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17 pages, 15366 KB

Open AccessArticle

Toward Ultrasensitive Electrochemical Detection of Ammonia Nitrogen in Drinking Water: PtCo Alloy Nanosheet on Self-Supported Carbon Cloth

by Ziyi Zhuang, Liang Jia, Cong Zhao, Zhiyun An, Jiameng Chen, Chun Zhao and Hui Suo

Sensors 2026, 26(10), 3103; https://doi.org/10.3390/s26103103 - 14 May 2026

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Abstract

Ammonia nitrogen is a key indicator for evaluating drinking water quality, and its accurate determination is of great significance for environmental monitoring and public health protection. In this work, a self-supported electrochemical sensor based on PtCo alloy nanosheets was fabricated on carbon cloth [...] Read more.

Ammonia nitrogen is a key indicator for evaluating drinking water quality, and its accurate determination is of great significance for environmental monitoring and public health protection. In this work, a self-supported electrochemical sensor based on PtCo alloy nanosheets was fabricated on carbon cloth via a one-step electrodeposition strategy. The nanosheet structure facilitates the exposure of abundant electroactive sites and promotes efficient electron transfer. Electrochemical measurements indicate that the PtCo/CC electrode exhibits higher electrocatalytic activity toward ammonia oxidation than monometallic Pt, which can be attributed to the modulation of the Pt electronic structure induced by Co incorporation. Under linear sweep voltammetry, the optimized electrode exhibits a high sensitivity of 32.94 μA μM⁻¹ cm⁻² in the concentration range of 0.7–10 μM and 11.43 μA μM⁻¹ cm⁻² in the range of 10–100 μM, with a low detection limit of 77.9 nM. In addition, the electrode maintains good selectivity in the presence of common interfering ions, along with satisfactory reproducibility and stability. The feasibility of practical application is further confirmed by real water sample analysis. Overall, this work provides an effective strategy for the design of Pt-based alloy electrodes for ammonia nitrogen detection, with potential applications in drinking water quality monitoring. Full article

(This article belongs to the Special Issue Advances in Nanomaterial-Based Electrochemical and Optical Biosensors)

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18 pages, 4838 KB

Open AccessArticle

Affinity Peptide-Based Circularly Permuted Fluorescent Protein Biosensors Loaded in a Microfluidic System for Systemic Lupus Erythematosus Diagnosis

by Shuai Shao, Zerui Yang, Jiaqi Liu, Zhi Li and Bo Liu

Sensors 2026, 26(10), 3024; https://doi.org/10.3390/s26103024 - 11 May 2026

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Abstract

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, with anti-double-stranded DNA (anti-dsDNA) antibodies as its serological biomarkers. However, conventional anti-dsDNA antibody detection methods, which mainly rely on antibody-binding assays, often suffer from limited sensitivity and specificity, cumbersome procedures, and poor suitability for [...] Read more.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, with anti-double-stranded DNA (anti-dsDNA) antibodies as its serological biomarkers. However, conventional anti-dsDNA antibody detection methods, which mainly rely on antibody-binding assays, often suffer from limited sensitivity and specificity, cumbersome procedures, and poor suitability for accurate clinical analysis. Herein, we developed an integrated detection system combining a circularly permuted fluorescent protein (cpFP)-based biosensor with a microfluidic chip for rapid and reliable anti-dsDNA antibody detection. The biosensor, cpR-dsAb-C1, was engineered from mApple by inserting an affinity peptide identified through phage display, enabling specific recognition of the variable region of anti-dsDNA antibodies. The biosensor exhibited good sensitivity, specificity, and anti-interference capability. Furthermore, integration of cpR-dsAb-C1 with a polydimethylsiloxane (PDMS)-based microfluidic chip yielded a microfluidic detection platform with good linearity for rapid antibody analysis. Clinical validation showed significantly higher anti-dsDNA antibody levels in patients with SLE than in healthy controls, and the results were consistent with those obtained using routine clinical methods, with an accuracy exceeding 95%. Overall, this system provides a promising low-cost, efficient, and accurate strategy for the early diagnosis and dynamic monitoring of SLE. Full article

(This article belongs to the Special Issue Advances in Nanomaterial-Based Electrochemical and Optical Biosensors)

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16 pages, 2055 KB

Open AccessArticle

In Situ-Prepared Nickel Oxide Electrodes for Electrochemical Detection of Nitrite via Catalytic Reduction Mechanism

by Yihao Geng, Huicong Zhou, Siyuan Lu, Guanyue Wang, Xing Zhao, Hui Suo and Chun Zhao

Sensors 2026, 26(10), 2932; https://doi.org/10.3390/s26102932 - 7 May 2026

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Abstract

In electrochemical nitrite detection, the strong oxidizing nature of nitrite often leads to high detection potentials, posing a significant challenge. To address this issue, this study successfully fabricated a nickel oxide/carbon cloth (NiO/CC) electrode using a one-step electrodeposition method followed by calcination. Taking [...] Read more.

In electrochemical nitrite detection, the strong oxidizing nature of nitrite often leads to high detection potentials, posing a significant challenge. To address this issue, this study successfully fabricated a nickel oxide/carbon cloth (NiO/CC) electrode using a one-step electrodeposition method followed by calcination. Taking advantage of the excellent electrocatalytic reduction properties of nickel oxide—particularly the surface oxygen vacancies that serve as active sites for efficient nitrite ion adsorption and promote the hydrogenation of the key intermediate (*NO)—the reaction energy barrier is substantially reduced. As a result, the NiO/CC electrode enables high-sensitivity nitrite detection at a low potential. Electrochemical evaluations reveal that the NiO/CC sensor performs excellently at −0.15 V (vs. Hg/HgO), featuring a linear detection range of 10–500 μM, a low detection limit of 0.091 μM (S/N = 3), and a high sensitivity of 2910 μA·mM⁻¹·cm⁻². These results highlight the promise of a catalytic reduction-based strategy for lowering detection potentials and provide a crucial foundation for the rational design of high-performance electrochemical sensing interfaces. Full article

(This article belongs to the Special Issue Advances in Nanomaterial-Based Electrochemical and Optical Biosensors)

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12 pages, 1619 KB

Open AccessFeature PaperArticle

A Target-Displaced Aptamer–cDNA Duplex Strategy on ERGO for Ultrasensitive Turn-On Electrochemical Detection of Ochratoxin A

by Intan Gita Lestari, Seung Joo Jang and Tae Hyun Kim

Sensors 2026, 26(6), 1937; https://doi.org/10.3390/s26061937 - 19 Mar 2026

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Abstract

Ochratoxin A (OTA) is a highly toxic mycotoxin commonly detected in food and agricultural products, requiring sensitive analytical methods for reliable monitoring. Herein, we report an ultrasensitive turn-on electrochemical aptasensor for OTA detection based on a target-induced displacement of an aptamer–complementary DNA (cDNA) [...] Read more.

Ochratoxin A (OTA) is a highly toxic mycotoxin commonly detected in food and agricultural products, requiring sensitive analytical methods for reliable monitoring. Herein, we report an ultrasensitive turn-on electrochemical aptasensor for OTA detection based on a target-induced displacement of an aptamer–complementary DNA (cDNA) duplex assembled on an electrochemically reduced graphene oxide (ERGO)-modified glassy carbon electrode (GCE). In the absence of OTA, a methylene blue (MB)-labeled aptamer hybridized with cDNA is immobilized on the ERGO surface via π–π stacking interactions, forming a rigid duplex that suppresses electron transfer and yields a low electrochemical signal. Upon OTA binding, the aptamer undergoes a conformational transition into a G-quadruplex structure, leading to dissociation of the cDNA strand. This target-induced folding brings the MB redox tag into close proximity to the ERGO surface, markedly accelerating electron transfer and enhancing the cathodic reduction current of MB, thereby producing a pronounced signal-on response in square-wave voltammetry (SWV). The ERGO-modified electrode provides a conductive and stable interface without chemical linkers. Under optimized conditions, the aptasensor shows a linear response to OTA from 10 fM to 100 pM with an ultralow LOD of 0.67 fM, together with high selectivity, good reproducibility, and satisfactory stability. This work demonstrates a simple and effective turn-on aptasensing strategy for sensitive electrochemical detection of OTA. Full article

(This article belongs to the Special Issue Advances in Nanomaterial-Based Electrochemical and Optical Biosensors)

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16 pages, 2838 KB

Open AccessArticle

Rapid and Ultrasensitive Detection of Dioctyltin in Textiles Using Surface-Enhanced Raman Spectroscopy (SERS): Mechanistic Insights and Practical Applications

by Zheyu Shen, Qiang Chen, Xia Gao, Yan Liu, Jiamin Wang and Pei Liang

Sensors 2026, 26(6), 1891; https://doi.org/10.3390/s26061891 - 17 Mar 2026

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Abstract

Organotin compounds (OTCs) are toxic pollutants threatening ecosystems and human health, among which dioctyltin (DOCT), widely used in skin-contact textiles, can induce immune dysfunction and metabolic disorders. Although DOCT levels in textiles are strictly regulated by international standards, traditional GC-MS suffers from cumbersome [...] Read more.

Organotin compounds (OTCs) are toxic pollutants threatening ecosystems and human health, among which dioctyltin (DOCT), widely used in skin-contact textiles, can induce immune dysfunction and metabolic disorders. Although DOCT levels in textiles are strictly regulated by international standards, traditional GC-MS suffers from cumbersome derivatization, unsatisfactory repeatability, and lengthy analysis, highlighting the urgent demand for a rapid and sensitive detection approach. Herein, we developed a fast SERS-based strategy for DOCT determination using size-optimized Au@Ag core–shell nanoparticles as the substrate, which offers simple pretreatment, high efficiency, good uniformity, and excellent reproducibility. The SERS spectra and functional group vibration modes of DOCT were elucidated by density functional theory (DFT) calculations combined with experimental validation, and the peak at 301 cm⁻¹ was identified as the characteristic peak for quantitative analysis. After extractant optimization, the method achieved a low LOD of 0.1 μg/L in real textile samples, with recoveries ranging from 86% to 108% and good linearity from 0.1 to 1000 μg/L (R² = 0.9804). This approach provides a reliable, high-sensitivity alternative for rapid monitoring of DOCT residues in textiles. Full article

(This article belongs to the Special Issue Advances in Nanomaterial-Based Electrochemical and Optical Biosensors)

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26 pages, 5187 KB

Open AccessArticle

Design of Electrochemical Sensor Based on Pumpkin Peel Biomass-Derived Carbon Black-Modified Electrode for the Detection of Lead Ions

by Amal M. Aladwani, Esraa M. Bakhsh, Ekram Y. Danish, Zainab M. Hritani, Kalsoom Akhtar and Sher Bahadar Khan

Sensors 2026, 26(5), 1524; https://doi.org/10.3390/s26051524 - 28 Feb 2026

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Abstract

This study reports a sustainable and experimentally simple electrochemical platform for monitoring trace Pb²⁺ using pumpkin peel-derived carbon black (CB) as a modifier on a Nafion-coated glassy carbon electrode (CB/Nafion-GCE). Agricultural waste pumpkin peels were converted into CB, offering a low-cost and [...] Read more.

This study reports a sustainable and experimentally simple electrochemical platform for monitoring trace Pb²⁺ using pumpkin peel-derived carbon black (CB) as a modifier on a Nafion-coated glassy carbon electrode (CB/Nafion-GCE). Agricultural waste pumpkin peels were converted into CB, offering a low-cost and environmentally friendly sensing material. CB produced at 650 °C was systematically characterized by SEM, TEM, EDX, XRD, FT-IR, and BET, revealing a mesoporous structure, high surface area, and partial graphitization that enlarged the electroactive area and reduced charge transfer resistance relative to the bare GCE. Under optimized square wave anodic stripping voltammetry (SWASV) conditions, the glassy carbon electrode modified with CB produced at 650 °C (CB650-GCE) exhibited a well-defined linear response towards Pb²⁺ with a limit of detection of approximately 0.19 µM and a limit of quantification of about 0.58 µM, together with good selectivity against common coexisting metal ions. The sensor also achieved satisfactory recoveries in tap and seawater samples, demonstrating its potential as a practical, green analytical tool for routine lead surveillance in environmental waters. Full article

(This article belongs to the Special Issue Advances in Nanomaterial-Based Electrochemical and Optical Biosensors)

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19 pages, 5758 KB

Open AccessArticle

Detection of Pesticide Residues Using Three-Dimensional SERS Substrate Based on CNTs/Ag/AgNWs/SiO₂

by Jianjun Ding, Niansong Liu, Ganglin Wang, Naiyu Guo and Chao Sun

Sensors 2025, 25(7), 2316; https://doi.org/10.3390/s25072316 - 5 Apr 2025

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Abstract

In response to the shortcomings of traditional surface-enhanced Raman spectroscopy (SERS) substrates, such as short shelf life, poor uniformity, and low selectivity, this study innovatively proposed a three-dimensional composite substrate of CNTs/Ag/AgNWs/SiO₂. This substrate demonstrates excellent SERS enhancement effects, with a [...] Read more.

In response to the shortcomings of traditional surface-enhanced Raman spectroscopy (SERS) substrates, such as short shelf life, poor uniformity, and low selectivity, this study innovatively proposed a three-dimensional composite substrate of CNTs/Ag/AgNWs/SiO₂. This substrate demonstrates excellent SERS enhancement effects, with a detection limit of 10⁻¹² mol/L for the probe molecule Rhodamine 6G (R6G) and an enhancement factor (EF) of 8.947 × 10⁸. Further experiments confirmed the substrate’s superior uniformity and stability. The enhancement mechanism was investigated using both experimental methods and the Finite Difference Time Domain (FDTD) approach. When commonly used pesticide thiram was used as the target analyte, the detection limit of the substrate reached 0.1 mg/L, which is significantly lower than the pesticide residue standards of China and the European Union. Additionally, the genetic algorithm (GA)-optimized Back Propagation (BP) neural network was introduced for the quantitative analysis of thiram concentrations. The experimental results indicated that the GA-BP algorithm achieved the training prediction accuracy of 92.5% for thiram, demonstrating good network performance. This method shows good selectivity and has broad application prospects in the detection of toxic chemicals, environmental pollutants, and food additives. Full article

(This article belongs to the Special Issue Advances in Nanomaterial-Based Electrochemical and Optical Biosensors)

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Review

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39 pages, 1836 KB

Open AccessReview

Functional Nanomaterials and Nanocomposites for High-Performance Printed Biosensors

by Minwoo Kim, Jeongho Shin, Seeun Yoon and Yongwoo Jang

Sensors 2026, 26(9), 2646; https://doi.org/10.3390/s26092646 - 24 Apr 2026

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Abstract

Printed biosensors have attracted increasing attention as platforms for rapid, low-cost, and portable diagnostics because they can be fabricated on flexible or rigid substrates using scalable printing techniques. Their performance is strongly influenced by both the printing process and the materials employed, since [...] Read more.

Printed biosensors have attracted increasing attention as platforms for rapid, low-cost, and portable diagnostics because they can be fabricated on flexible or rigid substrates using scalable printing techniques. Their performance is strongly influenced by both the printing process and the materials employed, since factors such as ink rheology, particle dispersion, interfacial behavior, and post-processing conditions directly affect device architecture, sensing performance, and manufacturing reliability. This review summarizes recent advances in printed biosensors from the combined perspectives of printing technologies and functional materials. Commonly employed printing techniques, including inkjet, screen, aerosol jet, and roll-to-roll gravure printing, are discussed with emphasis on their processing characteristics and material requirements. The review also examines key material platforms used in printed biosensors, including carbon-based nanomaterials, metal oxides, metal nanoparticles, conductive polymers, dielectric materials, and hybrid composites, highlighting their roles in electrical conductivity, catalytic activity, biomolecule immobilization, mechanical flexibility, and overall analytical performance. Finally, current challenges and emerging research directions are outlined with respect to ink stability, post-processing strategies, sensor reliability, manufacturability, and practical translation. Overall, this review emphasizes that the development of high-performance printed biosensors depends on the synergistic integration of rational material design with optimized printing strategies. Full article

(This article belongs to the Special Issue Advances in Nanomaterial-Based Electrochemical and Optical Biosensors)

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