Open Access This article is
- freely available
Biosensors 2018, 8(2), 29; doi:10.3390/bios8020029
Electrochemical Biosensors: A Solution to Pollution Detection with Reference to Environmental Contaminants
Tecnologico de Monterrey, School of Engineering and Sciences, Campus Monterrey, Ave. Eugenio Garza Sada 2501, CP 64849, Monterrey, N.L., Mexico
Exact and Natural Sciences, Institute of Biology, University of Antioquia, St. 67 No. 53-108, Medellín 050021, Colombia
Microsystems Technologies Laboratories, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
Division of Engineering in Medicine, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Cambridge, MA 02139, USA
Harvard-MIT Division of Health Sciences and Technology, MIT, Cambridge, MA 02139, USA
Authors to whom correspondence should be addressed.
Received: 27 January 2018 / Accepted: 23 March 2018 / Published: 24 March 2018
The increasing environmental pollution with particular reference to emerging contaminants, toxic heavy elements, and other hazardous agents is a serious concern worldwide. Considering this global issue, there is an urgent need to design and develop strategic measuring techniques with higher efficacy and precision to detect a broader spectrum of numerous contaminants. The development of precise instruments can further help in real-time and in-process monitoring of the generation and release of environmental pollutants from different industrial sectors. Moreover, real-time monitoring can also reduce the excessive consumption of several harsh chemicals and reagents with an added advantage of on-site determination of contaminant composition prior to discharge into the environment. With key scientific advances, electrochemical biosensors have gained considerable attention to solve this problem. Electrochemical biosensors can be an excellent fit as an analytical tool for monitoring programs to implement legislation. Herein, we reviewed the current trends in the use of electrochemical biosensors as novel tools to detect various contaminant types including toxic heavy elements. A particular emphasis was given to screen-printed electrodes, nanowire sensors, and paper-based biosensors and their role in the pollution detection processes. Towards the end, the work is wrapped up with concluding remarks and future perspectives. In summary, electrochemical biosensors and related areas such as bioelectronics, and (bio)-nanotechnology seem to be growing areas that will have a marked influence on the development of new bio-sensing strategies in future studies.
Keywords:electrochemical biosensors; screen-printed electrodes; nanowire sensors; paper-based biosensors; emerging contaminants; toxic heavy elements; detection
Across the globe, the controlled or uncontrolled release of environmental contaminants, e.g., toxic heavy elements, antibiotics, and pesticides to the environment is a serious concern . Therefore, there is an urgent need to design new prototypes to detect their presence in terrestrial and aquatic ecosystems. Low sample concentration and the lack of selectivity and sensitivity of traditional methods are among the significant bottlenecks of conventional methods. Moreover, conventional methods (e.g., chromatography) require long and specialized sample pre-treatment, which may potentially translate to time-consuming processes. In this context, electrochemical biosensors have proven to be useful tools to detect small sample volumes, low concentrations of biological components, and sometimes miniaturized analytical devices [2,3]. Recent advances in the fabrication and application of electrochemical biosensors for biomedical, agri-food, and environmental analyses have been reviewed . Electrochemical-based techniques for sensing pollutants can be categorized as potentiometric, amperometric or coulometric, voltammetric (incorporating preconcentration and stripping steps), and conductometric.
The ability to design highly specific recognition sites makes biosensors a suitable alternative to traditional chromatography-based methods . Among existing biosensors, electrochemical biosensors have various advantages such as real-time monitoring, miniaturization, and the enhancement of selectivity and sensitivity. Also, electrochemical reactions deliver electronic signals, thus, it is not necessary to use complicated signaling elements. This facilitates the development of portable systems for clinical testing and on-site environmental monitoring . Electrodes used in biosensors allow the conversion of biological signals into a readable output signal. The selectivity and sensitivity of these signals can be achieved via modification with specific biological elements such as DNA, enzymes, or cells (Figure 1). Figure 2 illustrates four different classes and sub-classes of biosensors based on the type of transducer. Based on the nature of the biological modification, electrochemical biosensors can be classified as either biocatalytic or affinity sensors. Electrochemical biocatalytic sensors are modified with biological elements able to recognize a target and induce a response of an electroactive molecule (e.g., enzymes). Meanwhile, electrochemical affinity sensors have a binding recognition element that releases a signal when it is coupled to the target (e.g., antibodies) .
There is much literature available on the utilization of biosensors for the detection of toxic heavy elements in the environment, including Pb, Cd, Hg, and Cu, and this has been reviewed elsewhere . The current literature is lacking the implementation of electrochemical biosensors for the detection/monitoring of other environmental contaminants such as emerging contaminants (ECs). Due to the growing ECs concern, and the lack of selective and sensitive methods to detect them, different electrochemical biosensors have been developed in recent years. This review aimed to present the unique potential of electrochemical biosensors with particular reference to screen-printed electrodes and nanowire sensors and their role in the pollution detection processes. The first part of the review describes several ECs with reference to pharmaceutical and pesticide-based compounds, their occurrence and adverse outcomes. The second part majorly focuses on screen-printed electrodes and nanowire sensors. The development strategies and detection modes of electrochemical biosensors at large, and screen-printed electrodes, nanowire sensors, and paper-based biosensors, in particular, are discussed in the third section of the review. Towards the end, the work is wrapped up with concluding remarks and future perspectives.
2. Emerging Contaminants (ECs)
ECs are of growing environmental concern and comprise a variety of synthetic chemicals used in different industrial practices worldwide. ECs have been classified based on use, origin and/or effects. Potential sources include pesticides and herbicides, nanomaterials, phthalates, personal care products, additives to plastic, synthetic musk, brominated compounds, phytoestrogens, and pharmaceuticals (medication including hormones, pain relievers, antibiotics, etc.) [8,9]. Besides this wider spread, no or limited information exists about the regulation or precise analytical methodologies to determine the potential risk of ECs to ecosystems and public health . Examples of EC categories derived from pharmaceutical compounds and pesticides as model sources are summarized in Table 1.
The principal route of ECs is industrial wastewater which is known to have the highest concentration of pollutants [9,11]. Also, solids produced during the wastewater treatment have diverse contaminants and are used to fertilize the agricultural fields, urban parks, and residential yards . Other compounds are discharged directly from industrial production processes into rivers or lakes and discharged chemicals move through the atmosphere and ocean currents. Ecotoxicological impacts have been reported for an array of synthetic chemicals of emerging concern. For example, endocrine disruption of fish reproduction, hormonal irregulation , renal failure in vultures by consumption of diclofenac , oxidative stress by engineered nanomaterials that damage the reproductive system of aquatic organisms , and inhibition of photosynthesis in algae caused by titanium dioxide nanoparticles . All studies listed above were run in short-term exposure to the chemicals that might be considered as ECs. However, there is not enough evidence of long-term impact . It is important to emphasize that ECs do not appear individually in the environment, which could lead to undesired synergistic effects .
ECs can also be divided according to their environmental impact, especially those have high solubility . Two of the most important groups are pharmaceuticals (over-the-counter and prescription medication) and pesticides. When these compounds reach watersheds, their structures (isoforms) change. This represents a challenge for detection and quantification. Also, there is not enough evidence concerning the behavior of pharmaceutical products and toxicity to the environment [18,19]. The main detected groups of active pharmaceuticals ingredients in the world have been antibiotics, cardiovascular drugs, lipid regulators, antidepressants, and painkillers [18,20]. The lack of information about the persistence, bioaccumulation, and toxicity of most pharmaceutical substances on the market has raised the attention of researchers worldwide.
Pesticides, e.g., cypermethrin (CYP), are being extensively employed in almost all sectors including agricultural, livestock, and households, etc. The toxicities induced by pesticides are assessed through different assays and models including in vitro, in vivo, or in situ strategies . These have been detected in high concentrations in surface and groundwater . The neurotoxicity and other significant consequences of CYP are presented in Figure 3. Pesticides are used worldwide to kill, incapacitate, or prevent pest damage to plants . The concern for pesticides as ECs is due to their environmental persistence (half-lives) over time. Studies have proven that these can remain for a long time in solids and sediments. Also, these can be accumulated in non-human organisms with acute toxic effects, such as the mass killing of biota (e.g., bees, amphibians, and fish) [22,23]. Compounds, such as DDT, HCH, toxaphene, Aldrin, and dieldrin, are still present in soils and watersheds, even after being banned in 2002 at the Stockholm convention. There are not enough mechanisms to detect these chemical groups in water, and their potential for toxic effects on aquatic fauna remains unexplored [24,25,26].
3. Electrochemical Biosensors—Development Strategies
Biosensor development depends on sensitivity, specificity, and parallelism. The approach to tackle this problem requires sensors to be produced in disposable materials of simple fabrication, have rapid responses, high accuracy, among others . In order to develop biosensors with the mentioned requirements, a profound understanding of the detection mechanism is needed.
The most explored mechanisms currently developed involve Screen-Printed Electrodes sensors (SPEs) and Nanowire sensors. Other new paths include microfluidics and µTAS. However, this work focuses on SPEs and nanowire sensors since a high amount of work has been done with these strategies and a lot more can be done. The principles to design SPEs include; materials selection, screen selection, ink selection, substrate selection, and drying and curing stages. In the case of nanowires, the challenge is the right selection of an active material and its development into a nanostructure.
In both cases, the main idea is to have an electrochemical reaction from a detectable analyte and a sensor material that is transduced as voltage, current, and impedance which finally is processed and recorded by an electronic system . The main topic of this section is about transducers as a detection mechanism for environmental application (Figure 4).
Transducers can be divided into pure electrical interfaces and electrical interfaces united with bio-receptors. The transduction mechanism, in general, is the electrochemical detection of current, charge accumulation, and conductive or impedance properties. This detection requires three electrodes i.e., (1) a reference, (2) a counter or auxiliary, and (3) a working electrode. The reference keeps a stable potential to compare with the working electrode and transduces the electrochemical reaction. The counter or auxiliary electrode establish a connection to the electrolytic solution and allow electron flow in the working electrode. Working and counting electrodes are conductive and chemically stable.
The amperometric sensor measures the electron flow from the redox reaction at a constant potential or voltage. A basic amperometric sensor uses platinum for the working electrode and Ag/AgCl for the reference electrode. Besides, if a potential linear range is scanned, the peak value in current detected is proportional to the concentration of the analyte in the solution. Since not all analytes can be redox partners, mediators are used for this electrochemical reaction. Amperometric sensors have higher sensitivity than potentiometric sensors.
Potential sensors or potentiometric devices measure the voltage or charge potential at the working electrode compared to the reference one at the equilibrium. Potentiometric sensors establish the ion activity in the reaction creating a potential difference, which is described by the Nernst equation, also related to the electromotive force (Equation (1)).where Ecell represents the potential at equilibrium. E0cell is the constant potential of the cell, R is the universal gas constant, T is the absolute temperature in Kelvin, n is the number of the electron reaction, F is the Faraday constant, and Q is the ratio of ion concentration between anode and cathode . The potentiometric devices offer stability since this mechanism does not chemically change the sample. However, the limit of detection for these types of sensors varies between 10−8 and 10−11 M .
Conductometric sensors measure the change in current flow provided by material in electrodes and media. Conversely, it is required to measure small changes in media conductivity to apply this method to low detection limits. Instead of doing direct measurements, the approach is set to immobilize complementary antibody-antigen pairs, enzymes, and DNA, among others to the electrode surfaces that lead to a real application of the conductive sensors .
Variations of the previously described mechanisms are cyclic voltammetry, chrono-amperometry and chrono-potentiometry, electrochemical impedance spectroscopy, and field effect transistor:
- Cyclic voltammetry is a periodic voltage variation measuring the change in current. The voltage variations can be performed in a wide range of patterns that lead to many forms of voltammetry. Some of the differences are polarography, linear sweep, differential staircase, normal pulse, reverse pulse, and differential pulse .
- Chrono-amperometry is a current measure of the steady state at a time when a square-wave voltage signal is applied to the working electrode. Besides, chrono-potentiometry is the voltage measured as a function of time while a constant or square-wave current is applied. In chrono-amperometry, the relation between current and analyte diffusion to the electrode is described by the Cottrell equation .
- Electrochemical impedance spectroscopy (EIS) measures the current response to an applied sinusoidal varying voltage. Exploring the frequency of the sinusoidal signal, it is possible to calculate the impedance as the real and imaginary components of the electrochemical system. EIS is a powerful tool since this technique evaluates the intrinsic material or system property of impedance, which is of high importance to biosensor development and applications .
- Field effect transistor (FET) is a configuration of a channel between two electrodes made of a semiconductor material and a transistor. The mechanism controls the electric field inside the channel along with its conductivity. A third electrode plays the role of the gate to drain the charge. This configuration allows the control channel to attract charge or repel it. In general, the array operates as a switch between conductive or non-conductive states when a drain-source voltage is higher than the gate-source and as an amplifier when it has constant current source given by the gate-source voltage. The FET technique is best used for applications with a weak signal and high impedance .
3.1. Detection Mechanism of Screen-Printed Electrodes (SPEs)
SPEs are conductive ink printed circuits on a substrate. The technique uses a mold, stencil, or mesh to cast ink into a substrate by a physical barrier, and then the printed ink is cured and fixed with an insulator layer. The substrate materials include plastics, ceramics, paper, and most recently skin . The conductive ink is desirable to be a good conductor but sometimes a material is required that interacts with the targeted analyte and previous works have used silver and carbon ink. Also, gold, platinum, noble metals, and other costly materials have been considered and tested. As said previously, SPE sensors relay on the redox reaction and its electrochemical consequences. The current properties to improve the sensing mechanism are based on; chemical modifications to increase catalysis, increase electrode surface by adding new morphologies, and stain electrodes with biomolecules to increase selectivity [30,36]. Martínez-García et al.  reported an electrochemical enzyme biosensor for 3-hydroxybutyrate detection using SPEs modified by reduced graphene oxide and thionine. Scheme of the steps involved in the preparation and functioning of the 3-hydroxybutyrate dehydrogenase (3-HBDH)/thionine (THI)/reduced graphene oxide (rGO)/screen-printed carbon electrode (SPCE) biosensor is illustrated in Figure 5. Amperometric responses were obtained according to the sequence of reactions shown in Figure 5 .
3.2. Detection Mechanism of Nanowire Sensors
As said before, the challenge in nanowire sensors fabrication is the material selection. Then, the nanostructure fabrication technique, separated into two categories, “bottom-up” and “top-down”. In the first one, construction is performed by adding material sequentially to generate a chain of molecules in a controlled manner. In the second, a reduction is shown in the base material to create the structure . The nanowires provide an excellent electron transport and optical excitation. The nanowires’ construction requires controlled dimensions, properties, and morphology. Therefore, the technology used is a solid-state crystallization with templates that include a nano-mold, anisotropic crystallographic structure, a liquid/solid interface to reduce symmetry during seed nucleation and tune growth by capping agents, more details can be found elsewhere . The materials used to fabricate nanowires are carbon nanotubes, silicon, and conducting polymers.
4. Electrochemical Biosensors—A Solution to Pollution Detection
Researchers have dedicated many years of effort to the investigation and development of technologies towards the reduction/detection of the environmental impact of hazardous compounds. Several attempts have been made to explore electrochemical sensors potentialities to detect emerging contaminants including pesticides, antibiotics, heavy metals, perfluorinated compounds, etc. This further allows acquiring fundamental data on what type of contaminant is involved and under what capacity . Electrochemical sensors and biosensors have been extensively proven to be helpful for the identification and analysis of specific compounds due to their simplicity, portability, and overall cost-effective manufacturing . Table 2 summarizes optical biosensors and electrochemical biosensors used for rapid water contaminants e.g., toxic heavy elements detection.
4.1. SPEs and Environmental Contaminants
A relatively significant issue for electrochemical sensors that utilize common, solid, and old-fashioned electrodes is the small surface area of the working electrode. They are usually designed to be miniaturized in order to provide the portability for in situ monitoring and compatibility with small amounts of sample. In other words, the size of the working surface area of an electrode in an electrochemical sensor is directly proportional to the detection efficiency of analytes . A strategy for increasing electrode surface area of contact in electrochemical biosensors, independently of the application, is the use of nanostructured materials. Various materials at the nanoscale such as metallic nanoparticles, carbon-based nanomaterials (carbon nanotubes and graphene), carbon coatings, membranes, and even some conductive polymers have been used for increasing working electrode surfaces [70,71]. The screen-printing fabrication technique offers the potential to modify the morphology of the electrodes. For said purpose, a layer-by-layer deposition of ink on a solid substrate with a removable mesh or screen allows fabrication of novel designs with enhanced contact surface area. Consequentially, it leads to more efficient readings of analytes in samples. This technology also has advantages over conventional rod-shaped electrodes regarding flexibility, the possibility of process automation, reproducibility, the availability of many materials, and the cost efficiency of electrochemical substrates [30,37].
In recent years, graphene has been proven as an outstanding candidate for screen-printed electrodes fabrication due to its highly appealing mechanical, electrical, and chemical properties . Low cost and innovative screen-printed graphene/carbon paste electrodes for electrochemical sensing of the most common electroactive analytes such as hydrogen peroxide (H2O2), nicotinamide adenine dinucleotide (NAD+), and ferric ferrocyanide (Fe(CN)63−/4−) has been established. By using Ag/AgCl paste electrodes as a reference and PVC substrates, it was found that the addition of electrolytically exfoliated graphene to the carbon-based paste greatly enhanced the electrochemical responses of the screen-printed electrodes. Due to this addition of graphene, the optimum concentration of graphene in the carbon paste was determined to be 10%, at which the most efficient cyclic voltammetry (CV) was reproduced. It was also observed that the oxidation signals for each of the compounds were increased two-fold as compared with conventional screen-printed carbon electrodes .
SPEs have been extensively used for water quality tests (Table 3), and organic compound detection in environmental samples (Table 4). SPEs for the determination of toxic heavy metals including lead (Pb2+) and cadmium (Cd2+) has been reported and the collected data is summarized in Table 5. Researchers have used a mixture of graphene (G)/polyaniline (PANI)/polyestirene (PS) electrospun nanofibers. This screen-printed G/PANI/PS electrode was successfully proven to simultaneously detect Pb2+ and Cd2+ in real river water samples through anodic stripping voltammetry (ASV). It was observed that the increased surface area improved the electrochemical response of such electrodes due to the electrospinning technique for the acquirement of nanofibers, as well as the selection and mixture of materials . The addition of graphene and other conductive elements into different materials in screen-printed electrodes has been shown to be very well applied to improvement in the detection of contaminants in the environment. It allows control monitoring of changes in the concentrations of such pollutants in various environments and therefore a more accurate treatment for such an issue .
4.2. Nanowire-Based Sensors and Environmental Contaminants
Another strategy used for increasing the surface-to-volume ratio, and thus augmenting the electrochemical sensitivity of sensors for the detection of analytes, is the implementation of nanowires for the assembly of various morphologies in electrodes. Such nanowires are often made of conductive or semiconductive materials such as gold (Au), silver (Ag), copper oxide (CuO), among others, although it depends on the analyte to be detected. Among the advantages that nanowires present over other materials are the simple preparation methods to obtain them, the surface-to-volume ratio, and high stability due to high crystallinity of such materials in their molecular structure, as well as high sensitivity and selectivity. The synthesis of nanowires can be classified into solution-phase growth and vapor-phase growth processes [119,120,121].
Copper oxide (CuO) nanowires were successfully attached to an electrochemical sensor, along with single-walled carbon nanotubes (SWCNTs) for the detection of organophosphorus pesticides used in the field of agriculture. Said electrochemical sensors composed of the aforementioned nanocomposite materials (CuO-SWCNTs), were proved to be highly stable and had good specificity towards malathion, as well as good selectivity against other pesticides, inorganic ions, and sugars. Since this work was proven in real liquid garlic samples, it demonstrates its applicability in selective detection of organophosphorus pesticides .
Nanostructured materials that include tin dioxide (SnO2) nanowires and zinc oxide (ZnO) nanorods have been designed for the sensing of gases such as ethanol, where the growth of such structures was controlled to make them perpendicular. The results revealed that the design of the hierarchical nanostructures enhanced their response to ethanol gas and the selectivity of the material for this gas, avoiding interference from gases in the environment such as ammonia (NH3), carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), and liquefied petroleum gas (LPG). These enhancements are attributed to the improvement of homogenous and heterogeneous NW–NW contacts .
5. Paper-Based Electrochemical Biosensors
In the past few years, paper has become an increasingly common substrate for developing microfluidic devices and biosensors. Several paper-based materials hold several unique characteristics, i.e., porosity, liquid wicking rate, and fiber surface affinity to numerous analytes, etc. Moreover, paper-based models offer portable, on-site, and real-time monitoring, which are crucial for applications in different sectors including clinical, nutraceutical, and environmental . Also, the broader spectrum of available supporting paper substrates, i.e., chromatography, filter, blotting, and office paper of different grades present their candidacy to engineer tunable devices and sensors and can be utilized to fulfill the requisite application . Depending on the specific application needed, the fabrication strategy and analytical techniques of paper-based sensors can be tuned to fulfill the needs of the end-user . Cinti et al.  combined the effectiveness of screen-printing with wax-printing to realize an all-in-one reagentless paper-based screen-printed electrochemical sensor to detect phosphate. They used a less-sophisticated filter paper to cover the laboratory bench and transferred the colorimetric reference method for the detection of phosphate in water directly into the paper support. A similar configuration was described by Medina-Sánchez et al.  in developing a lateral flow paper-based sensing device for lead and cadmium ions detection in environmental matrices. They screen-printed 500-µm wide electrodes, graphite ink formed the working and counter electrodes, while Ag/AgCl was printed as a reference electrode on a waxed chromatographic paper.
Sample conditions and concentrations can fluctuate over the period of sampling and transportation back to the lab. Therefore, from the environmental application viewpoint, real-time and in-process monitoring of the generation and release of environmental contaminants such as heavy toxic elements and other hazardous pollutants is essential. Electrochemical biosensors are suitable options that allow on-site detection and accurate monitoring of environmental and separation conditions [124,127]. In this context, Nie et al.  developed paper-based electrochemical biosensor device for Pb(II) ion detection. Likewise, a simple, fast, and portable paper-based dual electrochemical/colorimetric system for simultaneous determination of gold and iron has been reported . The challenge of whether to use a single drop of the solution or a stirred solution to accumulate the heavy metal was addressed by introducing a cellulose blotting pad as a sink for the outlet. This allowed continuous wicking of the solution across the electrodes which increased the efficiency and sensitivity of Pb(II) deposition during anodic stripping voltammetry . Zhang et al.  prepared a three-dimensional microfluidic paper-based analytical device for the detection of toxic heavy metals, i.e., Pb2+ and Hg2+ in one paper working zone based on the potential-control technique. Moreover, the developed paper-based analytical tool was used for simultaneous detection of Pb2+ and Hg2+ in lake water and human serum samples, respectively. Very recently, Shriver-Lake  produced a paper-based probe by impregnating a vanadium-containing polyoxometalate anion, [PMo11VO40]5− on carbon electrodes for the electrochemical determination of chlorate (Figure 6).
A multilayer paper-based device for colorimetric detection of Ni, Fe, Cu, and Cr and electrochemical detection of Pb and Cd is reported . The colorimetric layer showed lowest detection limits for Cr, i.e., 0.12 μg, while electrochemical layer was highly sensitive with Cd and Pb detection limits as low as 0.25 ng. Subject to lowest possible detection and other critical parameters, new functionalities for paper-based sensors lead to lower limits of detection, simplified user operation, fluid flow control, signal amplification, component integration and new applications along with its low cost, portability, and simplicity features have been reviewed elsewhere . Very recently, Cinti et al.  developed a fully integrated ready-to-use paper-based electrochemical biosensor for the assessment of nerve agent simulant (paraoxon) in real environmental sites. Paraoxon was linearly detected down to 3 µg/L. In this study, authors have used a carbon black/Prussian Blue nanocomposite as a working electrode modifier to improve the sensitivity of the paper-based screen-printed electrochemical biosensor device .
6. Concluding Remarks and Future Perspectives
In conclusion, it is clear from the data discussed above that the future of electrochemical biosensors will rely on the success of emerging sophisticated technologies, both at micro and nano level, along with in-depth contributions from electronics, materials science, biochemistry, and physics. The environmental pollution in different mediums is a serious health concern worldwide. Therefore, it is equally important to design and develop biosensor-based measuring techniques that can precisely detect various contaminants from a broader spectrum. However, biosensors for environmental analysis have several limitations that include (1) response time, (2) sensitivity, (3) selectivity, (4) compatibility, (5) affinity, (6) stability, and (7) lifetime, etc. These limitations should be eliminated for a successful on-site implementation as a competitive analytical tool. Besides the points mentioned above, it is also important to note whether the pollutant is gaseous (e.g., ozone, H2S, CO, O2, NOx, SOx) or whether it is confined to the solution phase. It is highly relevant to note that this type of technique in the design of such structures gives researchers the capability to experiment with the variations in the electrochemical responses of sensors with different structural arrays.
Owing to ever increasing public health concerns about the impact that environmental pollution may cause on the ecosystem, the demand for rapid detecting biosensor will increase in the near future. In spite of the past and current considerable research in electrochemical biosensor development, there is still a challenge to create improved and more reliable devices to avoid instrumental drift. In this context, in-depth study is needed to present the future trends in the biosensor field and other related areas such as bioelectronics, and bionanotechnology that will ultimately have a marked influence on the development of new bio-sensing strategies in the future. Nevertheless, the advent of “smart” and user-friendly electrochemical biosensors augers well for the future.
The literature facilities provided by Tecnologico de Monterrey, Mexico are thankfully acknowledged.
Conflicts of Interest
The authors declare no conflict of interest.
- Bilal, M.; Rasheed, T.; Sosa-Hernández, J.E.; Raza, A.; Nabeel, F.; Iqbal, H.M.N. Biosorption: An Interplay between Marine Algae and Potentially Toxic Elements—A Review. Mar. Drugs 2018, 16, 65. [Google Scholar] [CrossRef] [PubMed]
- El Harrad, L.; Bourais, I.; Mohammadi, H.; Amine, A. Recent Advances in Electrochemical Biosensors Based on Enzyme Inhibition for Clinical and Pharmaceutical Applications. Sensors 2018, 18, 164. [Google Scholar] [CrossRef] [PubMed]
- Arduini, F.; Cinti, S.; Scognamiglio, V.; Moscone, D.; Palleschi, G. How cutting-edge technologies impact the design of electrochemical (bio) sensors for environmental analysis. A review. Anal. Chim. Acta 2017, 959, 15–42. [Google Scholar] [CrossRef] [PubMed]
- Hughes, G.; Westmacott, K.; Honeychurch, K.C.; Crew, A.; Pemberton, R.M.; Hart, J.P. Recent advances in the fabrication and application of screen-printed electrochemical (bio) sensors based on carbon materials for biomedical, agri-food and environmental analyses. Biosensors 2016, 6, 50. [Google Scholar] [CrossRef] [PubMed]
- Rodriguez-Mozaz, S.; de Alda, M.J.L.; Marco, M.P.; Barceló, D. Biosensors for environmental monitoring: A global perspective. Talanta 2005. [Google Scholar] [CrossRef]
- Ronkainen, N.J.; Halsall, H.B.; Heineman, W.R. Electrochemical biosensors. Chem. Soc. Rev. 2010, 39, 1747. [Google Scholar] [CrossRef] [PubMed]
- Rasheed, T.; Bilal, M.; Nabeel, F.; Iqbal, H.M.N.; Li, C.; Zhou, Y. Fluorescent sensor based models for the detection of environmentally-related toxic heavy metals. Sci. Total Environ. 2018, 615, 476–485. [Google Scholar] [CrossRef] [PubMed]
- Barrios-Estrada, C.; de Jesús Rostro-Alanis, M.; Muñoz-Gutiérrez, B.D.; Iqbal, H.M.N.; Kannan, S.; Parra-Saldívar, R. Emergent contaminants: Endocrine disruptors and their laccase-assisted degradation—A review. Sci. Total Environ. 2018, 612, 1516–1531. [Google Scholar] [CrossRef] [PubMed]
- Ahmed, I.; Iqbal, H.M.N.; Dhama, K. Enzyme-based biodegradation of hazardous pollutants—An overview. J. Exp. Biol. Agric. Sci. 2017, 5, 402–411. [Google Scholar] [CrossRef]
- Naidu, R.; Espana, V.A.A.; Liu, Y.; Jit, J. Emerging contaminants in the environment: Risk-based analysis for better management. Chemosphere 2016, 154, 350–357. [Google Scholar] [CrossRef] [PubMed]
- Bilal, M.; Asgher, M.; Iqbal, H.M.N.; Hu, H.; Zhang, X. Bio-based degradation of emerging endocrine-disrupting and dye-based pollutants using cross-linked enzyme aggregates. Environ. Sci. Pollut. Res. 2017, 24, 7035–7041. [Google Scholar] [CrossRef] [PubMed]
- Kidd, K.A.; Blanchfield, P.J.; Mills, K.H.; Palace, V.P.; Evans, R.E.; Lazorchak, J.M.; Flick, R.W. Collapse of a fish population after exposure to a synthetic estrogen. Proc. Nat. Acad. Sci. USA 2007, 104, 8897–8901. [Google Scholar] [CrossRef] [PubMed]
- Oaks, J.L.; Gilbert, M.; Virani, M.Z.; Watson, R.T.; Meteyer, C.U.; Rideout, B.A.; Mahmood, S. Diclofenac residues as the cause of vulture population decline in Pakistan. Nature 2004, 427, 630–633. [Google Scholar] [CrossRef] [PubMed]
- Oberdörster, E.; Zhu, S.; Blickley, T.M.; McClellan-Green, P.; Haasch, M.L. Ecotoxicology of carbon-based engineered nanoparticles: Effects of fullerene (C60) on aquatic organisms. Carbon 2006, 44, 1112–1120. [Google Scholar] [CrossRef]
- Kim, S.-C.; Lee, D. Preparation of TiO2-coated hollow glass beads and their application to the control of algal growth in eutrophic water. Microchem. J. 2005, 80, 227–232. [Google Scholar] [CrossRef]
- Raghav, M.; Eden, S.; Mitchell, K.; Witte, B. Contaminants of Emerging Concern in Water. Available online: http://arizona.openrepository.com/arizona/bitstream/10150/325905/3/Arroyo_2013.pdf (accessed on 22 March 2018).
- Petrie, B.; Barden, R.; Kasprzyk-Hordern, B. A review on emerging contaminants in wastewaters and the environment: Current knowledge, understudied areas and recommendations for future monitoring. Water Res. 2015, 72, 3–27. [Google Scholar] [CrossRef] [PubMed]
- Sangion, A.; Gramatica, P. PBT assessment and prioritization of contaminants of emerging concern: Pharmaceuticals. Environ. Res. 2016, 147, 297–306. [Google Scholar] [CrossRef] [PubMed]
- Sangion, A.; Gramatica, P. Hazard of pharmaceuticals for aquatic environment: Prioritization by structural approaches and prediction of ecotoxicity. Environ. Int. 2016, 95, 131–143. [Google Scholar] [CrossRef] [PubMed]
- Hughes, S.R.; Kay, P.; Brown, L.E. Global synthesis and critical evaluation of pharmaceutical data sets collected from river systems. Environmen. Sci. Technol. 2013, 47, 661–677. [Google Scholar] [CrossRef] [PubMed]
- Ullah, S.; Zuberi, A.; Alagawany, M.; Farag, M.R.; Dadar, M.; Karthik, K.; Tiwari, R.; Dhama, K.; Iqbal, H.M.N. Cypermethrin induced toxicities in fish and adverse health outcomes: Its prevention and control measure adaptation. J. Environ. Manag. 2018, 206, 863–871. [Google Scholar] [CrossRef] [PubMed]
- Köhler, H.R.; Triebskorn, R. Wildlife ecotoxicology of pesticides: Can we track effects to the population level and beyond? Science 2013, 341, 759–765. [Google Scholar] [CrossRef] [PubMed]
- WHO. Agrochemicals, Health and Environment: Directory of Resources. 2017. Available online: http://www.who.int/heli/risks/toxics/chemicalsdirectory/en/index1.html (accessed on 24 January 2018).
- Emerging Contaminants from Industrial and Municipal Waste: Removal Technologies; Barceló, D.; Petrovic, M. (Eds.) Springer: Berlin/Heidelberg, Germay, 2008; Volume 5. [Google Scholar]
- Carvalho, F.P. Pesticides, environment, and food safety. Food Energy Secur. 2017, 6, 48–60. [Google Scholar] [CrossRef]
- Moreno-Gonzalez, R.; Leon, V.M. Presence and distribution of current-use pesticides in surface marine sediments from a Mediterranean coastal lagoon (SE Spain). Environ. Sci. Pollut. Res. Int. 2017, 24, 8033–8048. [Google Scholar] [CrossRef] [PubMed]
- Riva, F.; Castiglioni, S.; Fattore, E.; Manenti, A.; Davoli, E.; Zuccato, E. Monitoring emerging contaminants in the drinking water of milan and assessment of the human risk. Int. J. Hyg. Environ. Health 2018. [Google Scholar] [CrossRef] [PubMed]
- Petrović, M.; Gonzalez, S.; Barceló, D. Analysis and removal of emerging contaminants in wastewater and drinking water. TrAC Trend. Anal. Chem. 2003, 22, 685–696. [Google Scholar] [CrossRef]
- Richardson, S.D. Water analysis: Emerging contaminants and current issues. Anal. Chem. 2009, 81, 4645–4677. [Google Scholar] [CrossRef] [PubMed]
- Li, M.; Li, Y.T.; Li, D.W.; Long, Y.T. Recent developments and applications of screen-printed electrodes in environmental assays—A review. Anal. Chim. Acta 2012, 734, 31–44. [Google Scholar] [CrossRef] [PubMed]
- Grieshaber, D.; MacKenzie, R.; Vörös, J.; Reimhult, E. Electrochemical Biosensors-Sensor Principles and Architectures. Sensors 2008, 8, 1400–1458. [Google Scholar] [CrossRef] [PubMed]
- Buerk, D.G. Biosensors: Theory and Applications; Technomic Publish. Co. Inc.: Lancaster, UK, 1993. [Google Scholar]
- Bakker, E.; Pretsch, E. Potentiometric sensors for trace-level analysis. TrAC Trend. Anal. Chem. 2005, 243, 199–207. [Google Scholar] [CrossRef] [PubMed]
- Chang, B.-Y.; Park, S.-M. Electrochemical Impedance Spectroscopy. Ann. Rev. Anal. Chem. 2010, 3, 207–229. [Google Scholar] [CrossRef] [PubMed]
- Torsi, L.; Magliulo, M.; Manoli, K.; Palazzo, G. Organic field-effect transistor sensors: A tutorial review. Chem. Soc. Rev. 2013, 42, 8612. [Google Scholar] [CrossRef] [PubMed]
- Yamanaka, K.; Vestergaard, M.C.; Tamiya, E. Printable electrochemical biosensors: A focus on screen-printed electrodes and their application. Sensors (Switzerland) 2016, 16, 1–16. [Google Scholar] [CrossRef] [PubMed]
- Martínez-García, G.; Pérez-Julián, E.; Agüí, L.; Cabré, N.; Joven, J.; Yáñez-Sedeño, P.; Pingarrón, J.M. An Electrochemical Enzyme Biosensor for 3-Hydroxybutyrate Detection Using Screen-Printed Electrodes Modified by Reduced Graphene Oxide and Thionine. Biosensors 2017, 7, 50. [Google Scholar] [CrossRef] [PubMed]
- Vaseashta, A.; Dimova-Malinovska, D. Nanostructured and nanoscale devices, sensors and detectors. Sci. Technol. Adv. Mater. 2005, 6, 312–318. [Google Scholar] [CrossRef]
- Wanekaya, A.K.; Chen, W.; Myung, N.V.; Mulchandani, A. Nanowire-based electrochemical biosensors. Electroanalysis 2006, 18, 533–550. [Google Scholar] [CrossRef]
- Richardson, S.D.; Ternes, T.A. Water analysis: Emerging contaminants and current issues. Anal. Chem. 2011, 83, 4614–4648. [Google Scholar] [CrossRef] [PubMed]
- Kimmel, D.W.; LeBlanc, G.; Meschievitz, M.E.; Cliffel, D.E. Electrochemical sensors and biosensors. Anal. Chem. 2011, 84, 685–707. [Google Scholar] [CrossRef] [PubMed]
- Wang, J.; Myung, N.V.; Yun, M.; Monbouquette, H.G. Glucose oxidase entrapped in polypyrrole on high-surface-area Pt electrodes: A model platform for sensitive electroenzymatic biosensors. J. Electroanal. Chem. 2005, 575, 139–146. [Google Scholar] [CrossRef]
- Chai, F.; Wang, C.; Wang, T.; Li, L.; Su, Z. Colorimetric detection of Pb2+ using glutathione functionalized gold nanoparticles. ACS Appl. Mater. Interface 2010, 2, 1466–1470. [Google Scholar] [CrossRef] [PubMed]
- Gao, L.; Lian, C.; Zhou, Y.; Yan, L.; Li, Q.; Zhang, C.; Chen, K. Graphene oxide–DNA based sensors. Biosens. Bioelectron. 2014, 60, 22–29. [Google Scholar] [CrossRef] [PubMed]
- Darbha, G.K.; Singh, A.K.; Rai, U.S.; Yu, E.; Yu, H.; Chandra Ray, P. Selective detection of mercury (II) ion using nonlinear optical properties of gold nanoparticles. J. Am. Chem. Soc. 2008, 130, 8038–8043. [Google Scholar] [CrossRef] [PubMed]
- Darbha, G.K.; Ray, A.; Ray, P.C. 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, 208–214. [Google Scholar] [CrossRef] [PubMed]
- Huang, C.C.; Yang, Z.; Lee, K.H.; Chang, H.T. Synthesis of highly fluorescent gold nanoparticles for sensing mercury (II). Angew. Chem. 2007, 119, 6948–6952. [Google Scholar] [CrossRef]
- Chang, J.; Huang, X.; Zhou, G.; Cui, S.; Hallac, P.B.; Jiang, J.; Chen, J. Multilayered Si Nanoparticle/Reduced Graphene Oxide Hybrid as a High-Performance Lithium-Ion Battery Anode. Adv. Mater. 2014, 26, 758–764. [Google Scholar] [CrossRef] [PubMed]
- Chen, K.; Lu, G.; Chang, J.; Mao, S.; Yu, K.; Cui, S.; Chen, J. Hg (II) ion detection using thermally reduced graphene oxide decorated with functionalized gold nanoparticles. Anal. Chem. 2012, 84, 4057–4062. [Google Scholar] [CrossRef] [PubMed]
- Sudibya, H.G.; He, Q.; Zhang, H.; Chen, P. Electrical detection of metal ions using field-effect transistors based on micropatterned reduced graphene oxide films. ACS Nano 2011, 5, 1990–1994. [Google Scholar] [CrossRef] [PubMed]
- Kim, T.H.; Lee, J.; Hong, S. Highly selective environmental nanosensors based on anomalous response of carbon nanotube conductance to mercury ions. J. Phys. Chem. C 2009, 113, 19393–19396. [Google Scholar] [CrossRef]
- Chouteau, C.; Dzyadevych, S.; Durrieu, C.; Chovelon, J.M. A bi-enzymatic whole cell conductometric biosensor for heavy metal ions and pesticides detection in water samples. Biosens. Bioelectron. 2005, 21, 273–281. [Google Scholar] [CrossRef] [PubMed]
- Bi, X.; Agarwal, A.; Yang, K.L. Oligopeptide-modified silicon nanowire arrays as multichannel metal ion sensors. Biosens. Bioelectron. 2009, 24, 3248–3251. [Google Scholar] [CrossRef] [PubMed]
- So, H.M.; Park, D.W.; Jeon, E.K.; Kim, Y.H.; Kim, B.S.; Lee, C.K.; Lee, J.O. Detection and Titer Estimation of Escherichia coli Using Aptamer-Functionalized Single-Walled Carbon-Nanotube Field-Effect Transistors. Small 2008, 4, 197–201. [Google Scholar] [CrossRef] [PubMed]
- Huang, Y.; Dong, X.; Liu, Y.; Li, L.J.; Chen, P. Graphene-based biosensors for detection of bacteria and their metabolic activities. J. Mater. Chem. 2011, 21, 12358–12362. [Google Scholar] [CrossRef]
- Chen, Y.; Michael, Z.P.; Kotchey, G.P.; Zhao, Y.; Star, A. Electronic detection of bacteria using holey reduced graphene oxide. ACS Appl. Mater. Interface 2014, 6, 3805–3810. [Google Scholar] [CrossRef] [PubMed]
- Kumar Jena, B.; Retna Raj, C. Gold nanoelectrode ensembles for the simultaneous electrochemical detection of ultratrace arsenic, mercury, and copper. Anal. Chem. 2008, 80, 4836–4844. [Google Scholar] [CrossRef] [PubMed]
- Gong, J.; Zhou, T.; Song, D.; Zhang, L.; Hu, X. Stripping voltammetric detection of mercury (II) based on a bimetallic Au-Pt inorganic-organic hybrid nanocomposite modified glassy carbon electrode. Anal. Chem. 2009, 82, 567–573. [Google Scholar] [CrossRef] [PubMed]
- Xu, H.; Zeng, L.; Xing, S.; Xian, Y.; Shi, G.; Jin, L. Ultrasensitive voltammetric detection of trace lead (II) and cadmium (II) using MWCNTs-nafion/bismuth composite electrodes. Electroanalysis 2008, 20, 2655–2662. [Google Scholar] [CrossRef]
- Aragay, G.; Pons, J.; Merkoçi, A. Recent trends in macro-, micro-, and nanomaterial-based tools and strategies for heavy-metal detection. Chem. Rev. 2011, 111, 3433–3458. [Google Scholar] [CrossRef] [PubMed]
- Injang, U.; Noyrod, P.; Siangproh, W.; Dungchai, W.; Motomizu, S.; Chailapakul, O. Determination of trace heavy metals in herbs by sequential injection analysis-anodic stripping voltammetry using screen-printed carbon nanotubes electrodes. Anal. Chim. Acta 2010, 668, 54–60. [Google Scholar] [CrossRef] [PubMed]
- Hwang, G.H.; Han, W.K.; Park, J.S.; Kang, S.G. Determination of trace metals by anodic stripping voltammetry using a bismuth-modified carbon nanotube electrode. Talanta 2008, 76, 301–308. [Google Scholar] [CrossRef] [PubMed]
- Xu, R.X.; Yu, X.Y.; Gao, C.; Jiang, Y.J.; Han, D.D.; Liu, J.H.; Huang, X.J. Non-conductive nanomaterial enhanced electrochemical response in stripping voltammetry: The use of nanostructured magnesium silicate hollow spheres for heavy metal ions detection. Anal. Chim. Acta 2013, 790, 31–38. [Google Scholar] [CrossRef] [PubMed]
- Zhu, H.; Xu, Y.; Liu, A.; Kong, N.; Shan, F.; Yang, W.; Liu, J. Graphene nanodots-encaged porous gold electrode fabricated via ion beam sputtering deposition for electrochemical analysis of heavy metal ions. Sens. Actuators B Chem. 2015, 206, 592–600. [Google Scholar] [CrossRef]
- Huang, H.; Chen, T.; Liu, X.; Ma, H. Ultrasensitive and simultaneous detection of heavy metal ions based on three-dimensional graphene-carbon nanotubes hybrid electrode materials. Anal. Chim. Acta 2014, 852, 45–54. [Google Scholar] [CrossRef] [PubMed]
- Li, J.; Guo, S.; Zhai, Y.; Wang, E. High-sensitivity determination of lead and cadmium based on the Nafion-graphene composite film. Anal. Chim. Acta 2009, 649, 196–201. [Google Scholar] [CrossRef] [PubMed]
- Gao, C.; Yu, X.Y.; Xiong, S.Q.; Liu, J.H.; Huang, X.J. Electrochemical detection of arsenic (III) completely free from noble metal: Fe3O4 microspheres-room temperature ionic liquid composite showing better performance than gold. Anal. Chem. 2013, 85, 2673–2680. [Google Scholar] [CrossRef] [PubMed]
- Pan, D.; Wang, Y.; Chen, Z.; Lou, T.; Qin, W. Nanomaterial/ionophore-based electrode for anodic stripping voltammetric determination of lead: An electrochemical sensing platform toward heavy metals. Anal. Chem. 2009, 81, 5088–5094. [Google Scholar] [CrossRef] [PubMed]
- Zou, Z.; Han, J.; Jang, A.; Bishop, P.L.; Ahn, C.H. A disposable on-chip phosphate sensor with planar cobalt microelectrodes on polymer substrate. Biosens. Bioelectron. 2007, 22, 1902–1907. [Google Scholar] [CrossRef] [PubMed]
- Apetrei, C.; Apetrei, I.M.; Saja, J.A.D.; Rodriguez-Mendez, M.L. Carbon paste electrodes made from different carbonaceous materials: Application in the study of antioxidants. Sensors 2011, 11, 1328–1344. [Google Scholar] [CrossRef] [PubMed]
- Güell, A.G.; Meadows, K.E.; Unwin, P.R.; Macpherson, J.V. Trace voltammetric detection of serotonin at carbon electrodes: Comparison of glassy carbon, boron doped diamond and carbon nanotube network electrodes. Phys. Chem. Chem. Phys. 2010, 12, 10108–10114. [Google Scholar]
- Raccichini, R.; Varzi, A.; Passerini, S.; Scrosati, B. The role of graphene for electrochemical energy storage. Nat. Mater. 2015, 14, 271–279. [Google Scholar] [CrossRef] [PubMed]
- Karuwan, C.; Wisitsoraat, A.; Phokharatkul, D.; Sriprachuabwong, C.; Lomas, T.; Nacapricha, D.; Tuantranont, A. A disposable screen printed graphene–carbon paste electrode and its application in electrochemical sensing. RSC Adv. 2013, 3, 25792–25799. [Google Scholar] [CrossRef]
- Promphet, N.; Rattanarat, P.; Rangkupan, R.; Chailapakul, O.; Rodthongkum, N. An electrochemical sensor based on graphene/polyaniline/polystyrene nanoporous fibers modified electrode for simultaneous determination of lead and cadmium. Sens. Actuators B Chem. 2015, 207, 526–534. [Google Scholar] [CrossRef]
- Hayat, A.; Marty, J.L. Disposable screen printed electrochemical sensors: Tools for environmental monitoring. Sensors 2014, 14, 10432–10453. [Google Scholar] [CrossRef] [PubMed]
- Müller, A.; Brinz, T.; Simon, U. Preparation and measurement of combinatorial screen printed libraries for the electrochemical analysis of liquids. J. Comb. Chem. 2008, 11, 138–142. [Google Scholar] [CrossRef] [PubMed]
- Kampouris, D.K.; Kadara, R.O.; Jenkinson, N.; Banks, C.E. Screen printed electrochemical platforms for pH sensing. Anal. Methods 2009, 1, 25–28. [Google Scholar] [CrossRef]
- Hallam, P.M.; Kampouris, D.K.; Kadara, R.O.; Jenkinson, N.; Banks, C.E. Nickel oxide screen printed electrodes for the sensing of hydroxide ions in aqueous solutions. Anal. Methods 2010, 2, 1152–1155. [Google Scholar] [CrossRef]
- Zheng, R.J.; Fang, Y.M.; Qin, S.F.; Song, J.; Wu, A.H.; Sun, J.J. A dissolved oxygen sensor based on hot electron induced cathodic electrochemiluminescence at a disposable CdS modified screen-printed carbon electrode. Sens. Actuators B Chem. 2011, 157, 488–493. [Google Scholar] [CrossRef]
- Chang, J.L.; Zen, J.M. A poly (dimethylsiloxane)-based electrochemical cell coupled with disposable screen printed edge band ultramicroelectrodes for use in flow injection analysis. Electrochem. Commun. 2007, 9, 2744–2750. [Google Scholar] [CrossRef]
- Khairy, M.; Kadara, R.O.; Banks, C.E. Electroanalytical sensing of nitrite at shallow recessed screen printed microelectrode arrays. Anal. Methods 2010, 2, 851–854. [Google Scholar] [CrossRef]
- Khaled, E.; Hassan, H.N.A.; Girgis, A.; Metelka, R. Construction of novel simple phosphate screen-printed and carbon paste ion-selective electrodes. Talanta 2008, 77, 737–743. [Google Scholar] [CrossRef]
- Gilbert, L.; Jenkins, A.T.; Browning, S.; Hart, J.P. Development of an amperometric assay for phosphate ions in urine based on a chemically modified screen-printed carbon electrode. Anal. Biochem. 2009, 393, 242–247. [Google Scholar] [CrossRef] [PubMed]
- Gilbert, L.; Jenkins, A.T.A.; Browning, S.; Hart, J.P. Development of an amperometric, screen-printed, single-enzyme phosphate ion biosensor and its application to the analysis of biomedical and environmental samples. Sens. Actuators B Chem. 2011, 160, 1322–1327. [Google Scholar] [CrossRef]
- Karousos, N.; Chong, L.C.; Ewen, C.; Livingstone, C.; Davis, J. Evaluation of a multifunctional indicator for the electroanalytical determination of nitrite. Electrochim. Acta 2005, 50, 1879–1884. [Google Scholar] [CrossRef]
- Quan, D.; Shim, J.H.; Kim, J.D.; Park, H.S.; Cha, G.S.; Nam, H. Electrochemical determination of nitrate with nitrate reductase-immobilized electrodes under ambient air. Anal. Chem. 2005, 77, 4467–4473. [Google Scholar] [CrossRef] [PubMed]
- Plumeré, N.; Henig, J.; Campbell, W.H. Enzyme-catalyzed O2 removal system for electrochemical analysis under ambient air: Application in an amperometric nitrate biosensor. Anal. Chem. 2012, 84, 2141–2146. [Google Scholar] [CrossRef] [PubMed]
- Won, Y.H.; Jang, H.S.; Kim, S.M.; Stach, E.; Ganesana, M.; Andreescu, S.; Stanciu, L.A. Biomagnetic glasses: Preparation, characterization, and biosensor applications. Langmuir 2009, 26, 4320–4326. [Google Scholar] [CrossRef] [PubMed]
- Crew, A.; Lonsdale, D.; Byrd, N.; Pittson, R.; Hart, J.P. A screen-printed, amperometric biosensor array incorporated into a novel automated system for the simultaneous determination of organophosphate pesticides. Biosens. Bioelectron. 2011, 26, 2847–2851. [Google Scholar] [CrossRef] [PubMed]
- Arduini, F.; Guidone, S.; Amine, A.; Palleschi, G.; Moscone, D. Acetylcholinesterase biosensor based on self-assembled monolayer-modified gold-screen printed electrodes for organophosphorus insecticide detection. Sen. Actuators B Chem. 2013, 179, 201–208. [Google Scholar] [CrossRef]
- Alonso, G.A.; Muñoz, R.; Marty, J.L. Automatic electronic tongue for on-line detection and quantification of organophosphorus and carbamate pesticides using enzymatic screen printed biosensors. Anal. Lett. 2013, 46, 1743–1757. [Google Scholar] [CrossRef]
- Su, W.Y.; Wang, S.M.; Cheng, S.H. Electrochemically pretreated screen-printed carbon electrodes for the simultaneous determination of aminophenol isomers. J. Electroanal. Chem. 2011, 651, 166–172. [Google Scholar] [CrossRef]
- Baskeyfield, D.E.; Davis, F.; Magan, N.; Tothill, I.E. A membrane-based immunosensor for the analysis of the herbicide isoproturon. Anal. Chim. Acta 2011, 699, 223–231. [Google Scholar] [CrossRef] [PubMed]
- Bhalla, V.; Zazubovich, V. Self-assembly and sensor response of photosynthetic reaction centers on screen-printed electrodes. Anal. Chim. Acta 2011, 707, 184–190. [Google Scholar] [CrossRef] [PubMed]
- Ivanov, A.N.; Younusov, R.R.; Evtugyn, G.A.; Arduini, F.; Moscone, D.; Palleschi, G. Acetylcholinesterase biosensor based on single-walled carbon nanotubes—Co. phtalocyanine for organophosphorus pesticides detection. Talanta 2011, 85, 216–221. [Google Scholar] [CrossRef] [PubMed]
- Li, H.; Li, J.; Yang, Z.; Xu, Q.; Hu, X. A novel photoelectrochemical sensor for the organophosphorus pesticide dichlofenthion based on nanometer-sized titania coupled with a screen-printed electrode. Anal. Chem. 2011, 83, 5290–5295. [Google Scholar] [CrossRef] [PubMed]
- Mayorga-Martinez, C.C.; Cadevall, M.; Guix, M.; Ros, J.; Merkoçi, A. Bismuth nanoparticles for phenolic compounds biosensing application. Biosens. Bioelectron. 2013, 40, 57–62. [Google Scholar] [CrossRef] [PubMed]
- Mayorga-Martinez, C.C.; Pino, F.; Kurbanoglu, S.; Rivas, L.; Ozkan, S.A.; Merkoçi, A. Iridium oxide nanoparticle induced dual catalytic/inhibition based detection of phenol and pesticide compounds. J. Mater. Chem. B 2014, 2, 2233–2239. [Google Scholar] [CrossRef]
- Nadifiyine, S.; Haddam, M.; Mandli, J.; Chadel, S.; Blanchard, C.C.; Marty, J.L.; Amine, A. Amperometric Biosensor Based on Tyrosinase Immobilized on to a Carbon Black Paste Electrode for Phenol Determination in Olive Oil. Anal. Lett. 2013, 46, 2705–2726. [Google Scholar] [CrossRef]
- Lu, L.; Zhang, L.; Zhang, X.; Huan, S.; Shen, G.; Yu, R. A novel tyrosinase biosensor based on hydroxyapatite–chitosan nanocomposite for the detection of phenolic compounds. Anal. Chim. Acta 2010, 665, 146–151. [Google Scholar] [CrossRef] [PubMed]
- Maczuga, M.; Economou, A.; Bobrowski, A.; Prodromidis, M.I. Novel screen-printed antimony and tin voltammetric sensors for anodic stripping detection of Pb (II) and Cd (II). Electrochim. Acta 2013, 114, 758–765. [Google Scholar] [CrossRef]
- Andreuccetti, C.; Bettazzi, F.; Giorgi, C.; Laschi, S.; Marrazza, G.; Mascini, M.; Palchetti, I. Macrocyclic Polyamine Modified Screen-Printed Electrodes for Copper (II) Detection. In Sensors; Springer: New York, NY, USA, 2014; pp. 471–474. [Google Scholar]
- Bouden, S.; Bellakhal, N.; Chaussé, A.; Vautrin-Ul, C. Performances of carbon-based screen-printed electrodes modified by diazonium salts with various carboxylic functions for trace metal sensors. Electrochem. Commun. 2014, 41, 68–71. [Google Scholar] [CrossRef]
- Chen, C.; Niu, X.; Chai, Y.; Zhao, H.; Lan, M. Bismuth-based porous screen-printed carbon electrode with enhanced sensitivity for trace heavy metal detection by stripping voltammetry. Sens. Actuators B Chem. 2013, 178, 339–342. [Google Scholar] [CrossRef]
- Jian, J.M.; Liu, Y.Y.; Zhang, Y.L.; Guo, X.S.; Cai, Q. Fast and sensitive detection of Pb2+ in foods using disposable screen-printed electrode modified by reduced graphene oxide. Sensors 2013, 13, 13063–13075. [Google Scholar] [CrossRef] [PubMed]
- Fu, L.; Li, X.; Yu, J.; Ye, J. Facile and Simultaneous Stripping Determination of Zinc, Cadmium and Lead on Disposable Multiwalled Carbon Nanotubes Modified Screen-Printed Electrode. Electroanalysis 2013, 25, 567–572. [Google Scholar] [CrossRef]
- Wei, Y.; Yang, R.; Liu, J.H.; Huang, X.J. Selective detection toward Hg (II) and Pb (II) using polypyrrole/carbonaceous nanospheres modified screen-printed electrode. Electrochim. Acta 2013, 105, 218–223. [Google Scholar] [CrossRef]
- Gich, M.; Fernández-Sánchez, C.; Cotet, L.C.; Niu, P.; Roig, A. Facile synthesis of porous bismuth–carbon nanocomposites for the sensitive detection of heavy metals. J. Mater. Chem. A 2013, 1, 11410–11418. [Google Scholar] [CrossRef]
- Chen, C.; Niu, X.; Chai, Y.; Zhao, H.; Lan, M.; Zhu, Y.; Wei, G. Determination of Lead (II) Using Screen-Printed Bismuth-Antimony Film Electrode. Electroanalysis 2013, 25, 1446–1452. [Google Scholar] [CrossRef]
- Bouden, S.; Chaussé, A.; Dorbes, S.; El Tall, O.; Bellakhal, N.; Dachraoui, M.; Vautrin-Ul, C. Trace lead analysis based on carbon-screen-printed-electrodes modified via 4-carboxy-phenyl diazonium salt electroreduction. Talanta 2013, 106, 414–421. [Google Scholar] [CrossRef] [PubMed]
- Punrat, E.; Chuanuwatanakul, S.; Kaneta, T.; Motomizu, S.; Chailapakul, O. Method development for the determination of arsenic by sequential injection/anodic stripping voltammetry using long-lasting gold-modified screen-printed carbon electrode. Talanta 2013, 116, 1018–1025. [Google Scholar] [CrossRef] [PubMed]
- Khairy, M.; Kampouris, D.K.; Kadara, R.O.; Banks, C.E. Gold nanoparticle modified screen printed electrodes for the trace sensing of arsenic (III) in the presence of copper (II). Electroanalysis 2010, 22, 2496–2501. [Google Scholar] [CrossRef]
- Sanllorente-Méndez, S.; Domínguez-Renedo, O.; Arcos-Martínez, M.J. Immobilization of acetylcholinesterase on screen-printed electrodes. Application to the determination of arsenic (III). Sensors 2010, 10, 2119–2128. [Google Scholar] [CrossRef] [PubMed]
- Aragay, G.; Pons, J.; Merkoçi, A. Enhanced electrochemical detection of heavy metals at heated graphite nanoparticle-based screen-printed electrodes. J. Mater. Chem. 2011, 21, 4326–4331. [Google Scholar] [CrossRef]
- Bernalte, E.; Sánchez, C.M.; Gil, E.P. Gold nanoparticles-modified screen-printed carbon electrodes for anodic stripping voltammetric determination of mercury in ambient water samples. Sens. Actuators B Chem. 2012, 161, 669–674. [Google Scholar] [CrossRef]
- Song, W.; Zhang, L.; Shi, L.; Li, D.W.; Li, Y.; Long, Y.T. Simultaneous determination of cadmium (II), lead (II) and copper (II) by using a screen-printed electrode modified with mercury nano-droplets. Microchim. Acta 2010, 169, 321–326. [Google Scholar] [CrossRef]
- Fang, H.L.; Zheng, H.X.; Ou, M.Y.; Meng, Q.; Fan, D.H.; Wang, W. One-step sensing lead in surface waters with screen printed electrode. Sens. Actuators B Chem. 2011, 153, 369–372. [Google Scholar] [CrossRef]
- Henríquez, C.; Laglera, L.M.; Alpizar, M.J.; Calvo, J.; Arduini, F.; Cerdà, V. Cadmium determination in natural water samples with an automatic multisyringe flow injection system coupled to a flow-through screen printed electrode. Talanta 2012, 96, 140–146. [Google Scholar] [CrossRef] [PubMed]
- Guo, S.; Wen, D.; Dong, S.; Wang, E. Gold nanowire assembling architecture for H2O2 electrochemical sensor. Talanta 2009, 77, 1510–1517. [Google Scholar] [CrossRef] [PubMed]
- Ramgir, N.S.; Yang, Y.; Zacharias, M. Nanowire-Based Sensors. Small 2010, 6, 1705–1722. [Google Scholar] [CrossRef] [PubMed]
- Govindhan, M.; Adhikari, B.R.; Chen, A. Nanomaterials-based electrochemical detection of chemical contaminants. RSC Adv. 2014, 4, 63741–63760. [Google Scholar] [CrossRef]
- Huo, D.; Li, Q.; Zhang, Y.; Hou, C.; Lei, Y. A highly efficient organophosphorus pesticides sensor based on CuO nanowires–SWCNTs hybrid nanocomposite. Sens. Actuators B Chem. 2014, 199, 410–417. [Google Scholar] [CrossRef]
- Khoang, N.D.; Van Duy, N.; Hoa, N.D.; Van Hieu, N. Design of SnO 2/ZnO hierarchical nanostructures for enhanced ethanol gas-sensing performance. Sens. Actuators B Chem. 2012, 174, 594–601. [Google Scholar] [CrossRef]
- Liana, D.D.; Raguse, B.; Gooding, J.J.; Chow, E. Recent advances in paper-based sensors. Sensors 2012, 12, 11505–11526. [Google Scholar] [CrossRef] [PubMed]
- Cinti, S.; Talarico, D.; Palleschi, G.; Moscone, D.; Arduini, F. Novel reagentless paper-based screen-printed electrochemical sensor to detect phosphate. Anal. Chim. Acta 2016, 919, 78–84. [Google Scholar] [CrossRef] [PubMed]
- Medina-Sánchez, M.; Cadevall, M.; Ros, J.; Merkoçi, A. Eco-friendly electrochemical lab-on-paper for heavy metal detection. Anal. Bioanal. Chem. 2015, 407, 8445–8449. [Google Scholar] [CrossRef] [PubMed]
- Carvalhal, R.F.; Carrilho, E.; Kubota, L.T. The potential and application of microfluidic paper-based separation devices. Bioanalysis 2010, 2, 1663–1665. [Google Scholar] [CrossRef] [PubMed]
- Nie, Z.H.; Nijhuis, C.A.; Gong, J.L.; Chen, X.; Kumachev, A.; Martinez, A.W.; Narovlyansky, M.; Whitesides, G.M. Electrochemical sensing in paper-based microfluidic devices. Lab Chip 2010, 10, 477–483. [Google Scholar] [CrossRef] [PubMed]
- Apilux, A.; Dungchai, W.; Siangproh, W.; Praphairaksit, N.; Henry, C.S.; Chailapakul, O. Lab-on-paper with dual electrochemical/colorimetric detection for simultaneous determination of gold and iron. Anal. Chem. 2010, 82, 1727–1732. [Google Scholar] [CrossRef] [PubMed]
- Zhang, M.; Ge, L.; Ge, S.; Yan, M.; Yu, J.; Huang, J.; Liu, S. Three-dimensional paper-based electrochemiluminescence device for simultaneous detection of Pb2+ and Hg2+ based on potential-control technique. Biosens. Bioelectron. 2013, 41, 544–550. [Google Scholar] [CrossRef] [PubMed]
- Shriver-Lake, L.C.; Zabetakis, D.; Dressick, W.J.; Stenger, D.A.; Trammell, S.A. Based Electrochemical Detection of Chlorate. Sensors 2018, 18, 328. [Google Scholar] [CrossRef] [PubMed]
- Rattanarat, P.; Dungchai, W.; Cate, D.; Volckens, J.; Chailapakul, O.; Henry, C.S. Multilayer paper-based device for colorimetric and electrochemical quantification of metals. Anal. Chem. 2014, 86, 3555–3562. [Google Scholar] [CrossRef] [PubMed]
- Cunningham, J.C.; DeGregory, P.R.; Crooks, R.M. New functionalities for paper-based sensors lead to simplified user operation, lower limits of detection, and new applications. Ann. Rev. Anal. Chem. 2016, 9, 183–202. [Google Scholar] [CrossRef] [PubMed]
- Cinti, S.; Minotti, C.; Moscone, D.; Palleschi, G.; Arduini, F. Fully integrated ready-to-use paper-based electrochemical biosensor to detect nerve agents. Biosens. Bioelectron. 2017, 93, 46–51. [Google Scholar] [CrossRef] [PubMed]
Figure 1. Scheme of an electrochemical biosensor. Biological sensing elements are coupled to electrodes. These traduce the signal to deliver a readable output.
Figure 2. Four different classes and sub-classes of biosensors based on the type of transducer.
Figure 3. The neurotoxicity and other major consequences of CYP (Reproduced from Ref.  with permission from Elsevier).
Figure 4. Environmental applications of SPEs and nanowire-based biosensors.
Figure 5. Scheme of the steps involved in the preparation and functioning of the 3-hydroxybutyrate dehydrogenase (3-HBDH)/thionine (THI)/reduced graphene oxide (rGO)/screen-printed carbon electrode (SPCE) biosensor. (Reproduced from Ref. , an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)).
Table 1. Examples of EC categories derived from pharmaceutical compounds and pesticides, detection techniques, and associated effects on human health and the environment.
|Source||Examples of Main ECs||Distribution||Adverse Effects||Other detection Techniques||Reference|
|Pharmaceutical compounds||Fluoxetine (Prozac), Carbamazepine, Diphenhydramine Tetracycline, Erythromycin|
|Groundwater, surface water, wastewater treatment plant effluent, land applied biosolids, potable water, and recycled water.||Increased cancer rates, organ damage, Endocrine disruption, Antibiotic resistance in disease|
Other Unknown health effects
|Liquid chromatography coupled with mass spectrometry|
|Pesticides||Organochlorine, Carbon-14 (14C)-labeled compounds, Organophosphorus, Pyrethroids, Carbamates, Triazines||Agricultural soil, groundwater, surface water, potable water, recycled water.||Damage to biodiversity and ecosystems health by the attack of non-target organisms, environmental persistence, pest resistance,|
|Liquid chromatography coupled to mass spectrometry||[16,25,28,29]|
Table 2. Optical biosensors and electrochemical biosensors used for rapid water contaminants e.g., toxic heavy elements detection.
|Sensing material||Contaminant||LOD||Working Range||Detection Time||Reference|
|Au NP||Pb2+||3 nM||3 nM to 1 μM||6 min|||
|Au NP||Pb2+||100 nM||0.1–50 μM||25 min|||
|GO QD||Pb2+||0.09 nM||0.1–1000 nM||20 min|||
|Au NP||Hg2+||1 nM||1 nM to 1 mM||15 min|||
|Au NP||Hg2+||9.9 nM||9.9–600 nM||10 min|||
|Au NP||Hg2+||5 nM||50 nM to 10 μM||10 min|||
|Au NP/RGO||Pb2+||10 nM||10 nM to 10 μM||few seconds|||
|Au NP/RGO||Hg2+||25 nM||25 nM to 14.2 μM||few seconds|||
|RGO||Hg2+||1 nM||1–28 nM||tens of seconds|||
|SWCNT (no probe)||Hg2+||10 nM||10 nM to 1 mM||few seconds|||
|CNT||Cd2+||88 nM||88 nM to 8.8 μM||30 min|||
|SiNW||Pb2+||1 nM||1–104 nM||few seconds|||
|SWCNT||E. coli DH5a||3 × 103 CFU mL−1||3 × 103–1 × 106 CFU mL−1||20 min|||
|Graphene||E. coli K12||10 CFU mL−1||10–105 CFU mL−1||30 min|||
|RGO||E. coli O157:H7||803 CFU mL−1||803–107 CFU mL−1||25 min|||
|Au||As3+ (1 M HCl)||0.26 nM||0.26–195 nM||100 s|||
|Au–Pt NP||Hg2+ (1 M HCl)||0.04 nM||0.04–10 nM||100 s|||
|Au NP/CNT||Hg2+ (0.1 M HClO4)||0.3 nM||0.5 nM to 1.25 μM||2 min|||
|Carbon NP||Hg2+ (1 M HCl)||4.95 nM||4.95–49.5 nM||2 min|||
|CNT||Pb2+ (1 M HCl)||0.96 nM||9.6–480 nM||180 s|||
|Bi–CNT||Pb2+ (0.1 M acetate buffer)||6.24 nM||9.6–480 nM||300 s|||
|MgSiO3||Pb2+ (0.1 M NaAc–HAc)||0.247 nM||0.1–1.0 μM||tenths of seconds|||
|Graphene nanodots||Cu2+ (ammonium acetate solution)||9 nM||9 nM to 4 μM||15 min|||
|MWCNT/GO||Pb2+ (0.1 M NaAc–HAc)||0.96 nM||0.96–144 nM||3 min|||
|Graphene/nafion||Pb2+ (0.1 M acetate buffer)||0.096 nM||2.4–240 nM||300 s|||
|Fe3O4/RTIL||As3+ (acetate buffer)||0.01 nM||13.3–133 nM||few min|||
|Nanosized hydroxyapatite||Pb2+ (0.2 M HAc-NaAc)||1 nM||5.0 nM to 0.8 μM||10 min|||
|Nanosized Co.||H2PO4− (KH2PO4 solution)||10−5 to 10−2 M||1 min or less|||
Table 3. Some of the recently developed screen-printed sensors for water quality tests.
|Liquids||Iridium and ruthenium oxide||pH sensor|||
|Liquids||Phenanthraquinone moiety||pH sensor|||
|Hydroxide ions||Nickel oxide bulk||pH sensor|||
|Dissolved oxygen||CdS modified||Cathodic electrochemiluminescence|||
|Nitrite||Shallow recessed unmodified||Amperometric detection|||
|Phosphate||Bisthiourea ionophores||Amperometric detection|||
|Nitrite||Carbon Black||Multi-electrochemical methods|||
|Phosphate||Electrocatalyst cobalt phthalocyanine||Amperometric|||
|Nitrate||Modified screen printed electrodes||Electrochemical detection|||
|Nitrate||polymer (poly(vinyl alcohol)) modified||Amperometric|||
|Nitrate||commercial screen-printed electrochemical cell||Amperometric|||
Table 4. Examples of the some of the recently developed screen-printed sensors for organic compounds detection in environmental samples.
|Organophosphate pesticides||Cobalt phthalocyanine||Chronoamperometry|||
|Organophosphorus||Cysteamine self-assembled monolayer||Amperometric|||
|Organophosphorus and Carbamate Pesticides||Unmodified||Amperometry, flow system|||
|Aminophenol isomers||Untreated SPCE||Voltammetric|||
|Organophosphorus Pesticide||Single-walled carbon nanotubes—Co. phthalocyanine||Amperometry|||
|Organophosphorus Pesticide Dichlofenthion||Nanometer-Sized Titania||Photoelectrochemical|||
|Picric acid and atrazine||Self-assembled monolayer||Photo-electrochemical|||
|Chlorsulfuron||Gold (Au) metal ions||Stripping voltammetry|||
|Phenol and catechol||Bismuth nanoparticles||Amperometric measurements|||
|Phenol and pesticide||Iridium oxide nanoparticles||Electrochemical measurement|||
|Phenol||Carbon Black Paste||Amperometric|||
|Phenolic compounds||Nano-HA-chitosan nanocomposite-modified gold electrode||Amperometric|||
Table 5. Selected and recently developed screen-printed sensors for heavy metal detections.
|Pb2+ and Cd2+||screen-printed antimony and tin||anodic stripping detection|||
|Cu2+||Macrocyclic Polyamine Modified Screen-Printed Electrodes||Square wave anodic stripping voltammetry|||
|Cd2+, Cu2+||Diazonium modified electtrodes||Amperometric detection|||
|Pb2+ and Cd2+||Bismuth-coated||Stripping voltammetry|||
|Pb2+||Reduced graphene oxide||Square wave anodic stripping voltammetry|||
|Zn2+, Cd2+ and Pb2+||Multiwalled carbon nanotubes||Differential pulse stripping voltammetry|||
|Hg2+ and Pb2+||Polypyrrole/carbonaceous nanospheres||Square wave anodic stripping voltammetry|||
|Pb2+ and Cd2+||Bismuth–carbon nanocomposites||Differential electrochemical methods|||
|Pb2+||Bismuth-antimony film||Stripping voltammetric|||
|Pb2+||4-carboxyphenyl-grafted||Anodic Square Wave Voltammetry|||
|As(III)||Gold electrode||Sequential injection/anodic stripping voltammetry|||
|As(III)||Nanoparticles||Linear sweep voltammetric|||
|As(III)||Modified screen printed electrodes||Amperometric|||
|Cd2+, Pb2+, Cu2+ and Hg2+ ions||Heated graphitenanoparticle||Electrochemical stripping|||
|Hg2+||Gold nanoparticles-modified||Square wave anodic stripping voltammetry|||
|Pb2+, Cu2+ and Cd2+||Mercury nano-droplets||Square wave anodic stripping voltammetry|||
|Pb2+||Paper disk impregnated||One-step electrochemical detection|||
|Cd2+||Nafion. Cd||Square Wave Anodic Stripping Voltammetry|||
© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).