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This review provides an overview of recent advances in electrochemical sensors for analyte detection in saliva, highlighting their potential applications in diagnostics and health care. The purpose of this paper is to summarize the current state of the field, identify challenges and limitations and discuss future prospects for the development of saliva-based electrochemical sensors.

The paper reviews relevant literature and research articles to examine the latest developments in electrochemical sensing technologies for saliva analysis. It explores the use of various electrode materials, including carbon nanomaterial, metal nanoparticles and conducting polymers, as well as the integration of microfluidics, lab-on-a-chip (LOC) devices and wearable/implantable technologies. The design and fabrication methodologies used in these sensors are discussed, along with sample preparation techniques and biorecognition elements for enhancing sensor performance.

Electrochemical sensors for salivary analyte detection have demonstrated excellent potential for noninvasive, rapid and cost-effective diagnostics. Recent advancements have resulted in improved sensor selectivity, stability, sensitivity and compatibility with complex saliva samples. Integration with microfluidics and LOC technologies has shown promise in enhancing sensor efficiency and accuracy. In addition, wearable and implantable sensors enable continuous, real-time monitoring of salivary analytes, opening new avenues for personalized health care and disease management.

This review presents an up-to-date overview of electrochemical sensors for analyte detection in saliva, offering insights into their design, fabrication and performance. It highlights the originality and value of integrating electrochemical sensing with microfluidics, wearable/implantable technologies and point-of-care testing platforms. The review also identifies challenges and limitations, such as interference from other saliva components and the need for improved stability and reproducibility. Future prospects include the development of novel microfluidic devices, advanced materials and user-friendly diagnostic devices to unlock the full potential of saliva-based electrochemical sensing in clinical practice.

Coral aggregate seawater concrete (CASC) is a new type of lightweight aggregate concrete that is becoming widely used in reef engineering. To investigate the corrosion behavior of different kinds of rebar in CASC exposed to simulated seawater for 0-270 d, the electrochemical techniques, including linear polarization resistance (LPR) technique and the electrochemical impedance spectroscopy (EIS), were used in the present work.

The electrochemical techniques, including LPR technique and the EIS, were used in the present work.

Based on the time-varying law of linear polarization curves, self-corrosion potential (E_corr), polarization resistance (R_p), corrosion current density (I_corr), corrosion rate (i), and the characteristics of EIS diagrams for different types of rebar in CASC, it can be found that the anti-corrosion property of them can be ranked as epoxy resin coated steel > 2205 duplex stainless steel (2205S) > 316 L stainless steel (316 L) > organic coated steel > ordinary steel. Additionally, the linear regression equation between R_p and charge transfer resistance (R_ct) was established. Finally, the EIS corrosion standard of rebar was established from the LPR corrosion standard, which provides a direct standard for the EIS technique to determine the condition of rebar in CASC.

The linear regression equation between polarization resistance and charge transfer resistance was established. And the EIS corrosion standard of rebar was established from the LPR corrosion standard, which provides a direct standard for the EIS technique to determine the condition of rebar in CASC.

This study attempts to investigate corrosion inhibition properties of 1H-benzimidazole (B) and 1H-benzotriazole (BTA) on aluminum in 0.25 M HCl solution at different concentrations.

To this end, electrochemical techniques including electrochemical noise (EN), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used.

Results showed a greater corrosion inhibition efficiency of BTA than B on aluminum in HCl solution. BTA showed greater tendency to adsorption on the metal surface than B because of the inclusion of three nitrogen atoms.

The novelty of this work is comparing EN data with EIS and potentiodynamic polarization parameters.

The purpose of this paper is to present a novel five‐electrode electrochemical corrosion sensor. Health degradation by the corrosion of steel in civil engineering is a persistent problem. Structural health monitoring (SHM) techniques, including embedded sensors, can greatly improve the quantification of the steel corrosion information, which can lead to promote assessments of structural safety and serviceability. To integrate the corrosion monitoring system in future, the corrosion sensor and the monitoring methods have been explored here in advance. Also, the corrosion monitoring system has been applied preliminarily in the investigation of reinforcing concrete (RC) beams.

First, a novel five‐electrode electrochemical corrosion sensor has been developed as the hardware to provide the platform for corrosion monitoring methods. Second, half‐cell potential of the RC beams has been measured before and after corrosion. Third, galvanostatic step method has been used to excite the steel‐concrete system, and the transient response of the system has been obtained and analyzed. Finally, wavelet transform algorithm has been established to analyze the electrochemical noise (EN) data of the steel bars in RC beams.

The results show that the corrosion sensor can be used effectively as the hardware to support the electrochemical measuring techniques. Much valuable information which is extracted by analyzing the potential response to the galvanostatic pulse excitation can be applied to determine the general corrosion state of the reinforcing steel. For pitting corrosion, the energy distribution plot of EN can be adopted as a benchmark method to identify the presence of the corrosion pit.

The paper provides the key techniques for a SHM system to realize corrosion monitoring of large‐scale RC structures in the future.

The purpose of this paper is to identify corrosion types and corrosion transitions by a novel electrochemical noise analysis method based on Adaboost.

The corrosion behavior of Q235 steel was investigated in typical passivation, uniform corrosion and pitting solution by electrochemical noise. Nine feature parameters were extracted from the electrochemical noise data based on statistical analysis and shot noise theory. The feature parameters were analysis by Adaboost to train model and identify corrosion types. The trained Adaboost model was used to identify corrosion type transitions.

Adaboost algorithm can accurately identify the corrosion type, and the accuracy rate is 99.25%. The identification results of Adaboost for the corrosion type are consistent with corroded morphology analysis. Compared with other machine learning, Adaboost can identify corrosion types more accurately. For corrosion type transition, Adaboost can effectively identify the transition from passivation to uniform corrosion and from passivation to pitting corrosion consistent with corroded morphology analysis.

Adaboost is a suitable method for prediction of corrosion type and transitions. Adaboost can establish the classification model of metal corrosion, which can more conveniently and accurately explore the corrosion types. Adaboost provides important reference for corrosion prediction and protection.

An electrochemical impedance spectroscopy technique based on an equivalent circuit used for the evaluation of metallic substratum/organic coating/electrolyte systems as well as the importance of each parameter and the way to calculate it is analysed. It is emphasised that the classical semi circumference in the complex plot, which describes the response of a parallel RC circuit, is not real axis centred. This fact makes it necessary to consider the organic film and electrochemical double layer capacitance as pseudo‐capacitances which depend on a fractional power of the frequency. Starting from mathematical relationships over the total impedance algorithms based on the least squares methods are proposed to fit experimental data requiring less processing time than iterative techniques. The methodology is described analysing the charge transfer resistance, ionic resistance and dielectric capacitance variation at increasing immersion times for naval steel/chlorinated rubber (with different PVC)/artificial sea water systems. Parameters thus obtained correlate well with the naval steel/organic coating deterioration with time, also determined by using corrosion potential measurements and visual assessment.

The purpose of the paper is to present an update and the latest results from work on a project which could be useful for maskless printed circuit board (PCB) manufacturing.

Copper is plated and etched using a novel electrochemical technique, electrochemical patterning by flow and chemistry, using a masked tool and fully exposed substrate. The micro patterns on the tool are replicated on the substrate via optimum design of the apparatus, choice of electrolyte chemistry and fluid flow.

Linear and square shapes ranging from 5 to 200 μm are transferred using the technique by electrochemical plating and etching. Up to 25 substrates could be processed using a single tool, which indicates that photolithography requirements can be greatly minimised.

The copper lines are transferred to relatively small substrates. The process needs to be scaled up to accommodate larger substrates in order to fully exploit its potential for PCBs.

The paper presents a fundamentally different approach to transfer micron scale pattern using a maskless technology. The platform technology involves using a mask to pattern each substrate; this work shows that micron scale patterns can be transferred without masking by optimising electrochemical reactor technology.

This paper aims to access the protective function of hybrid sol-gel coatings deposited on 304L stainless steel substrate in silane solutions containing a mixture of tetraethoxysilane, methyltriethoxysilane and glycidyloxypropyltrimethoxysilane with different pH values during various immersion periods.

The 304L stainless steels coated through 10 and 30 s of immersion in the silane solutions with pH values of 2.1 and 2.8 were exposed to NaCl solution. The corrosion resistance of the coated substrates was studied through taking advantage of electrochemical noise method as well as atomic force microscopy (AFM), water contact angle and field emission-type scanning electron microscopy (FESEM) surface analysis.

The electrochemical current noise, PSD (I) plot, noise resistance and characteristic charge as parameters extracted from electrochemical noise method indicated the superiority of eco-friendly silane coating deposited on the substrate surface during 10 s exposure to the solution, due to the film uniformity and homogeneity as confirmed by FESEM and AFM. Moreover, immersion of the stainless steel in the silane solution with pH 2.1, characterized by higher hydrolysis ratio, led to more effective corrosion control in the NaCl electrolyte according to the results of electrochemical noise and FTIR measurements.

The noise resistance and characteristic charge as electrochemical noise parameters were only used in this research to evaluate the protective behavior of the water-based silane sol-gel coatings. Future studies should examine the correlation between electrochemical noise data and the parameters extracted from other electrochemical methods, e.g. electrochemical impedance spectroscopy.

The data obtained in this research may provide an effective approach based on electrochemical noise method to screen the silane sol-gel coatings for protection of metallic substrates against corrosion.

According to the literature, no report can be found studying the effect of immersion time on a silane solution, including glycidyloxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane, as well as the silane solution pH on the corrosion resistance of 304L stainless steel in NaCl solution through electrochemical noise method.

To investigate the protective properties of tantalum nitride (TaN) thin films deposited on to various steels immersed in a 3 per cent NaCl solution.

TaN thin films with a thickness of 250 nm were deposited on UNS G10180, UNS S30400 and UNS T11302 steels by means of magnetron sputtering technique. The electrochemical behaviour has been studied in 3 per cent NaCl solution using electrochemical impedance spectroscopy and potentiodynamic polarization. The crystalline structure of the films was investigated by X‐ray diffraction. Surface analysis of the corroded samples was performed using scanning electron microscopy and light optical microscopy. The electrochemical impedance spectra were analysed in the context of equivalent circuit models (ECs).

The ECs incorporate a charge transfer process representing the TaN film on UNS G10180 steel, two time constants for that deposited on UNS T11302 and diffusion behaviour for the TaN film on UNS S30400 steel. TaN films demonstrate their protection properties, which were evidenced by increase of the electrochemical properties compared with the substrate. The major corrosion damage of coatings is caused by defects, pores, droplets and pinholes that allow the electrolyte penetration through the films.

Corrosion protections of steels by TaN thin films.

The information related to corrosion behaviour of TaN films in a chloride solution is poor. This paper presents not only a completely electrochemical characterization, but also the surface analysis of the corroded samples.

Ascorbic acid (AA) is an essential vitamin for human health. Therefore, fast and cost-effective detecting of AA is essential, whether in human or food samples. The purpose of this paper is to develop an electrochemical nanosensor for AA detection.

The proposed nanosensor was developed by printing carbon nanoparticles ink and silver nanoparticles ink on a polydimethylsiloxane (PDMS) substrate. The surface of the PDMS substrate was first treated by corona plasma. Then, the nanomaterials printer was used to deposit both inks on the substrate. The working electrode surface was modified by drop-casting of carbon nanotubes. Morphological evaluation was applied using scanning electron microscopy and cyclic voltammetry. Also, a potentiostat was used to detect AA by differential pulse voltammetry.

It has been shown that the developed nanosensor linearly worked at a range of (0–5 mM), with a limit of detection lower than 0.8 mM and a relative standard deviation of 6.6%.

The developed nanosensor is characterized by a simple and cost-effective sensing tool for AA. In particular, the nanomaterials enhanced the nanosensor’s sensitivity due to the high catalytic activity.