multimeric enzymes: strategies to prevent subunit dissociation. Enzym Microb Technol. 2009;45(6):405–418. doi: 10.1016/j.enzmictec.2009.08.009. [DOI] [Google Scholar]
  30. Fitzgerald WF, Gill GA. Subnanogram determination of mercury by two-stage gold amalgamation and gas phase detection applied to atmospheric analysis. Anal Chem. 1979;51(11):1714–1720. doi: 10.1021/ac50047a030. [DOI] [Google Scholar]
  31. Foreman AL, et al. A DNA-based assay for toxic chemicals in wastewater. Environ Toxicol Chem. 2011;30(8):1810–1818. doi: 10.1002/etc.568. [DOI] [PubMed] [Google Scholar]
  32. Fu X, et al. “Turn-on” fluorescence detection of lead ions based on accelerated leaching of gold nanoparticles on the surface of graphene. ACS Appl Mater Interfaces. 2012;4(2):1080–1086. doi: 10.1021/am201711j. [DOI] [PubMed] [Google Scholar]
  33. Gao A, et al. Electrochemiluminescent lead biosensor based on GR-5 lead-dependent DNAzyme for Ru(phen)32+ intercalation and lead recognition. Analyst. 2013;138(1):263–268. doi: 10.1039/C2AN36398D. [DOI] [PubMed] [Google Scholar]
  34. Gao W, et al. Ultrasensitive determination of mercury ions (II) by analysis of the degree of quantum dots aggregation. Talanta. 2018;188:644–650. doi: 10.1016/j.talanta.2018.06.039. [DOI] [PubMed] [Google Scholar]
  35. Gibson TD, et al. Extended shelf life of enzyme-based biosensors using a novel stabilization system. Biosens Bioelectron. 1992;7(10):701–708. doi: 10.1016/0956-5663(92)85052-C. [DOI] [Google Scholar]
  36. Gong J, et al. Stripping voltammetric detection of mercury(II) based on a bimetallic Au−Pt inorganic−organic hybrid nanocomposite modified glassy carbon electrode. Anal Chem. 2010;82(2):567–573. doi: 10.1021/ac901846a. [DOI] [PubMed] [Google Scholar]
  37. Gooding JJ, et al. Using nanoparticle aggregation to give an ultrasensitive amperometric metal ion sensor. Electrochem Commun. 2009;11(10):2015–2018. doi: 10.1016/j.elecom.2009.08.043. [DOI] [Google Scholar]
  38. Grasseschi D, Zamarion VM, Araki K, Toma HE. Surface enhanced Raman scattering spot tests: a new insight on Feigl’s analysis using gold nanoparticles. Anal Chem. 2010;82(22):9146–9149. doi: 10.1021/ac102238f. [DOI] [PubMed] [Google Scholar]
  39. Gruber D. Biological monitoring and our water resources. Endeavour. 1989;13(3):135–140. doi: 10.1016/0160-9327(89)90088-4. [DOI] [PubMed] [Google Scholar]
  40. Ham S, Popovics JS. Application of micro-electro-mechanical sensors contactless NDT of concrete structures. Sensors (Basel, Switzerland) 2015;15(4):9078–9096. doi: 10.3390/s150409078. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Hao Y, et al. A retrievable, water-soluble and biocompatible fluorescent probe for recognition of Cu(II) and sulfide based on a peptide receptor. Talanta. 2015;143:307–314. doi: 10.1016/j.talanta.2015.04.075. [DOI] [PubMed] [Google Scholar]
  42. He X, et al. Gold nanoparticle-based fluorometric and colorimetric sensing of copper(II) ions. Adv Mater. 2005;17(23):2811–2815. doi: 10.1002/adma.200501173. [DOI] [Google Scholar]
  43. He X, et al. Gold nanoparticle-based monitoring of the reduction of oxidized to reduced glutathione. Langmuir. 2007;23(17):8815–8819. doi: 10.1021/la7011028. [DOI] [PubMed] [Google Scholar]
  44. He X, et al. Differential pulse anodic stripping voltammetric determination of Cd and Pb at a bismuth glassy carbon electrode modified with Nafion, poly(2,5-dimercapto-1,3,4-thiadiazole) and multiwalled carbon nanotubes. Microchim Acta. 2011;173(1):95–102. doi: 10.1007/s00604-010-0541-8. [DOI] [Google Scholar]
  45. Huang C-C, Chang H-T. Selective gold-nanoparticle-based “turn-on” fluorescent sensors for detection of mercury(II) in aqueous solution. Anal Chem. 2006;78(24):8332–8338. doi: 10.1021/ac061487i. [DOI] [PubMed] [Google Scholar]
  46. Huang D, et al. Highly sensitive strategy for Hg2+ detection in environmental water samples using long lifetime fluorescence quantum dots and gold nanoparticles. Environ Sci Technol. 2013;47(9):4392–4398. doi: 10.1021/es302967n. [DOI] [PubMed] [Google Scholar]
  47. Hyne RV, et al. Influence of water chemistry on the acute toxicity of copper and zinc to the cladoceran Ceriodaphnia cf dubia. Environ Toxicol Chem. 2005;24(7):1667–1675. doi: 10.1897/04-497r.1. [DOI] [PubMed] [Google Scholar]
  48. Irvine G, Tan S, Stillman M. A simple metallothionein-based biosensor for enhanced detection of arsenic and mercury. Biosensors. 2017;7(1):14. doi: 10.3390/bios7010014. [DOI] [PMC free article] [PubMed] [Google Scholar]
  49. Jarque Sergio, Bittner Michal, Blaha Ludek, Hilscherova Klara. Yeast Biosensors for Detection of Environmental Pollutants: Current State and Limitations. Trends in Biotechnology. 2016;34(5):408–419. doi: 10.1016/j.tibtech.2016.01.007. [DOI] [PubMed] [Google Scholar]
  50. Jiaoliang W, et al. A NIR fluorescent probe for the rapid detection of Hg 2+ in living cells and in vivo mice imaging. Methods Appl Fluorescence. 2017;5(2):025002. doi: 10.1088/2050-6120/aa6d8d. [DOI] [PubMed] [Google Scholar]
  51. Karthiga D, Anthony SP. Selective colorimetric sensing of toxic metal cations by green synthesized silver nanoparticles over a wide pH range. RSC Adv. 2013;3(37):16765–16774. doi: 10.1039/C3RA42308E. [DOI] [Google Scholar]
  52. Ke J, et al. Ultrasensitive quantum dot fluorescence quenching assay for selective detection of mercury ions in drinking water. Sci Rep. 2014;4:5624. doi: 10.1038/srep05624. [DOI] [PMC free article] [PubMed] [Google Scholar]
  53. Kim J, Lee JB. Giant catalytic DNA particles for simple and intuitive detection of Pb(2+) Nanoscale Res Lett. 2016;11:244. doi: 10.1186/s11671-016-1462-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  54. Kong, R.-M., et al. (2009). An ultrasensitive electrochemical “turn-on” label-free biosensor for Hg2+with AuNP-functionalized reporter DNA as a signal amplifier. Chem Commun (37), 5633–5635. 10.1039/B911163H [DOI] [PubMed]
  55. Lan L, Niu Q, Li T. A highly selective colorimetric and ratiometric fluorescent probe for instantaneous sensing of Hg2+ in water, soil and seafood and its application on test strips. Anal Chim Acta. 2018;1023:105–114. doi: 10.1016/j.aca.2018.03.023. [DOI] [PubMed] [Google Scholar]
  56. Lan-Lan W, et al. A metal–organic framework/DNA hybrid system as a novel fluorescent biosensor for mercury(II) ion detection. Chem Eur J. 2016;22(2):477–480. doi: 10.1002/chem.201503335. [DOI] [PubMed] [Google Scholar]
  57. Lanno RP, Slinger SJ, Hilton JW. Maximum tolerable and toxicity levels of dietary copper in rainbow trout (Salmo gairdneri Richardson) Aquaculture. 1985;49(3–4):257–268. doi: 10.1016/0044-8486(85)90084-5. [DOI] [Google Scholar]
  58. Li T, Dong S, Wang E. Label-free colorimetric detection of aqueous mercury ion (Hg2+) using Hg2+-modulated G-quadruplex-based DNAzymes. Anal Chem. 2009;81(6):2144–2149. doi: 10.1021/ac900188y. [DOI] [PubMed] [Google Scholar]
  59. Li F, et al. Crystal violet as a G-quadruplex-selective probe for sensitive amperometric sensing of lead. Chem Commun. 2011;47(43):11909–11911. doi: 10.1039/C1CC15023E. [DOI] [PubMed] [Google Scholar]
  60. Li M, et al. Detection of mercury(II) by quantum dot/DNA/gold nanoparticle ensemble based nanosensor via nanometal surface energy transfer. Anal Chem. 2011;83(18):7061–7065. doi: 10.1021/ac2019014. [DOI] [PubMed] [Google Scholar]
  61. Li K, et al. A stable and reproducible nanosilver-aggregation-4-mercaptopyridine surface-enhanced Raman scattering probe for rapid determination of trace Hg2+ Talanta. 2012;99:890–896. doi: 10.1016/j.talanta.2012.07.052. [DOI] [PubMed] [Google Scholar]
  62. Li F, et al. Ultrasensitive and selective detection of copper (II) and mercury (II) ions by dye-coded silver nanoparticle-based SERS probes. Biosens Bioelectron. 2013;39(1):82–87. doi: 10.1016/j.bios.2012.06.050. [DOI] [PubMed] [Google Scholar]
  63. Li F, et al. A novel and versatile sensing platform based on HRP-mimicking DNAzyme-catalyzed template-guided deposition of polyaniline. Biosens Bioelectron. 2013;41:903–906. doi: 10.1016/j.bios.2012.09.048. [DOI] [PubMed] [Google Scholar]
  64. Liang AN, et al. Synchronous fluorescence determination of mercury ion with glutathione-capped CdS nanoparticles as a fluorescence probe. Talanta. 2010;81(1):438–443. doi: 10.1016/j.talanta.2009.12.021. [DOI] [PubMed] [Google Scholar]
  65. Lin Y-H, Tseng W-L. Ultrasensitive sensing of Hg2+ and CH3Hg+ based on the fluorescence quenching of lysozyme type VI-stabilized gold nanoclusters. Anal Chem. 2010;82(22):9194–9200. doi: 10.1021/ac101427y. [DOI] [PubMed] [Google Scholar]
  66. Lin Z, et al. Pb2+ induced DNA conformational switch from hairpin to G-quadruplex: electrochemical detection of Pb2+ Analyst. 2011;136(11):2367–2372. doi: 10.1039/C1AN15080D. [DOI] [PubMed] [Google Scholar]
  67. Lithner G. Some fundamental relationships between metal toxicity in freshwater, physico-chemical properties and background levels. Sci Total Environ. 1989;87–88:356–380. doi: 10.1016/0048-9697(89)90249-0. [DOI] [Google Scholar]
  68. Liu G, et al. Ultrasensitive voltammetric detection of trace heavy metal ions using carbon nanotube nanoelectrode array. Analyst. 2005;130:1098–1101. doi: 10.1039/B419447K. [DOI] [PubMed] [Google Scholar]
  69. Liu S-J, et al. Electrochemical sensor for mercury(II) based on conformational switch mediated by interstrand cooperative coordination. Anal Chem. 2009;81(14):5724–5730. doi: 10.1021/ac900527f. [DOI] [PubMed] [Google Scholar]
  70. Liu Y, Zhao Z, Liu Q. Preparation of macrometallocycle and selective sensor for copper ion. Sci Rep. 2018;8:10943. doi: 10.1038/s41598-018-29356-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
  71. Long F, et al. Rapid on-site/in-situ detection of heavy metal ions in environmental water using a structure-switching DNA optical biosensor. Sci Rep. 2013;3:2308. doi: 10.1038/srep02308. [DOI] [PMC free article] [PubMed] [Google Scholar]
  72. Ma Y, et al. A displacement principle for mercury detection by optical waveguide and surface enhanced Raman spectroscopy. J Colloid Interface Sci. 2012;386(1):451–455. doi: 10.1016/j.jcis.2012.07.067. [DOI] [PubMed] [Google Scholar]
  73. Ma W, et al. A SERS active gold nanostar dimer for mercury ion detection. Chem Commun. 2013;49:4989–4991. doi: 10.1039/C3CC39087J. [DOI] [PubMed] [Google Scholar]
  74. MacLean JL, Morishita K, Liu J. DNA stabilized silver nanoclusters for ratiometric and visual detection of Hg2+ and its immobilization in hydrogels. Biosens Bioelectron. 2013;48:82–86. doi: 10.1016/j.bios.2013.04.002. [DOI] [PubMed] [Google Scholar]
  75. Malzahn K, et al. Wearable electrochemical sensors for in situ analysis in marine environments. Analyst. 2011;136(14):2912–2917. doi: 10.1039/C1AN15193B. [DOI] [PubMed] [Google Scholar]
  76. Moreton JA, Delves HT. Simple direct method for the determination of total mercury levels in blood and urine and nitric acid digests of fish by inductively coupled plasma mass spectrometry. J Anal At Spectrom. 1998;13:659–665. doi: 10.1039/A802242I. [DOI] [Google Scholar]
  77. Niu X, et al. A “turn-on” fluorescence sensor for Pb2+ detection based on graphene quantum dots and gold nanoparticles. Sensors Actuators B Chem. 2018;255:1577–1581. doi: 10.1016/j.snb.2017.08.167. [DOI] [Google Scholar]
  78. Ocaña C, Malashikhina N, del Valle M, Pavlov V. Label-free selective impedimetric detection of Cu2+ ions using catalytic DNA. Analyst. 2013;138:1995–1999. doi: 10.1039/C3AN36778A. [DOI] [PubMed] [Google Scholar]
  79. Pan D, et al. Nanomaterial/ionophore-based electrode for anodic stripping voltammetric determination of lead: an electrochemical sensing platform toward heavy metals. Anal Chem. 2009;81(12):5088–5094. doi: 10.1021/ac900417e. [DOI] [PubMed] [Google Scholar]
  80. Panjan P, et al. Shelf life of enzymatic electrochemical sensors. Procedia Technol. 2017;27:306–308. doi: 10.1016/j.protcy.2017.04.126. [DOI] [Google Scholar]
  81. Pawar N, et al. Development of a fluorescent transgenic zebrafish biosensor for sensing aquatic heavy metal pollution. Transgenic Res. 2016;25(5):617–627. doi: 10.1007/s11248-016-9959-z. [DOI] [PubMed] [Google Scholar]
  82. Peng Z, et al. Detection of mercury(II) with a surface-enhanced Raman scattering sensor based on functionalized gold nanoparticles. Materials Research Express. 2017;4(5):055017. doi: 10.1088/2053-1591/aa6c7b. [DOI] [Google Scholar]
  83. Prášek J, et al. New hydrodynamic electrochemical arrangement for cadmium ions detection using thick-film chemical sensor electrodes. Sensors. 2006;6(11):1498–1512. doi: 10.3390/s6111498. [DOI] [Google Scholar]
  84. Ramesh GV, Radhakrishnan TP. A universal sensor for mercury (Hg, HgI, HgII) based on silver nanoparticle-embedded polymer thin film. ACS Appl Mater Interfaces. 2011;3(4):988–994. doi: 10.1021/am200023w. [DOI] [PubMed] [Google Scholar]
  85. Rattanarat P, et al. Multilayer paper-based device for colorimetric and electrochemical quantification of metals. Anal Chem. 2014;86(7):3555–3562. doi: 10.1021/ac5000224. [DOI] [PubMed] [Google Scholar]
  86. Ravikumar A, et al. DNAzyme based amplified biosensor on ultrasensitive fluorescence detection of Pb (II) ions from aqueous system. J Fluoresc. 2017;27(6):2101–2109. doi: 10.1007/s10895-017-2149-4. [DOI] [PubMed] [Google Scholar]
  87. Ren A, et al. A novel reaction-based fluorescent probe for sensitive and selective detection of Cu2+ Inorg Chim Acta. 2018;476:136–141. doi: 10.1016/j.ica.2018.02.015. [DOI] [Google Scholar]
  88. Safavi A, Farjami E. Construction of a carbon nanocomposite electrode based on amino acids functionalized gold nanoparticles for trace electrochemical detection of mercury. Anal Chim Acta. 2011;688(1):43–48. doi: 10.1016/j.aca.2010.12.001. [DOI] [PubMed] [Google Scholar]
  89. Sahana S, et al. A 2-(2′-hydroxyphenyl)benzothiazole (HBT)–quinoline conjugate: a highly specific fluorescent probe for Hg2+ based on ESIPT and its application in bioimaging. Dalton Trans. 2015;44:20139–20146. doi: 10.1039/C5DT03719K. [DOI] [PubMed] [Google Scholar]
  90. Sahoo PK, et al. In situ synthesis and properties of reduced graphene oxide/Bi nanocomposites: as an electroactive material for analysis of heavy metals. Biosens Bioelectron. 2013;43:293–296. doi: 10.1016/j.bios.2012.12.031. [DOI] [PubMed] [Google Scholar]
  91. Sánchez A, et al. Development of screen-printed carbon electrodes modified with functionalized mesoporous silica nanoparticles: application to voltammetric stripping determination of Pb(II) in non-pretreated natural waters. Electrochim Acta. 2010;55(23):6983–6990. doi: 10.1016/j.electacta.2010.06.090. [DOI] [Google Scholar]
  92. Sarkar PK, et al. Development of highly selective and efficient prototype sensor for potential application in environmental mercury pollution monitoring. Water Air Soil Pollut. 2017;228:314. doi: 10.1007/s11270-017-3479-1. [DOI] [Google Scholar]
  93. Senapati T, et al. Highly selective SERS probe for Hg(ii) detection using tryptophan-protected popcorn shaped gold nanoparticles. Chem Commun. 2011;47(37):10326–10328. doi: 10.1039/C1CC13157E. [DOI] [PubMed] [Google Scholar]
  94. Shen B-X, Qian Y. Click synthesis, Hg2+ sensor and Intramolecular fluorescence resonance energy transfer in novel BODIPY dendrons. Sensors Actuators B Chem. 2017;239:226–234. doi: 10.1016/j.snb.2016.08.004. [DOI] [Google Scholar]
  95. Shetty RS, Deo SK, Liu Y, Daunert S. Fluorescence-based sensing system for copper using genetically engineered living yeast cells. Biotechnol Bioeng. 2004;88(5):664–670. doi: 10.1002/bit.20331. [DOI] [PubMed] [Google Scholar]
  96. Shi L, et al. A highly sensitive and reusable electrochemical mercury biosensor based on tunable vertical single-walled carbon nanotubes and a target recycling strategy. J Mater Chem B. 2017;5:1073–1080. doi: 10.1039/C6TB02658C. [DOI] [PubMed] [Google Scholar]
  97. Siewdorlang D, Devendra PSN. EDTA-capped gold nanoparticles as a colorimetric probe for aluminium. Materials Research Express. 2016;3(11):115002. doi: 10.1088/2053-1591/3/11/115002. [DOI] [Google Scholar]
  98. Singh J, Mittal SK. Chlorella sp. based biosensor for selective determination of mercury in presence of silver ions. Sensors Actuators B Chem. 2012;165(1):48–52. doi: 10.1016/j.snb.2012.02.009. [DOI] [Google Scholar]
  99. Sumner JP, et al. DsRed as a highly sensitive, selective, and reversible fluorescence-based biosensor for both Cu+ and Cu2+ ions. Biosens Bioelectron. 2006;21(7):1302–1308. doi: 10.1016/j.bios.2005.04.023. [DOI] [PubMed] [Google Scholar]
  100. Suzanne L, et al. Engineered bacteria based biosensors for monitoring bioavailable heavy metals. Electroanalysis. 2002;14:35–42. doi: 10.1002/1521-4109(200201)14:1&#x0003c;35::AID-ELAN35&#x0003e;3.0.CO;2-W. [DOI] [Google Scholar]
  101. Taejoon K, et al. Au nanowire-on-film SERRS sensor for ultrasensitive Hg2+ detection. Chem Eur J. 2011;17:2211–2214. doi: 10.1002/chem.201001663. [DOI] [PubMed] [Google Scholar]
  102. Tang S, Tong P, Li H, Tang J, Zhang L. Ultrasensitive electrochemical detection of Pb2+ based on rolling circle amplification and quantum dotstagging. Biosens Bioelectron. 2013;42:608–611. doi: 10.1016/j.bios.2012.10.073. [DOI] [PubMed] [Google Scholar]
  103. Tao Y, et al. Poly(acrylic acid)-templated silver nanoclusters as a platform for dual fluorometric turn-on and colorimetric detection of mercury (II) ions. Talanta. 2012;88:290–294. doi: 10.1016/j.talanta.2011.10.043. [DOI] [PubMed] [Google Scholar]
  104. Tauriainen S, et al. Luminescent bacterial sensor for cadmium and lead. Biosens Bioelectron. 1998;13(9):931–938. doi: 10.1016/S0956-5663(98)00027-X. [DOI] [PubMed] [Google Scholar]
  105. Thirumalai M., Kumar S. Naveen, Prabhakaran D., Sivaraman N., Maheswari M. Akhila. Dynamically modified C18 silica monolithic column for the rapid determinations of lead, cadmium and mercury ions by reversed-phase high-performance liquid chromatography. Journal of Chromatography A. 2018;1569:62–69. doi: 10.1016/j.chroma.2018.07.044. [DOI] [PubMed] [Google Scholar]
  106. Vil’pan YA, et al. Direct atomic absorption determination of mercury in drinking water and urine using a two-step electrothermal atomizer. J Anal Chem. 2005;60(1):38–44. doi: 10.1007/s10809-005-0010-4. [DOI] [Google Scholar]
  107. Wang H, Wang Y, Jin J, Yang R. Gold nanoparticle-based colorimetric and “turn-on” fluorescent probe for mercury(II) ions in aqueous solution. Anal Chem. 2008;80(23):9021–9028. doi: 10.1021/ac801382k. [DOI] [PubMed] [Google Scholar]
  108. Wang X, et al. Assembly of dandelion-like Au/PANI nanocomposites and their application as SERS nanosensors. Biosens Bioelectron. 2011;26(6):3063–3067. doi: 10.1016/j.bios.2010.11.044. [DOI] [PubMed] [Google Scholar]
  109. Wang C, et al. Fluorescent silver nanoclusters as effective probes for highly selective detection of mercury(II) at parts-per-billion levels. Chem Asian J. 2012;7(7):1652–1656. doi: 10.1002/asia.201200033. [DOI] [PubMed] [Google Scholar]
  110. Wang L, et al. Graphene enhanced electron transfer at aptamer modified electrode and its application in biosensing. Anal Chem. 2012;84(17):7301–7307. doi: 10.1021/ac300521d. [DOI] [PubMed] [Google Scholar]
  111. Wang Y-Q, et al. Highly sensitive synchronous fluorescence determination of mercury (II) based on the denatured ovalbumin coated CdTe QDs. Talanta. 2012;99:69–74. doi: 10.1016/j.talanta.2012.04.064. [DOI] [PubMed] [Google Scholar]
  112. Wang J, et al. A highly sensitive colorimetric probe for Cd2+, Hg2+ and ascorbic acid determination based on trithiocyanuric acid-AuNPs. Talanta. 2018;188:266–272. doi: 10.1016/j.talanta.2018.05.084. [DOI] [PubMed] [Google Scholar]
  113. Warrier SB, Kharkar PS. A coumarin based chemosensor for selective determination of Cu (II) ions based on fluorescence quenching. J Lumin. 2018;199:407–415. doi: 10.1016/j.jlumin.2018.03.073. [DOI] [Google Scholar]
  114. Wei Y, et al. Stripping voltammetry study of ultra-trace toxic metal ions on highly selectively adsorptive porous magnesium oxide nanoflowers. Analyst. 2012;137(9):2183–2191. doi: 10.1039/C2AN15939B. [DOI] [PubMed] [Google Scholar]
  115. Wong Ling Shing, Lee Yook Heng, Surif Salmijah. Whole Cell Biosensor UsingAnabaena torulosawith Optical Transduction for Environmental Toxicity Evaluation. Journal of Sensors. 2013;2013:1–8. doi: 10.1155/2013/567272. [DOI] [Google Scholar]
  116. Xiao Y, Rowe AA, Plaxco KW. Electrochemical detection of parts-per-billion lead via an electrode-bound DNAzyme assembly. J Am Chem Soc. 2007;129(2):262–263. doi: 10.1021/ja067278x. [DOI] [PubMed] [Google Scholar]
  117. Xu J, et al. A colorimetric and fluorescent probe for the detection of Cu2+ in a complete aqueous solution. Anal Sci. 2018;34(4):453–457. doi: 10.2116/analsci.17P517. [DOI] [PubMed] [Google Scholar]
  118. Xu J, et al. A carbonothioate-based highly selective fluorescent probe with a large Stokes shift for detection of Hg2+ Luminescence. 2018;33(1):219–224. doi: 10.1002/bio.3404. [DOI] [PubMed] [Google Scholar]
  119. Xuan F, Luo X, Hsing IM. Conformation-dependent exonuclease III activity mediated by metal ions reshuffling on thymine-rich DNA duplexes for an ultrasensitive electrochemical method for Hg2+ detection. Anal Chem. 2013;85(9):4586–4593. doi: 10.1021/ac400228q. [DOI] [PubMed] [Google Scholar]
  120. Xue X, Wang F, Liu X. One-step, room temperature, colorimetric detection of mercury (Hg2+) using DNA/nanoparticle conjugates. J Am Chem Soc. 2008;130(11):3244–3245. doi: 10.1021/ja076716c. [DOI] [PubMed] [Google Scholar]
  121. Yan X-P, et al. Flow injection on-line sorption preconcentration coupled with hydride generation atomic fluorescence spectrometry for determination of (ultra)trace amounts of arsenic(III) and arsenic(V) in natural water samples. Anal Chem. 2002;74(9):2162–2166. doi: 10.1021/ac0157019. [DOI] [PubMed] [Google Scholar]
  122. Yang W, et al. Fast colorimetric detection of copper ions using L-cysteine functionalized gold nanoparticles. J Nanosci Nanotechnol. 2007;7(2):712–716. doi: 10.1166/jnn.2007.116. [DOI] [PubMed] [Google Scholar]
  123. Yang X, He Y, Wang X, Yuan R. A SERS biosensor with magnetic substrate CoFe2O4@Ag for sensitive detection of Hg2+ Appl Surf Sci. 2017;416:581–586. doi: 10.1016/j.apsusc.2017.04.106. [DOI] [Google Scholar]
  124. Yüce M, Nazır H, Dönmez G. An advanced investigation on a new algal sensor determining Pb(II) ions from aqueous media. Biosens Bioelectron. 2010;26(2):321–326. doi: 10.1016/j.bios.2010.08.022. [DOI] [PubMed] [Google Scholar]
  125. Yusha M, et al. Ratiometric fluorescent nanosensor based on carbon dots for the detection of mercury ion. Materials Research Express. 2018;5(5):055605. doi: 10.1088/2053-1591/aac419. [DOI] [Google Scholar]
  126. Zamarion VM, et al. Ultrasensitive SERS nanoprobes for hazardous metal ions based on trimercaptotriazine-modified gold nanoparticles. Inorg Chem. 2008;47(8):2934–2936. doi: 10.1021/ic800122v. [DOI] [PubMed] [Google Scholar]
  127. Zhang R, Chen W. Nitrogen-doped carbon quantum dots: facile synthesis and application as a “turn-off” fluorescent probe for detection of Hg2+ ions. Biosens Bioelectron. 2014;55:83–90. doi: 10.1016/j.bios.2013.11.074. [DOI] [PubMed] [Google Scholar]
  128. Zhang L, et al. Nanoporous gold based optical sensor for sub-ppt detection of mercury ions. ACS Nano. 2013;7(5):4595–4600. doi: 10.1021/nn4013737. [DOI] [PubMed] [Google Scholar]
  129. Zhang C, et al. Determination of Cd2+ and Pb2+ based on mesoporous carbon nitride/self-doped polyaniline nanofibers and square wave anodic stripping voltammetry. Nanomaterials. 2016;6(1):7. doi: 10.3390/nano6010007. [DOI] [PMC free article] [PubMed] [Google Scholar]
  130. Zhang T, et al. A reversible biocompatible “turn-on” fluorescent probe for the detection of mercury(II) J Lumin. 2016;170(1):187–193. doi: 10.1016/j.jlumin.2015.10.037. [DOI] [Google Scholar]
  131. Zhang Y, et al. A colorimetric and ratiometric fluorescent probe for mercury (II) in lysosome. Sensors Actuators B Chem. 2016;224:907–914. doi: 10.1016/j.snb.2015.11.018. [DOI] [Google Scholar]
  132. Zong L, et al. A “turn-on” fluorescence probe towards copper ions based on core-substituted naphthalene diimide. Sensors Actuators B Chem. 2016;226:239–244. doi: 10.1016/j.snb.2015.11.089. [DOI] [Google Scholar]
  133. Zong L, et al. A new red fluorescent probe for Hg2+ based on naphthalene diimide and its application in living cells, reversibility on strip papers. Sensors Actuators B Chem. 2017;238:735–743. doi: 10.1016/j.snb.2016.07.052. [DOI] [Google Scholar]

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