Can biosensors detect contaminants in aqueous medium by impedance spectroscopy?

doi:10.15406/ijbsbe.2019.05.00152

International Journal of

eISSN: 2573-2838

Biosensors & Bioelectronics

Mini Review Volume 5 Issue 2

Can biosensors detect contaminants in aqueous medium by impedance spectroscopy?

Pedro Bertemes Filho,

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John Alexander Gómez-Sánchez

Department of Electrical Engineering, Universidade do Estado de Santa Catarina (UDESC), Brazil

Correspondence: Pedro Bertemes Filho, Department of Electrical Engineering, Universidade do Estado de Santa Catarina (UDESC), Rua Paulo Malschitzki, 200 Zona Industrial Norte, Joinville / SC CEP: 89.219-710, Brazil, Tel +55 47 40097981

Received: March 22, 2019 | Published: April 22, 2019

Citation: Filho PB, Gómez-Sánchez JA. Can biosensors detect contaminants in aqueous medium by impedance spectroscopy? Int J Biosen Bioelectron. 2019;5(2):45-46. DOI: 10.15406/ijbsbe.2019.05.00152

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Abstract

Biosensors are powerful tools for environmental, human and animal health monitoring. The development of portable devices based on electrical impedance spectroscopy together with specific biosensors may allow the realization of in situ measurements to determine contaminants in water. As a result, quick and well-informed decisions can be made for the benefit of the communities.

Background

The development of biosensors based on physicochemical sensors has taken a significant step forward since 1960. These devices are used to measure physical variables in biological, industrial, and human processes. The main characteristic of biosensor is biological recognition of elements by using nanomaterials and biomimetic materials. The biosensor has high sensitivity and detection mechanisms through optical, electrical and piezoelectric properties.¹ Some applications of biosensors include determination of physiological parameters, quality, and food safety, detection of contaminants in liquids, bacterial growth and discovery of metabolites in human body fluids.²

The detection of contaminants at low concentrations such as pesticides and other chemical elements in aqueous media using conventional techniques is low sensitive, requiring displacement of the sample to specialized laboratories and a long time for its analysis.³The conventional electrochemical techniques, as the cyclic voltammetry, causes damaged in organic compounds for measurements of inorganic material in aqueous solutions.⁴ Chemicals compounds present in water with minimal quantities have a significant effect on public health, mainly caused by the accumulation and prolonged exposure to these products. Sometimes, conventional detection equipment of chemical contaminants in water has imprecision measurements in lower concentrations.⁵ The biosensors are considered as a powerful analytic tool. These devices have a faster time response, high sensitivity and selectivity for measurements in biological and chemical risk environments.⁶ The biosensors allow integration with electronic equipment to perform analyses in real time.⁷The manufacture of biosensors to measure pollutants in aqueous media has some advantages as:⁸

Easy synthesis in powder form. Allowing easy mounting on sensor elements.
Conformation of multiple substrates to obtain matrices of multiple contaminant sensors.
Versatility in the functionalization process to detect a specific type of pollutant.
Implementation of high sensitivity and low-cost sensor systems for the detection of macromolecules by electrical impedance spectroscopy.

The biosensors are classified according to the heterogeneity of materials, their structural components according of chemical interaction, recognition element based on physical or physiological mechanisms, and the signal detection mechanisms using a transduction system. The biosensors can be based on screen printed electrodes (SPE) with a deposited layer of a polymer and nanoparticles. These substrates can have behavior as an Ion-sensitive field-effect transistors (ISFET). An electric response of biosensor changes with contaminants particles, here, the impedance measurements are affected with molecules over electrode substrate.⁹ An appropriate technique for each biosensor depends on the objective molecule, in some cases, the development process can be longer in time due to the non-stability process of the nanoparticle.¹⁰ Carbon-based compounds as graphite paste, graphene and nanotubes are used for the construction of biosensors and in pharmaceuticals samples with good results.¹¹Graphene biosensor has been used to detect glucose, cancer, antibodies, heavy metals, pathogenic bacteria combined with electric measurements.¹² The biosensor devices have higher development on three lines of research: food, agriculture and human biological materials. The analysis of contaminants in water based on a biosensor requires detecting pesticides, antibiotics, and various microorganisms that affect health in human.¹³

Combinations of other measuring techniques together with biosensors have been used and reported in literature over the last decade. One of those technique is Electrical Impedance Spectroscopy (EIS), which is a non-destructive technique to analyze samples of any material solid and liquid including chemical composes and biological tissues. The EIS measurements in a frequency range use several electrodes geometries and covering and generating a characteristic spectrum from the material under test. The limitations of the technique correspond to processes of linearity, stability, and causality, depending on the precision of the instrumentation and experimental procedures.¹⁰ EIS was used to detect contaminants in water as Sodium Nitrate (NaNO₃), Ammonium Nitrate (NH₄NO₃)¹⁴and f di(2-ethyl-hexyl) phthalate (DEHP),¹⁵ bacterial (Listeria monocytogenes)¹⁶ with a higher correlation.

EIS is a potential alternative compared to cyclic voltammetry methodologies, a non-destructive approach to the use of dilute products during the analysis procedures, guaranteeing high repetitiveness.¹⁷ Also, this technique can be used in situ applications due to low cost, portability and wireless circuits.¹⁸ Limitation of biosensors depending on molecule used as a transducer. The regulation and activation mechanisms have restrictions, and they can generate similar responses. For this purpose, the biosensors require several laboratory tests to reduce uncertainly.¹⁹

Conclusion

A combined technique using a biosensor with EIS can reduce the technical limitations to characterize water quality in situ. The main advantages with this fusion is time reduction to obtain a data, a higher selectivity, specificity, portability, easy handling and low cost. The results allow to take decisions about safe and innocuous potable water treatment and irrigation to culture.