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Open AccessEditorial

Editorial for Special Issue: “Preparation of Nanomaterial Modified Electrode and Its Sensing Application”

by Dong Liu and Baiqing Yuan

Nanomaterials 2022, 12(22), 4010; https://doi.org/10.3390/nano12224010 - 15 Nov 2022

Viewed by 1116

Abstract

Electrochemical sensors have attracted enormous attention for their precision, high sensitivity, rapid response, and ease-of-use for analysis [...] Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

Research

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15 pages, 4974 KiB

Open AccessArticle

Disposal Immunosensor for Sensitive Electrochemical Detection of Prostate-Specific Antigen Based on Amino-Rich Nanochannels Array-Modified Patterned Indium Tin Oxide Electrode

by Liang Yan, Shuai Xu and Fengna Xi

Nanomaterials 2022, 12(21), 3810; https://doi.org/10.3390/nano12213810 - 28 Oct 2022

Cited by 29 | Viewed by 2081

Abstract

Sensitive detection of prostate-specific antigens (PSA) in serum is essential for the prevention and early treatment of prostate cancer. Simple and disposable electrochemical immunosensors are highly desirable for screening and mobile detection of PSAs in high-risk populations. Here, an electrochemical immunosensor was constructed [...] Read more.

Sensitive detection of prostate-specific antigens (PSA) in serum is essential for the prevention and early treatment of prostate cancer. Simple and disposable electrochemical immunosensors are highly desirable for screening and mobile detection of PSAs in high-risk populations. Here, an electrochemical immunosensor was constructed based on amino-rich nanochannels array-modified patterned, inexpensive, and disposable indium tin oxide (ITO) electrodes, which can be employed for the sensitive detection of PSA. Using an amino-group-containing precursor, a vertically ordered mesoporous silica nanochannel film (VMSF) containing amino groups (NH₂-VMSF) was rapidly grown on ITO. When NH₂-VMSF contained template surfactant micelle (SM), the outer surface of NH₂-VMSF was directionally modified by aldehyde groups, which enabled further covalent immobilization of the recognitive antibody to prepare the immuno-recognitive interface. Owing to the charge-based selective permeability, NH₂-VMSF can electrostatically adsorb negatively charged redox probes in solution (Fe(CN)₆^3−/4−). The electrochemical detection of PSA is realized based on the mechanism that the antigen–antibody complex can reduce the diffusion of redox probes in solution to the underlying electrode, leading to the decrease in electrochemical signal. The constructed immunosensor can achieve sensitive detection of PSA in the range from 10 pg/mL to 1 μg/mL with a limit of detection (LOD) of 8.1 pg/mL. Sensitive detection of PSA in human serum was also achieved. The proposed disposable immunosensor based on cheap electrode and nanochannel array is expected to provide a new idea for developing a universal immunosensing platform for sensitive detection of tumor markers. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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15 pages, 4993 KiB

Open AccessArticle

Covalent Organic Frameworks-TpPa-1 as an Emerging Platform for Electrochemical Sensing

by Gang Li, Baiqing Yuan, Sidi Chen, Liju Gan and Chunying Xu

Nanomaterials 2022, 12(17), 2953; https://doi.org/10.3390/nano12172953 - 26 Aug 2022

Cited by 10 | Viewed by 3158

Abstract

Covalent organic frameworks (COFs) are a new type of metal-free porous architecture with a well-designed pore structure and high stability. Here an efficient electrochemical sensing platform was demonstrated based on COFs TpPa-1 constructed by 1,3,5-triformylphloroglucinol (Tp) with p-phenylenediamine (Pa-1), which possesses abundant nitrogen [...] Read more.

Covalent organic frameworks (COFs) are a new type of metal-free porous architecture with a well-designed pore structure and high stability. Here an efficient electrochemical sensing platform was demonstrated based on COFs TpPa-1 constructed by 1,3,5-triformylphloroglucinol (Tp) with p-phenylenediamine (Pa-1), which possesses abundant nitrogen and oxo-functionalities. COFs TpPa-1 exhibited good water dispersibility and strong adsorption affinities for Pd²⁺ and thus was used as loading support to modify Pd²⁺. The Pd²⁺-modified COFs TpPa-1 electrode (Pd²⁺/COFs) showed high electrocatalytic activity for both hydrazine oxidation reaction and nitrophenol reduction reaction. In addition, TpPa-1-derived nitrogen-doped carbon presented high activity for the electro-oxidation of reduced glutathione (GSH), and sensitive electrochemical detection of GSH was achieved. The presented COFs TpPa-1 can be utilized as a precursor as well as support for anchoring electro-active molecules and nanoparticles, which will be useful for electrochemical sensing and electrocatalysis. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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18 pages, 18145 KiB

Open AccessArticle

Fabrication of an Organofunctionalized Talc-like Magnesium Phyllosilicate for the Electrochemical Sensing of Lead Ions in Water Samples

by Chancellin Nkepdep Pecheu, Sherman Lesly Zambou Jiokeng, Arnaud Kamdem Tamo, Giscard Doungmo, Ingo Doench, Anayancy Osorio-Madrazo, Ignas Kenfack Tonle and Emmanuel Ngameni

Nanomaterials 2022, 12(17), 2928; https://doi.org/10.3390/nano12172928 - 25 Aug 2022

Cited by 5 | Viewed by 2034

Abstract

A talc-like magnesium phyllosilicate functionalized with amine groups (TalcNH₂), useful as sensor material in voltammetry stripping analysis, was synthesized by a sol–gel-based processing method. The characterizations of the resulting synthetic organoclay by scanning electron microscopy (SEM), X-ray diffraction, N₂ sorption [...] Read more.

A talc-like magnesium phyllosilicate functionalized with amine groups (TalcNH₂), useful as sensor material in voltammetry stripping analysis, was synthesized by a sol–gel-based processing method. The characterizations of the resulting synthetic organoclay by scanning electron microscopy (SEM), X-ray diffraction, N₂ sorption isotherms (BET method), Fourier transform infrared spectroscopy (FTIR), CHN elemental analysis and UV–Vis diffuse reflectance spectroscopy (UV–Vis-DRS) demonstrated the effectiveness of the process used for grafting of amine functionality in the interlamellar clay. The results indicate the presence of organic moieties covalently bonded to the inorganic lattice of talc-like magnesium phyllosilicate silicon sheet, with interlayer distances of 1568.4 pm. In an effort to use a talc-like material as an electrode material without the addition of a dispersing agent and/or molecular glue, the TalcNH₂ material was successfully dispersed in distilled water in contrast to natural talc. Then, it was used to modify a glassy carbon electrode (GCE) by drop coating. The characterization of the resulting modified electrode by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) revealed its charge selectivity ability. In addition, EIS results showed low charge transfer resistance (0.32 Ω) during the electro-oxidation of [Fe(CN)₆]³⁻. Kinetics studies were also performed by EIS, which revealed that the standard heterogeneous electron transfer rate constant was (0.019 ± 0.001) cm.s⁻¹, indicating a fast direct electron transfer rate of [Fe(CN)₆]³⁻ to the electrode. Using anodic adsorptive stripping differential pulse voltammetry (DPV), fast and highly sensitive determination of Pb(II) ions was achieved. The peak current of Pb²⁺ ions on TalcNH₂/GCE was about three-fold more important than that obtained on bare GCE. The calculated detection and quantification limits were respectively 7.45 × 10⁻⁸ M (S/N = 3) and 24.84 × 10⁻⁸ M (S/N 10), for the determination of Pb²⁺ under optimized conditions. The method was successfully used to tap water with satisfactory results. The results highlight the efficient chelation of Pb²⁺ ions by the grafted NH₂ groups and the potential of talc-like amino-functionalized magnesium phyllosilicate for application in electrochemical sensors. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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14 pages, 7143 KiB

Open AccessEditor’s ChoiceArticle

Fabrication and Conductive Mechanism Analysis of Stretchable Electrodes Based on PDMS-Ag Nanosheet Composite with Low Resistance, Stability, and Durability

by Chengwei Li, Kai Huang, Tingkang Yuan, Tianze Cong, Zeng Fan and Lujun Pan

Nanomaterials 2022, 12(15), 2628; https://doi.org/10.3390/nano12152628 - 30 Jul 2022

Cited by 9 | Viewed by 2244

Abstract

A flexible and stretchable electrode based on polydimethylsiloxane (PDMS)-Ag nanosheet composite with low resistance and stable properties has been investigated. Under the synergistic effect of the excellent flexibility and stretchability of PDMS and the excellent electrical conductivity of Ag nanosheets, the electrode possesses [...] Read more.

A flexible and stretchable electrode based on polydimethylsiloxane (PDMS)-Ag nanosheet composite with low resistance and stable properties has been investigated. Under the synergistic effect of the excellent flexibility and stretchability of PDMS and the excellent electrical conductivity of Ag nanosheets, the electrode possesses a resistivity as low as 4.28 Ωm, a low resistance variation in the 0–50% strain range, a stable electrical conductivity over 1000 cycles, and a rapid recovery ability after failure caused by destructive large stretching. Moreover, the conductive mechanism of the flexible electrode during stretching is explained by combining experimental tests, theoretical models of contact point-tunneling effect, and finite element simulation. This research provides a simple and effective solution for the structure design and material selection of flexible electrodes, and an analytical method for the conductive mechanism of stretchable electrodes, which has potential for applications in flexible electronic devices, smart sensing, wearable devices, and other fields. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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20 pages, 3644 KiB

Open AccessArticle

A System of Rapidly Detecting Escherichia Coli in Food Based on a Nanoprobe and Improved ATP Bioluminescence Technology

by Zhen Sun, Jia Guo, Wenbo Wan and Chunxing Wang

Nanomaterials 2022, 12(14), 2417; https://doi.org/10.3390/nano12142417 - 14 Jul 2022

Cited by 7 | Viewed by 2211

Abstract

Bacterial contamination is an important factor causing food security issues. Among the bacteria, Escherichia coli is one of the main pathogens of food-borne microorganisms. However, traditional bacterial detection approaches cannot meet the requirements of real-time and on-site detection. Thus, it is of great [...] Read more.

Bacterial contamination is an important factor causing food security issues. Among the bacteria, Escherichia coli is one of the main pathogens of food-borne microorganisms. However, traditional bacterial detection approaches cannot meet the requirements of real-time and on-site detection. Thus, it is of great significance to develop a rapid and accurate detection of bacteria in food to ensure food safety and safeguard human health. The pathogen heat-treatment module was designed in this paper based on the techniques including nanoprobe, pathogen heat-treatment, graphene transparent electrode (GTE), and adenosine triphosphate (ATP) bioluminescence technology. The system mainly consists of two parts: one is the optical detection unit; the other is the data processing unit. And it can quickly and automatically detect the number of bacterial colonies in food such as milk etc. The system uses not only the probe to capture and enrich E. coli by antigen-antibody interaction but also the heat treatment to increase the amount of ATP released from bacterial cells within five minutes. To enhance the detecting accuracy and sensitivity, the electric field generated by GTE is adopted in the system to enrich ATP. Compared to the other conventional methods, the linear correlation coefficient of the system can be reached 0.975, and the system meets the design requirements. Under the optimal experimental conditions, the detection can be completed within 25 min, and the detectable concentration of bacteria is in the range of 3.1 × 10¹–10⁶ CFU/mL. This system satisfies the demands of a fast and on-site inspection. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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13 pages, 2788 KiB

Open AccessArticle

Comprehensive Study of the Chemistry behind the Stability of Carboxylic SWCNT Dispersions in the Development of a Transparent Electrode

by Jovana Stanojev, Stevan Armaković, Sara Joksović, Branimir Bajac, Jovan Matović and Vladimir V. Srdić

Nanomaterials 2022, 12(11), 1901; https://doi.org/10.3390/nano12111901 - 1 Jun 2022

Cited by 4 | Viewed by 2145

Abstract

Single-walled carbon nanotubes (SWCNTs) are well-known for their excellent electrical conductivity. One promising application for SWCNT-based thin films is as transparent electrodes for uncooled mid-IR detectors (MIR). In this paper, a combination of computational and experimental studies were performed to understand the chemistry [...] Read more.

Single-walled carbon nanotubes (SWCNTs) are well-known for their excellent electrical conductivity. One promising application for SWCNT-based thin films is as transparent electrodes for uncooled mid-IR detectors (MIR). In this paper, a combination of computational and experimental studies were performed to understand the chemistry behind the stability of carboxylic SWCNTs (SWCNTs-COOH) dispersions in different solvents. A computational study based on the density functional tight-binding (DFTB) method was applied to understand the interactions of COOH-functionalized carbon nanotubes with selected solvents. Attention was focused on understanding how the protonation of COOH groups influences the binding energies between SWCNTs and different solvents. Thin film electrodes were prepared by alternately depositing PEI and SWCNT-COOH on soda lime glass substrates. To prepare a stable SWCNT dispersion, different solvents were tested, such as deionized (DI) water, ethanol and acetone. The SWCNT-COOH dispersion stability was tested in different solvents. Samples were prepared to study the relationship between the number of depositions, transparency in the MIR range (2.5–5 µm) and conductivity, looking for the optimal thickness that would satisfy the application. The MIR transparency of the electrode was reduced by 20% for the thickest SWCNT layers, whereas sheet resistance values were reduced to 150–200 kΩ/sq. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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16 pages, 4825 KiB

Open AccessArticle

Defect Density-Dependent pH Response of Graphene Derivatives: Towards the Development of pH-Sensitive Graphene Oxide Devices

by Shayan Angizi, Xianxuan Huang, Lea Hong, Md Ali Akbar, P. Ravi Selvaganapathy and Peter Kruse

Nanomaterials 2022, 12(11), 1801; https://doi.org/10.3390/nano12111801 - 25 May 2022

Cited by 12 | Viewed by 2384

Abstract

In this study, we demonstrate that a highly pH-sensitive substrate could be fabricated by controlling the type and defect density of graphene derivatives. Nanomaterials from single-layer graphene resembling a defect-free structure to few-layer graphene and graphene oxide with high defect density were used [...] Read more.

In this study, we demonstrate that a highly pH-sensitive substrate could be fabricated by controlling the type and defect density of graphene derivatives. Nanomaterials from single-layer graphene resembling a defect-free structure to few-layer graphene and graphene oxide with high defect density were used to demonstrate the pH-sensing mechanisms of graphene. We show the presence of three competing mechanisms of pH sensitivity, including the availability of functional groups, the electrochemical double layer, and the ion trapping that determines the overall pH response. The graphene surface was selectively functionalized with hydroxyl, amine, and carboxyl groups to understand the role and density of the graphene pH-sensitive functional groups. Later, we establish the development of highly pH-sensitive graphene oxide by controlling its defect density. This research opens a new avenue for integrating micro–nano-sized pH sensors based on graphene derivatives into next-generation sensing platforms. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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13 pages, 8441 KiB

Open AccessArticle

Copper Cobalt Sulfide Structures Derived from MOF Precursors with Enhanced Electrochemical Glucose Sensing Properties

by Daojun Zhang, Xiaobei Zhang, Yingping Bu, Jingchao Zhang and Renchun Zhang

Nanomaterials 2022, 12(9), 1394; https://doi.org/10.3390/nano12091394 - 19 Apr 2022

Cited by 17 | Viewed by 2837

Abstract

Nonenzymatic electrochemical detection of glucose is popular because of its low price, simple operation, high sensitivity, and good reproducibility. Co-Cu MOFs precursors were synthesized via the solvothermal way at first, and a series of porous spindle-like Cu-Co sulfide microparticles were obtained by secondary [...] Read more.

Nonenzymatic electrochemical detection of glucose is popular because of its low price, simple operation, high sensitivity, and good reproducibility. Co-Cu MOFs precursors were synthesized via the solvothermal way at first, and a series of porous spindle-like Cu-Co sulfide microparticles were obtained by secondary solvothermal sulfurization, which maintained the morphology of the MOFs precursors. Electrochemical studies exhibit that the as-synthesized Cu-Co sulfides own excellent nonenzymatic glucose detection performances. Compared with CuS, Co (II) ion-doped CuS can improve the conductivity and electrocatalytic activity of the materials. At a potential of 0.55 V, the as-prepared Co-CuS-2 modified electrode exhibits distinguished performance for glucose detection with wide linear ranges of 0.001–3.66 mM and high sensitivity of 1475.97 µA·mM⁻¹·cm⁻², which was much higher than that of CuS- and Co-CuS-1-modified electrodes. The constructed sulfide sensors derived from MOF precursors exhibit a low detection limit and excellent anti-interference ability for glucose detection. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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17 pages, 3425 KiB

Open AccessArticle

A Micro Electrochemical Sensor for Multi-Analyte Detection Based on Oxygenated Graphene Modified Screen-Printed Electrode

by Baiqing Yuan, Liju Gan, Gang Li, Chunying Xu and Gang Liu

Nanomaterials 2022, 12(4), 711; https://doi.org/10.3390/nano12040711 - 21 Feb 2022

Cited by 5 | Viewed by 2439

Abstract

Electrode interfaces with both antibiofouling properties and electrocatalytic activity can promote the practical application of nonenzymatic electrochemical sensors in biological fluids. Compared with graphene, graphene oxide (GO) possesses unique properties such as superior solubility (hydrophilicity) in water, negative charge, and abundant oxygenated groups [...] Read more.

Electrode interfaces with both antibiofouling properties and electrocatalytic activity can promote the practical application of nonenzymatic electrochemical sensors in biological fluids. Compared with graphene, graphene oxide (GO) possesses unique properties such as superior solubility (hydrophilicity) in water, negative charge, and abundant oxygenated groups (oxo functionalities) in the plane and edge sites, which play an essential role in electrocatalysis and functionalization. In this work, a micro electrochemical sensor consisting of GO-modified screen-printed electrode and PDMS micro-cell was designed to achieve multi-analyte detection with excellent selectivity and anti-biofouling properties by electrochemically tuning the oxygen-containing functional species, hydrophilicity/hydrophobicity, and electrical conductivity. In particular, the presented electrodes demonstrated the potential in the analysis of biological samples in which electrodes often suffer from serious biofouling. The interaction of proteins with electrodes as well as uric acid was investigated and discussed. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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Review

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44 pages, 2484 KiB

Open AccessReview

Recent Advances in Electrochemical Sensing of Hydrogen Peroxide (H₂O₂) Released from Cancer Cells

by Touqeer Ahmad, Ayesha Iqbal, Sobia Ahsan Halim, Jalal Uddin, Ajmal Khan, Sami El Deeb and Ahmed Al-Harrasi

Nanomaterials 2022, 12(9), 1475; https://doi.org/10.3390/nano12091475 - 26 Apr 2022

Cited by 45 | Viewed by 5866

Abstract

Cancer is by far the most common cause of death worldwide. There are more than 200 types of cancer known hitherto depending upon the origin and type. Early diagnosis of cancer provides better disease prognosis and the best chance for a cure. This [...] Read more.

Cancer is by far the most common cause of death worldwide. There are more than 200 types of cancer known hitherto depending upon the origin and type. Early diagnosis of cancer provides better disease prognosis and the best chance for a cure. This fact prompts world-leading scientists and clinicians to develop techniques for the early detection of cancer. Thus, less morbidity and lower mortality rates are envisioned. The latest advancements in the diagnosis of cancer utilizing nanotechnology have manifested encouraging results. Cancerous cells are well known for their substantial amounts of hydrogen peroxide (H₂O₂). The common methods for the detection of H₂O₂ include colorimetry, titration, chromatography, spectrophotometry, fluorimetry, and chemiluminescence. These methods commonly lack selectivity, sensitivity, and reproducibility and have prolonged analytical time. New biosensors are reported to circumvent these obstacles. The production of detectable amounts of H₂O₂ by cancerous cells has promoted the use of bio- and electrochemical sensors because of their high sensitivity, selectivity, robustness, and miniaturized point-of-care cancer diagnostics. Thus, this review will emphasize the principles, analytical parameters, advantages, and disadvantages of the latest electrochemical biosensors in the detection of H₂O₂. It will provide a summary of the latest technological advancements of biosensors based on potentiometric, impedimetric, amperometric, and voltammetric H₂O₂ detection. Moreover, it will critically describe the classification of biosensors based on the material, nature, conjugation, and carbon-nanocomposite electrodes for rapid and effective detection of H₂O₂, which can be useful in the early detection of cancerous cells. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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19 pages, 5385 KiB

Open AccessReview

In Situ Assembly of Nanomaterials and Molecules for the Signal Enhancement of Electrochemical Biosensors

by Yong Chang, Ning Xia, Yaliang Huang, Zhifang Sun and Lin Liu

Nanomaterials 2021, 11(12), 3307; https://doi.org/10.3390/nano11123307 - 6 Dec 2021

Cited by 9 | Viewed by 2721

Abstract

The physiochemical properties of nanomaterials have a close relationship with their status in solution. As a result of its better simplicity than that of pre-assembled aggregates, the in situ assembly of nanomaterials has been integrated into the design of electrochemical biosensors for the [...] Read more.

The physiochemical properties of nanomaterials have a close relationship with their status in solution. As a result of its better simplicity than that of pre-assembled aggregates, the in situ assembly of nanomaterials has been integrated into the design of electrochemical biosensors for the signal output and amplification. In this review, we highlight the significant progress in the in situ assembly of nanomaterials as the nanolabels for enhancing the performances of electrochemical biosensors. The works are discussed based on the difference in the interactions for the assembly of nanomaterials, including DNA hybridization, metal ion–ligand coordination, metal–thiol and boronate ester interactions, aptamer–target binding, electrostatic attraction, and streptavidin (SA)–biotin conjugate. We further expand the range of the assembly units from nanomaterials to small organic molecules and biomolecules, which endow the signal-amplified strategies with more potential applications. Full article

(This article belongs to the Special Issue Preparation of Nanomaterial Modified Electrode and Its Sensing Application)

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