Development Of Electrochemical Biosensors Research Articles

Feasibility investigation and development of microbial electrochemical biosensors for marine pollution monitoring

Electrochemical biosensor, as a real-time and rapid detection method, has rarely been explored in marine monitoring. In present work, microbial electrochemical biosensors based on two design strategies: disperse system and integrated microbial electrode, were systematically discussed and their feasibility in marine biotoxicity assessment were investigated. An isolation method was initially investigated to eliminate the potential interference and detect the biological response accurately. The influence of water salinity on the current response was eliminated by adopting the salt-tolerant bacteria Staphylococcus aureus as test microorganism and buffer solution with sufficient ionic strength. The biotoxicity of heavy metal ions and pesticides were sensitively determined. Furthermore, a novel integrated microbial biosensor was designed by immobilizing S. aureus with a redox-active gel that consists of chitosan and poly (diallyl dimethyl ammonium chloride) mixture and confined potassium ferricyanide via electrostatic interaction. The IC50 values for Cu2+, Zn2+, Cr2O72− and Ni2+ were 3.01 mg/L, 1.34 mg/L, 7.64 mg/L and 9.41 mg/L, respectively. This work not only verified the feasibility of electrochemical biosensor in marine pollution monitoring, but also compared the pros and cons of two biosensor design strategies, which provide a guidance for the future development and application of marine monitoring devices based on electrochemical method.

SELF-ASSEMBLED MULTILAYERS OF WATER GLUCOSE MODIFIED-CHITOSAN AND GLUCOSE OXIDASE FOR DETECTION OF GLUCOSE IN MILK SAMPLES

Background: A crucial aspect of electrochemical enzymatic biosensor development is the immobilization of the enzymes, as it directly influences the sensitivity of the bioelectrode. Among the different methods used to incorporate enzymes on the surface of the transducers, layer-by-layer (LbL) self-assembly based on electrostatic interaction with polyelectrolytes of opposite charge stands out due to its simplicity and reproducibility. Aims: The aim of the work was to develop an electrochemical glucose biosensor by LbL assembly of a new functionalized chitosan polycation and the enzyme glucose oxidase (GOx). Methods: Chitosan was chemically functionalized with glucose by the Maillard reaction. The resulting polycation, named G-Chit, is soluble in the medium compatible with the enzyme. The bioelectrode was obtained by alternating adsorption of G-Chit and GOx onto carbon paste electrodes. By selecting the number of bilayer of G-Chit/GOX, the enzyme concentration, and the pH, the electroanalytical performance of the biosensor was optimized. The electrochemical responses were characterized by cyclic voltammetry and chronoamperometry. Results: Under optimized experimental conditions, the biosensor exhibited a sensitivity of (0.81 ± 0.03) µA mM-1 in a glucose concentration range of (0.18 to 1.75) mM. Discussion: Results indicated that catalytic response increases both with the number of G-Chit/GOx bilayers and the enzyme concentration, obtaining the best responses for 3 bilayers and 2 mg mL-1, respectively, while the optimum working pH value was 7.0. Conclusions: The analytical response of the biosensor was tested in milk samples with negligible matrix effects, suggesting a potential application in other dairy products. Results show that G-Chit appears promising for the immobilization of enzymes.

Recent Advances in Electrochemical Biosensors for Monitoring Animal Cell Function and Viability

Redox reactions in live cells are generated by involving various redox biomolecules for maintaining cell viability and functions. These qualities have been exploited in the development of clinical monitoring, diagnostic approaches, and numerous types of biosensors. Particularly, electrochemical biosensor-based live-cell detection technologies, such as electric cell-substrate impedance (ECIS), field-effect transistors (FETs), and potentiometric-based biosensors, are used for the electrochemical-based sensing of extracellular changes, genetic alterations, and redox reactions. In addition to the electrochemical biosensors for live-cell detection, cancer and stem cells may be immobilized on an electrode surface and evaluated electrochemically. Various nanomaterials and cell-friendly ligands are used to enhance the sensitivity of electrochemical biosensors. Here, we discuss recent advances in the use of electrochemical sensors for determining cell viability and function, which are essential for the practical application of these sensors as tools for pharmaceutical analysis and toxicity testing. We believe that this review will motivate researchers to enhance their efforts devoted to accelerating the development of electrochemical biosensors for future applications in the pharmaceutical industry and stem cell therapeutics.

Ratiometrically homogeneous electrochemical biosensor based on the signal amplified strategy of dual DNA nanomachines for microRNA analysis

Precise and sensitive microRNA (miRNA) analysis is very significant for early disease diagnosis. In this work, a dual DNA nanomachines-based homogeneous electrochemical biosensor was constructed for the sensitively ratiometric detection of miRNA by a nicking enzyme (Nt.AlwI)-assisted cycling signal amplification strategy. The Co-based metal organic frameworks (Co-MOFs) and toluidine blue (TB) were employed as signal probes and internal reference probes, respectively. The introduction of internal reference probes can actually calibrate the interferent factors of the analytical system to improve the stability in detection procedure. In addition, with the help of the magnetic separation technique, the homogeneous electrochemical biosensor provides a more simpler way for the development of immobilization-free electrochemical miRNA biosensors, avoiding the complex modification procedure of traditional electrochemical biosensing interfaces. Consequently, taking advantages of this proposed dual DNA nanomachines-based homogeneous electrochemical biosensor, the highly sensitive and selective detection of miRNA-141 as model could be accomplished in ranging from 1 fM to 10 nM with detection limit of 0.46 fM. This strategy exhited good sensitivity and stability to integrate the nicking enzyme-powered dual DNA nanomachines with the ratiometric electrochemical output modes, which open new opportunities for the sensitive and reliable diagnosis of miRNA-related diseases.

Recent advances in development of electrochemical biosensors for the detection of biogenic amines.

Biogenic amines (BAs) are widely found in food as a consequence of diverse factors including free amino acid availability, microbial production of decarboxylases, and variations in processing and storage conditions. Hence, BAs are considered as an important marker for determining the freshness and quality of food. Owing to the documentation of BAs in different dietary products, their numerous negative impacts on human health have reported to be a serious concern in past few decades. Therefore, the quantification of these chemical species in food becomes crucial as it can immensely contributes toward control of new episodes on food intoxication in humans. In this line, various chromatographic and colorimetric methods have been developed to detect BAs. However, these methods are in use from a longer time, still are limited by high cost, lengthy procedures, huge infrastructure and skilled personnel requirements that hinder their on-field application. In pursuit of a reliable method offering accurate detection of BAs, this review presents the state-of-the-art of electrochemical strategies for BAs sensing in food. The core of the review discusses about the widely employed electrochemical transducers, such as amperometric, potentiometric, impedimetric and conductometric-based BAs biosensors with significant findings of research work conducted previously. The application of electrochemical sensors to analyze BAs in different fields including food systems (fermented and non-fermented types) and smart packaging systems has been reviewed. Moreover, existing challenges and further available prospects for the development of rapid, facile, and sensitive electrochemical strategies for on-site determination of BAs have also been discussed.

Label-Free Immunosensor Based on Liquid Crystal and Gold Nanoparticles for Cardiac Troponin I Detection.

According to the World Health Organization (WHO), cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity worldwide. The development of electrochemical biosensors for CVD markers detection, such as cardiac troponin I (cTnI), becomes an important diagnostic strategy. Thus, a glassy carbon electrode (GCE) was modified with columnar liquid crystal (LCcol) and gold nanoparticles stabilized in polyallylamine hydrochloride (AuNPs-PAH), and the surface was employed to evaluate the interaction of the cTnI antibody (anti-cTnI) and cTnI for detection in blood plasma. Morphological and electrochemical investigations were used in the characterization and optimization of the materials used in the construction of the immunosensor. The specific interaction of cTnI with the surface of the immunosensor containing anti-cTnI was monitored indirectly using a redox probe. The formation of the immunocomplex caused the suppression of the analytical signal, which was observed due to the insulating characteristics of the protein. The cTnI-immunosensor interaction showed linear responses from 0.01 to 0.3 ng mL-1 and a low limit of detection (LOD) of 0.005 ng mL-1 for linear sweep voltammetry (LSV) and 0.01 ng mL-1 for electrochemical impedance spectroscopy (EIS), showing good diagnostic capacity for point-of-care applications.

Paper-Based Electrochemical Biosensors for Food Safety Analysis

Nowadays, foodborne pathogens and other food contaminants are among the major contributors to human illnesses and even deaths worldwide. There is a growing need for improvements in food safety globally. However, it is a challenge to detect and identify these harmful analytes in a rapid, sensitive, portable, and user-friendly manner. Recently, researchers have paid attention to the development of paper-based electrochemical biosensors due to their features and promising potential for food safety analysis. The use of paper in electrochemical biosensors offers several advantages such as device miniaturization, low sample consumption, inexpensive mass production, capillary force-driven fluid flow, and capability to store reagents within the pores of the paper substrate. Various paper-based electrochemical biosensors have been developed to enable the detection of foodborne pathogens and other contaminants that pose health hazards to humans. In this review, we discussed several aspects of the biosensors including different device designs (e.g., 2D and 3D devices), fabrication techniques, and electrode modification approaches that are often optimized to generate measurable signals for sensitive detection of analytes. The utilization of different nanomaterials for the modification of electrode surface to improve the detection of analytes via enzyme-, antigen/antibody-, DNA-, aptamer-, and cell-based bioassays is also described. Next, we discussed the current applications of the sensors to detect food contaminants such as foodborne pathogens, pesticides, veterinary drug residues, allergens, and heavy metals. Most of the electrochemical paper analytical devices (e-PADs) reviewed are small and portable, and therefore are suitable for field applications. Lastly, e-PADs are an excellent platform for food safety analysis owing to their user-friendliness, low cost, sensitivity, and a high potential for customization to meet certain analytical needs.

2D MXene-Based Biosensing: A Review.

MXene emerged as decent 2D material and has been exploited for numerous applications in the last decade. The remunerations of the ideal metallic conductivity, optical absorbance, mechanical stability, higher heterogeneous electron transfer rate, and good redox capability have made MXene a potential candidate for biosensing applications. The hydrophilic nature, biocompatibility, antifouling, and anti-toxicity properties have opened avenues for MXene to perform in vitro and in vivo analysis. In this review, the concept, operating principle, detailed mechanism, and characteristic properties are comprehensively assessed and compiled along with breakthroughs in MXene fabrication and conjugation strategies for the development of unique electrochemical and optical biosensors. Further, the current challenges are summarized and suggested future aspects. This review article is believed to shed some light on the development of MXene for biosensing and will open new opportunities for the future advanced translational application of MXene bioassays.

Current Challenges and Developments in Perovskite-Based Electrochemical Biosensors for Effective Theragnostics of Neurological Disorders.

Early-stage diagnosis of neurological disease and effective therapeutics play a significant role in improving the chances of saving lives through suitable and personalized courses of treatment. Biomolecules are potential indicators of any kind of disorder in a biological system, and they are recognized as a critical quantitative parameter in disease diagnosis and therapeutics, collectively known as theragnostics. The effective diagnosis of neurological disorders solely depends on the detection of the imbalance in the concentration of neurological biomarkers such as nucleic acids, proteins, and small metabolites in bodily fluids such as blood serum, plasma, urine, etc. This process of neurological biomarker detection can lead to an effective prognosis with a prediction of the treatment efficiency and recurrence. While review papers on electrochemical, spectral, and electronic biosensors for the detection of a wide variety of biomarkers related to neurological disorders are available in the literature, the prevailing challenges and developments in perovskite-based biosensors for effective theragnostics of neurological disorders have received scant attention. In this Mini-Review, we discuss the topical advancements in design strategies of perovskite-based electrochemical biosensors with detailed insight into the detection of neurological disease or disorder-specific biomarkers and their trace-level detection in biological fluids with high specificity and sensitivity. The tables in this Review give the performance analysis of recently developed perovskite-based electrochemical biosensors for effective theragnostics of neurological disorders. To conclude, the current challenges in biosensing technology for early diagnosis and therapeutics of neurological disorders are discussed along with a forecast of their anticipated developments.

Rapid Quantitative Detection of Live Escherichia coli Based on Chronoamperometry.

The rapid quantitative detection of Escherichia coli (E. coli) is of great significance for evaluating water and food safety. At present, the conventional bacteria detection methods cannot meet the requirements of rapid detection in water environments. Herein, we report a method based on chronoamperometry to rapidly and quantitatively detect live E. coli. In this study, the current indicator i0 and the electricity indicator A were used to record the cumulative effect of bacteria on an unmodified glassy carbon electrode (GCE) surface during chronoamperometric detection. Through the analysis of influencing factors and morphological characterization, it was proved that the changes of the two set electrochemical indicator signals had a good correlation with the concentration of E. coli; detection time was less than 5 min, the detection range of E. coli was 104–108 CFU/mL, and the error range was <30%. The results of parallel experiments and spiking experiments showed that this method had good repeatability, stability, and sensitivity. Humic acid and dead cells did not affect the detection results. This study not only developed a rapid quantitative detection method for E. coli in the laboratory, but also realized a bacterial detection scheme based on the theory of bacterial dissolution and adsorption for the first time, providing a new direction and theoretical basis for the development of electrochemical biosensors in the future.

Starch-Based Electrochemical Sensors and Biosensors: A Review

Natural green compounds for sensor modification (binders) are challenging in electrochemistry. Starch is a carbohydrate biopolymer that has been used extensively in the development of biomaterials for the food industry due to its ability to impart textural characteristics and provide gelling or film formation. In particular, the excellent film-forming characteristics have been used for the development of new surface modifying architectures for electrodes. Here, we highlight a very comprehensive overview of the properties of interest of various types of starch in conjunction with (bio)materials in the chemical modification of sensors and biosensors. Throughout the review, we first give an introduction to the extraction, applications, and properties of starches followed by an overview of the prospects and their possible applications in electrochemical sensors and biosensors. In this context, we discuss some important characteristics of starches and different strategies of their film formation with an emphasis on their role in the development of electrochemical sensors and biosensors highlighting their main contributions to enhancing the performance of these devices and their applications in environmental and clinical samples.Graphical

Recent development and application of ratiometric electrochemical biosensor

• Different categories of ratiometric electrochemical biosensors are described. • The applications of ratiometric electrochemical biosensors are discussed. • The main challenges and prospects in this field are proposed. As one kind of sensitive analysis devices, electrochemical biosensors (ECBSs) convert biological activities into quantifiable electrical signals depending on biological recognitions. Due to their simple operation, low background signal, high sensitivity and stable performance, ECBSs have attracted widespread attentions. However, majority of ECBSs adopt a single-signal output method, which may inevitably be affected by environment conditions and operating procedures, thus leading to inaccurate results. In order to overcome these issues, ratiometric electrochemical biosensors (RECBSs) have been explored. In RECBSs, internal reference substances are introduced to provide a built-in correction, which endow the biosensors with superior sensitivity and accuracy. This article reviews different types of RECBSs, as well as their latest applications in the detection of proteins, nucleic acids, small biomolecules and ions. In addition, major challenges in this field are outlined. Some suggestions for their developments in the future are also highlighted.

In-situ growth of nitrogen-doped carbonized polymer dots on black phosphorus for electrochemical DNA biosensor of Escherichia coli O157: H7

Sensitive and accurate detection technology for pathogenic bacteria is of great social and economic significance in foodborne disease and food safety. In this paper, a novel portable electrochemical DNA biosensor for the detection of specific DNA sequence of Escherichia coli (E. coli) O157: H7 was constructed. To enhance the performance of the electrochemical sensor, a functionalized nitrogen-doped carbonized polymer dots in-situ grown on few-layer black phosphorus (N-CPDs@FLBP) was synthesized and used as the modifier on the surface of screen-printed electrode. Combining gold nanoparticles as immobilization matrix and methylene blue as electrochemical indicator, the analytical performance of this electrochemical DNA biosensor was evaluated using standard complementary ssDNA sequence in the linear concentration range from 1.0 × 10−19 to 1.0 × 10−6 mol/L with a low detection limit as 3.33 × 10−20 mol/L (3 σ). Furthermore, the portable electrochemical DNA biosensor was proposed based on polymerase chain reaction amplification for the detection of the E. coli O157: H7 genomic DNA from chicken meat, which verified the feasibility for practical samples detection. The research has great theoretical and practical significance for the development of electrochemical biosensor of pathogenic bacteria.

Electrochemical (Bio)Sensors Based on Covalent Organic Frameworks (COFs).

Covalent organic frameworks (COFs) are defined as crystalline organic polymers with programmable topological architectures using properly predesigned building blocks precursors. Since the development of the first COF in 2005, many works are emerging using this kind of material for different applications, such as the development of electrochemical sensors and biosensors. COF shows superb characteristics, such as tuneable pore size and structure, permanent porosity, high surface area, thermal stability, and low density. Apart from these special properties, COF’s electrochemical behaviour can be modulated using electroactive building blocks. Furthermore, the great variety of functional groups that can be inserted in their structures makes them interesting materials to be conjugated with biological recognition elements, such as antibodies, enzymes, DNA probe, aptamer, etc. Moreover, the possibility of linking them with other special nanomaterials opens a wide range of possibilities to develop new electrochemical sensors and biosensors.

Electrochemical Determination of Interaction between SARS-CoV-2 Spike Protein and Specific Antibodies.

The serologic diagnosis of coronavirus disease 2019 (COVID-19) and the evaluation of vaccination effectiveness are identified by the presence of antibodies specific to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this paper, we present the electrochemical-based biosensing technique for the detection of antibodies specific to the SARS-CoV-2 proteins. Recombinant SARS-CoV-2 spike proteins (rSpike) were immobilised on the surface of a gold electrode modified by a self-assembled monolayer (SAM). This modified electrode was used as a sensitive element for the detection of polyclonal mouse antibodies against the rSpike (anti-rSpike). Electrochemical impedance spectroscopy (EIS) was used to observe the formation of immunocomplexes while cyclic voltammetry (CV) was used for additional analysis of the surface modifications. It was revealed that the impedimetric method and the elaborate experimental conditions are appropriate for the further development of electrochemical biosensors for the serological diagnosis of COVID-19 and/or the confirmation of successful vaccination against SARS-CoV-2.

Development of electrochemical biosensor: Voltammetric analysis of lymphocytes and indication activation of complement system

This work reports the development of an electrochemical biosensor after immobilization of the lymphocytes to detect the reaction between antibodies and specific HLA antigens present in the serum samples. A clean homemade gold electrode with voltammetric polycrystalline characteristics was used. Lymphocytes were immobilized and tested with positive and negative human serum and complements on the gold electrode. The experiments were carried out in a cell with three electrodes: working - gold, reference - Ag/AgCl/sat. KCl and auxiliary - platinum. The cyclic voltammetric analyses of immobilized lymphocytes on the gold surface presented anodic current equal to 1.78 μA at c.a. 0.50 V vs. Ag/AgCl/sat. KCl. The electrochemical responses of the serum (positive and negative) and complement do not show signs of oxidation or reduction in the potential range used. The electrodes with cells and positive serum showed the amplified current signal in the oxidation potential of the cells. The electrode was developed to verify the antigen antibody reaction, present lymphocyte cell and human serum samples. The electrode was qualitatively efficient when compared to the methods of flow cytometric analysis and complement dependent cytotoxicity, being able to be used with operational and economic advantages.

Fabrication of Au/Fe3O4/RGO based aptasensor for measurement of miRNA-128, a biomarker for acute lymphoblastic leukemia (ALL).

Due to their high sensitivity, simplicity, portability, self‐contained, and low cost, the development of electrochemical biosensors is a beneficial way to diagnose and anticipate many types of cancers. An electrochemical nanocomposite‐based aptasensor is fabricated for the determination of miRNA‐128 concentration as the acute lymphoblastic leukemia (ALL) biomarker for the first time. The aptamer chains were immobilized on the surface of the glassy carbon electrode (GCE) through gold nanoparticles/magnetite/reduced graphene oxide (AuNPs/Fe3O4/RGO). Fast Fourier transform infrared (FTIR), X‐ray diffraction (XRD), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM) were used to characterize synthesized nanomaterials. Cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) were used to characterize the modified GCE in both label‐free and labeled methods. The results indicate that the modified working electrode has high selectivity and for miRNA‐128 over other biomolecules. The hexacyanoferrate redox system typically operated at around 0.3 V (vs. Ag/AgCl), and the methylene blue redox system ran at about 0 V, were used as an electrochemical probe. The detection limit and linear detection range for hexacyanoferrate and methylene blue are 0.05346 fM, 0.1–0.9 fM, and 0.005483 fM, 0.01–0.09 fM, respectively. The stability and diffusion control analyses were performed as well. In both label‐free and labeled methods, the modified electron showed high selectivity for miRNA‐128. The use of methylene blue as a safer redox mediator caused miRNA‐128 to be detected with greater accuracy at low potentials in PBS media. The findings also show the substantial improvement in detection limit and linearity by using reduced graphene oxide‐magnetite‐gold nanoparticles that can be verified by comparing with previous studies on the detection of other miRNAs.

The Performance of Polyaniline Electropolymerization at Various Acidic Electrolytes on Gold Electrodes for Electrochemical Biosensor Application

Polyaniline (PANI), a conductive polymer, has been played a significant role as an electrode material for electrochemical biosensor development. In this study, the electrochemical properties of PANI synthesized in two different acid dopants, i.e. 1.0 M HCl and 0.50 M H2SO4using chronopotentiometry, were investigated. The surface morphologies of the PANI modified gold electrodes were observed using SEM and EDS. The PANI electrodeposition times were also considered. The electrochemical characteristics in terms of the peak-to-peak potential separations (ΔEp), the current of the oxidation (Ipa), and reversible redox properties were investigated using cyclic voltammetry. The results showed that the modified electrode with PANI electropolymerization in H2SO4 as a dopant performed significantly better electrochemically than PANI in HCl at all electrodeposition times. In particular, the PANI prepared in H2SO4 with the electrodeposition time of 120 s demonstrated the best performance in terms of electron transfer and reversible redox reaction.

Electricity, chemistry and biomarkers: an elegant and simple package: The potential of electrochemical biosensors for developing novel point-of-care diagnostics: The potential of electrochemical biosensors for developing novel point-of-care diagnostics.

Electrochemical sensors to measure biomarkers from complex samples are a tried and tested technology with large untapped potential for addressing important public health needs.

Technological advancements in bio-recognition using liquid crystals: Techniques, applications, and performance.

The application of liquid crystal (LC) materials has undergone a modern-day renaissance from its classical use in electronics industry as display devices to new-fangled techniques for optically detecting biological and chemical analytes. This review article deals with the emergence of LC materials as invaluable material for their use as label-free sensing elements in the development of optical, electro-optical and electrochemical biosensors. The property of LC molecules to change their orientation on perturbation by any external stimuli or on interaction with bioanalytes or chemical species has been utilized by many researches for the fabrication of high sensitive LC-biosensors. In this review article we categorized LC-biosensor based on biomolecular reaction mechanism viz. enzymatic, nucleotides and immunoreaction in conjunction with operating principle at different LC interface namely LC-solid, LC-aqueous and LC-droplets. Based on bimolecular reaction mechanism, the application of LC has been delineated with recent progress made in designing of LC-interface for the detection of bio and chemical analytes of proteins, virus, bacteria, clinically relevant compounds, heavy metal ions and environmental pollutants. The review briefly describes the experimental set-ups, sensitivity, specificity, limit of detection and linear range of various viable and conspicuous LC-based biosensor platforms with associated advantages and disadvantages therein.