Search Results (166)

Electrochemical biosensors are revolutionizing food testing by addressing critical limitations of conventional strategies that suffer from cost, complexity, and field-deployment challenges. Emerging fluorescence and Raman techniques, while promising, face intrinsic drawbacks like photobleaching and matrix interference in opaque or heterogeneous samples. In contrast, electrochemical biosensors leverage electrical signals to bypass optical constraints, enabling rapid, cost-effective, and pretreatment-free analysis of turbid food matrices. This review highlights their operational mechanisms, emphasizing nano-enhanced signal amplification (e.g., Au nanoparticles and graphene) and biorecognition elements (antibodies, aptamers, and molecularly imprinted polymers) for ultrasensitive assay of contaminants, additives, and adulterants. By integrating portability, scalability, and real-time capabilities, electrochemical biosensors align with global food safety regulations and sustainability goals. Challenges in standardization, multiplexed analysis, and long-term stability are discussed, alongside future directions toward AI-driven analytics, biodegradable sensors, and blockchain-enabled traceability, ultimately fostering precision-driven, next-generation food safety and quality testing. Full article

Glycated hemoglobin (HbA1c) is an important biomarker applied for the diagnosis, evaluation, and management of diabetes; therefore, its accurate determination is crucial. In this study, an innovative nanoplatform was developed, integrating carbon nanotubes (CNTs) with enhanced hydrophilicity achieved through cyclodextrin (CD) functionalization, and combined with gold nanoparticles (AuNPs) electrochemically deposited onto a screen-printed carbon electrode. The nanomaterials significantly improved the analytical performance of the sensor due to their increased surface area and high electrical conductivity. This nanoplatform was employed as a substrate for the covalent attachment of thiolated ferrocene-labeled HbA1c specific aptamer through Au-S binding. The electrochemical signal of ferrocene was covered by a stronger oxidation peak of Fe²⁺ from the HbA1c structure, leading to the elaboration of a nanostructured aptasensor capable of the direct detection of HbA1c. The electrochemical aptasensor presented a very wide linear range (0.688–11.5%), an acceptable limit of detection (0.098%), and good selectivity and stability, being successfully applied on real samples. This miniaturized, simple, easy-to-use, and fast-responding aptasensor, requiring only a small sample volume, can be considered as a promising candidate for the efficient on-site determination of HbA1c. Full article

Aptamers have high specificity and affinity to target analytes, along with good stability and low cost, making them widely used in the detection of target substances, especially in the increasingly popular aptamer-based electrochemical biosensors. Aptamer-based electrochemical biosensors are composed of aptamers as the biorecognition elements and sensors that convert the biological interactions into electrical signals for the quantitative detection of targets. To detect low-abundance target substances, the improvement of the sensitivity of biosensors is a pursuit of researchers. Therefore, different amplification strategies for significantly enhancing the detection sensitivity of biosensors have been explored. Thus, this paper reviews the different amplification strategies with various functional materials to amplify the detection signals. Currently, such strategies commonly use gold nanoparticles to construct electrodes that facilitate the transfer of biological reactions or to obtain enhanced signals through nucleic acid amplification. Some strategies use nucleases for target recycling to further enhance the signals. This review discusses the recent progress in signal amplification methods and their applications, and proposes future directions of study to guide subsequent researchers in overcoming the limitations of previous approaches and to produce reproducible biosensors for clinical applications. Full article

An electrochemical aptasensor was developed for the rapid and sensitive detection of ciprofloxacin (CPX) in milk samples. The device was fabricated on a polyethylene terephthalate (PET) substrate using a screen-printing technique with carbon-based conductive ink. Gold nanoparticles (AuNPs) were incorporated to enhance aptamer immobilization and facilitate electron transfer at the electrode surface. The sensor’s analytical performance was optimized by adjusting key parameters, including AuNP volume, DNA aptamer concentration, and incubation times for both the aptamer and the blocking agent (6-mercapto-1-hexanol, MCH). Differential pulse voltammetry (DPV) measurements demonstrated a linear response ranging from 10 to 50 nmol L⁻¹ and a low detection limit of 3.0 nmol L⁻¹. When applied to real milk samples, the method achieved high recovery rates (101.4–106.7%) with a relative standard deviation below 3.1%, confirming its robustness. This disposable and cost-effective aptasensor represents a promising tool for food safety monitoring, with potential for adaptation to detect other pharmaceutical residues in dairy products. Full article

Sepsis remains a global health emergency, demanding timely and accurate diagnostics to reduce morbidity and mortality. This review critically assesses the recent progress (2020–2025) in the development of electrochemical aptamer-based biosensors for sepsis detection. These biosensors combine aptamers’ high specificity and modifiability with the sensitivity and miniaturization potential of electrochemical platforms. The analysis highlights notable advances in detecting key sepsis biomarkers, such as C-reactive protein (CRP), procalcitonin (PCT), interleukins (e.g., interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α)), lipopolysaccharides (LPSs), and microRNAs using diverse sensor configurations, including a field-effect transistor (FET), impedance spectroscopy, voltammetry, and hybrid nanomaterial-based systems. A comparative evaluation reveals promising analytical performance in terms of the limit of detection (LOD), rapid response time, and point-of-care (POC) potential. However, critical limitations remain, including variability in validation protocols, limited testing in real clinical matrices, and challenges in achieving multiplexed detection. This review underscores translational barriers and recommends future directions focused on clinical validation, integration with portable diagnostics, and interdisciplinary collaboration. By consolidating current developments and gaps, this work provides a foundation for guiding next-generation biosensor innovations aimed at effective sepsis diagnosis and monitoring. Full article

Conventional blood-based detection methods for biomarkers and analytes face significant limitations, including complex processing, variability in blood components, and the inability to provide continuous monitoring. These challenges hinder the early diagnosis and effective management of various health conditions. Electrochemical microneedles (MNs) have emerged as a minimally invasive and highly efficient platform to overcome these barriers, enabling continuous molecular monitoring by directly accessing the interstitial fluid. Electrochemical MNs offer several advantages, including reduced patient discomfort, real-time data acquisition, enhanced specificity, and potential applications in wearable, long-term monitoring. In this review, we first analyze material selection and fabrication techniques to optimize sensor performance, stability, and biocompatibility. We then examine diverse detection strategies utilized in electrochemical MNs, including enzyme-based, aptamer-based, and antibody-based sensing mechanisms, each offering unique benefits in sensitivity and selectivity. Finally, we highlight the integration of electrochemical MN technology with multi-target detection, AI-driven analytics, and theragnostic capabilities. This convergence offers strong potential for smart healthcare and precision medicine. Through these technological innovations, electrochemical MNs are expected to play an important role in advancing continuous, noninvasive health monitoring and personalized medical care. Full article

Aptamers refer to a class of oligonucleotide probes that have demonstrated remarkable capabilities beyond mere genetic coding, including the unique ability to recognize and selectively bind to specific molecular targets. Numerous advantages, including accessibility for targeting a diverse array of molecules and compatibility with different signal amplification and transduction elements, underscore the application of aptamers for delivering rapid and accurate diagnostic tests at the point of care. This review provides a comprehensive summary of the recent advances in aptamer-based point-of-care testing, especially highlighting the innovative applications of aptamers in colorimetric sensors, lateral flow assays, fluorescent biosensors, and electrochemical biosensors. Additionally, current challenges in this burgeoning field and forward-looking perspectives for aptamer-based point-of-care testing are discussed. Full article

Zearalenone (ZEN) is a common mycotoxin widely found in food crops such as corn. The toxicity of ZEN is manifested as multiple hazards to reproduction, genes, cells, and immune systems. Long-term exposure may have a serious impact on health, so it has received extensive attention due to its potential harm to human and animal health. In order to ensure food safety, countries have formulated corresponding ZEN content limit standards and promoted the development of efficient and rapid detection technologies. This paper reviews the research progress of ZEN detection in food based on nanoenzyme electrochemical sensors. Firstly, the basic situation of ZEN was introduced, including its physical and chemical properties, toxicity, and related regulations and standards. Secondly, the advantages and disadvantages of traditional detection methods and new detection technologies are analyzed, and the application progress of electrochemical sensors in ZEN detection is discussed, especially aptamer electrochemical sensors, immune-electrochemical sensors, and nanoenzyme electrochemical sensors. In this paper, the advantages of nanoenzyme electrochemical sensors in ZEN detection are discussed in detail, especially in terms of sensitivity, selectivity, and rapid detection. However, nanoenzyme electrochemical sensors still face some challenges in practical applications, such as high production costs, control of signal amplification effects, and safety issues of nanomaterials. Finally, this paper looks forward to the future development direction of nanoenzyme electrochemical sensors and proposes possible solutions to further improve their stability, reduce costs, and optimize sensing performance. Full article

Pancreatic cancer has a high mortality rate, and both the incidence and mortality are continuing to increase in many countries globally. The poor prognosis of pancreatic cancer is in part due to the challenges in early diagnosis. Improving early-stage pancreatic cancer diagnosis would improve survival outcomes. Aptamer-based biosensors provide an alternative technological approach for the analysis of serum biomarkers with several potential advantages. This review summarizes the major pancreatic cancer serum biomarkers, as well as discusses recent progress in biomarker exploration and aptasensor development. Here, we review both established and novel serum biomarkers identified recently, emphasizing their potential for early-stage pancreatic cancer diagnosis. We also propose strategies for further expanding multiplex biomarker panels beyond the established CA19-9 biomarker to enhance diagnostic performance. We discuss technological advancements in aptamer-based sensors for pancreatic cancer-related biomarkers over the last decade. Optical and electrochemical sensors are highlighted as two primary modalities in aptasensor design, each offering unique advantages. Finally, we propose steps towards clinical application using aptamer-based sensors with multiplexed biomarker detection for improved pancreatic cancer diagnostics. Full article

We developed a sensor consisting of V₂O₅ nanorods and a reduced graphene oxide (rGO) nanocomposite (V₂O₅/rGO) with immobilized DNA aptamers (Apt-NH@V₂O₅/rGO) for the sensitive electrochemical detection of Hg (II). The V₂O₅ nanorods anchored on rGO nanosheets were synthesized using a hydrothermal method. The nanocomposite was analyzed by various powerful physical methods that include X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, the Brunauer–Emmett–Teller (BET) method, and Fourier transform infrared spectroscopy (FTIR). The FE-SEM of V₂O₅ disclosed the nanorod-like structure and uniform anchoring of V₂O₅ on the rGO nanosheet. Moreover, the BET results showed that the V₂O₅/rGO nanocomposite possesses excellent porosity. Furthermore, a glassy carbon electrode (GCE) was modified with Apt-NH@V₂O₅/rGO and used for the electrochemical detection of Hg(II) by differential pulse voltammetry (DPV). The aptasensor exhibited excellent sensitivity and selectivity toward Hg(II) detection, with a limit of detection (LOD) of 5.57 nM, which is below the maximum permissible limit established by WHO for rivers (30 nM). The sensor also exhibited significant stability and good repeatability. Full article

Aptamers have recently become novel probes for biosensors because of their good biocompatibility, strong specificity, and high sensitivity. Biosensors based on peptides or nucleic acid aptamers are used in implantable and wearable devices owing to their ease of synthesis and economic efficiency. Simultaneously, amphoteric ionic peptides are being explored as antifouling layers for biosensors resistant to interference from extraneous proteins in serum. Thus, this paper reviews recently developed aptamer-based biosensors and introduces peptide- and nucleic acid-based biosensors, while focusing on the three primary classes of biosensors: electrochemical sensors, fluorescent or colorimetric biosensors, and electroluminescent sensors. Furthermore, we summarize their general construction strategies, describe specific electrochemical sensors that use peptides as an antipollution layer, and elucidate their advantages. Full article

Understanding brain function requires advanced neural probes to monitor electrical and chemical signaling across multiple timescales and brain regions. Microelectrode arrays (MEAs) are widely used to record neurophysiological activity across various depths and brain regions, providing single-unit resolution for extended periods. Recent advancements in flexible MEAs, built on micrometer-thick polymer substrates, have improved integration with brain tissue by mimicking the brain’s soft nature, reducing mechanical trauma and inflammation. These flexible, subcellular-scale MEAs can record stable neural signals for months, making them ideal for long-term studies. In addition to electrical recording, MEAs have been functionalized for electrochemical neurotransmitter detection. Electroactive neurotransmitters, such as dopamine, serotonin, and adenosine, can be directly measured via electrochemical methods, particularly on carbon-based surfaces. For non-electroactive neurotransmitters like acetylcholine, glutamate, and γ-aminobutyric acid, alternative strategies, such as enzyme immobilization and aptamer-based recognition, are employed to generate electrochemical signals. This review highlights recent developments in flexible MEA fabrication and functionalization to achieve both electrochemical and electrophysiological recordings, minimizing sensor fowling and brain damage when implanted long-term. It covers multi-time scale neurotransmitter detection, development of conducting polymer and nanomaterial composite coatings to enhance sensitivity, incorporation of enzyme and aptamer-based recognition methods, and the integration of carbon electrodes on flexible MEAs. Finally, it summarizes strategies to acquire electrochemical and electrophysiological measurements from the same device. Full article

Rapid and reliable detection of pathogens requires precise and optimized analytical techniques to address challenges in food safety and public health. This study focuses on the parametric characterization of an electrochemical aptasensor for Staphylococcus aureus (S. aureus) iron-regulated surface determinant protein A (IsdA) using cyclic voltammetry (CV) analysis, which offers a robust method for evaluating electrode modifications and electrochemical responses. Key parameters were optimized to ensure maximum sensitivity, including an aptamer concentration of 5 μM, an incubation time of 4 h, a potential range from −0.1 to 0.9 V, and a scan rate of 0.05 V/s. The aptasensor achieved stability and peak performance at pH 7.5 and 25 °C. These conditions were critical for detecting the IsdA protein as a biomarker of S. aureus. The aptasensor applicability was demonstrated by successfully detecting S. aureus in food samples such as milk and apple juice with high specificity and reliability. Zeta potential measurements confirmed the layer-by-layer charge dynamics of the AuNPs-aptamer-IsdA system. This work emphasizes the importance of CV in understanding the performance of the electrochemical sensor, and supports the aptasensor as a practical, sensitive, and portable tool for addressing critical gaps in foodborne pathogen detection. Full article

Monitoring of immune factors, including interferon-gamma (IFN-γ), holds great importance for understanding immune responses and disease diagnosis. Wearable sensors enable continuous and non-invasive detection of immune markers in sweat, drawing significant attention to their potential in real-time health monitoring and personalized medicine. Among these, electrochemical sensors are particularly advantageous, due to their excellent signal responsiveness, cost-effectiveness, miniaturization, and broad applicability, making them ideal for constructing wearable sweat sensors. In this study, we present a flexible and sensitive wearable platform for the detection of IFN-γ, utilizing a DNA hydrogel with favorable loading performance and sample collection capability, and the application of mobile software achieves immediate data analysis and processing. This platform integrates three-dimensional DNA hydrogel functionalized with IFN-γ-specific aptamers for precise target recognition and efficient sweat collection. Signal amplification is achieved through target-triggered catalytic hairpin assembly (CHA), with DNA hairpins remarkably enhancing sensitivity. Ferrocene-labeled reporting strands immobilized on a screen-printed carbon electrode are displayed via CHA-mediated strand displacement, leading to a measurable reduction in electrical signals. These changes are transmitted to a custom-developed mobile application via a portable electrochemical workstation for real-time data analysis and recording. This wearable sensor platform combines the specificity of DNA aptamers, advanced signal amplification, and the convenience of mobile data processing. It offers a high-sensitivity approach to detecting low-abundance targets in sweat, paving the way for new applications in point-of-care diagnostics and wearable health monitoring. Full article

Rapid, effective, and cost-effective methods for large-scale screening of pesticide residues in the environment and agricultural products are important for assessing potential environmental risks and safeguarding human health. Here, we constructed a novel aggregation-induced emission (AIE) electrochemical aptamer (Apt) sensor based on red-emissive sulfur quantum dots (SQDs), which aimed at the rapid screening and quantitative detection of malathion. SQDs were prepared using a two-step oxidation method with good electrochemiluminescence (ECL) optical properties. These SQDs were modified onto the electrode surface to serve as ECL luminophores. Subsequently, Apt was introduced and modified to form a double-helix structure with the complementary chain (cDNA). The ECL signal was reduced because the biomolecules had poor electrical conductivity and inefficient electron transfer. When the target malathion was added, the double helix structure was unraveled, the malathion Apt fell off the electrode surface, and the ECL signal was restored. The linear range of detection was 1.0 × 10⁻¹³–1.0 × 10⁻⁸ mol·L⁻¹, and the detection limit was 0.219 fM. The successful preparation of the sensor not only develops the ECL optical properties of SQDs but also expands the application of SQDs in ECL sensing. Full article