Electrochemical Biosensor Research Articles

Electrochemical non-enzymatic glucose biosensors based on Au-thiol-linked molecular architectures

In this work, an electrochemical non-enzymatic glucose sensor consisting of di-methanethiol-grafted poly (3,4-propylenedioxythiophene), gold nanoparticles (Au NPs), and reduced graphene oxide (rGO) was synthesized by a one-step method through Au-S chemisorption. The structure and morphology of the as-prepared poly (ProDOT-(MeSH)2)/Au/rGO composite were characterized by FT-IR, XRD, EDX, TEM, SEM, and XPS, and the electrochemical performance of the composite was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) on glassy carbon electrode (GCE). The results show that because of the hydrogen bond interaction between the thiol group on the polymer units and the functional groups on GO, poly (ProDOT-(MeSH)2)/Au/rGO was successfully prepared. In addition, due to the unique morphological structure of the composite and the ability to absorb glucose molecules through hydrogen bonds, the poly(ProDOT-(MeSH)2)/Au/rGO electrode possesses excellent selectivity and unique sensitivity (46.13 μA mM−1 cm−2) for sensing glucose in the linear range of 0.04–16.0 mM with a detection limit of (S/N = 3) 0.01. This paper demonstrates that the poly(ProDOT-(MeSH)2)/Au/rGO composite holds great promise for application as a new glucose sensor in life science.

Study on the performance of MoS2/Au composites for non-enzymatic electrochemical glucose detection

Abstract Glucose concentration is considered an indicator for the diagnosis of diabetes, highlighting the importance of accurate glucose detection. Non-enzymatic electrochemical sensors have been extensively studied for glucose detection applications, with nanocomposites composed of molybdenum disulfide (MoS2) and gold nanoparticles (Au NPs) demonstrating high catalytic activity. In this study, a nanocomposite material composed of MoS2 and Au NPs (MoS2/Au) was synthesized and employed to construct a non-enzymatic electrochemical glucose biosensor. The detection limit of this sensor was explored, reaching as low as 1 mM. Additionally, compared to MoS2, the MoS2/Au nanocomposite exhibited a higher linear correlation coefficient and sensitivity, with a linear range of 1–25 mM and a sensitivity of 417.556 μA mM−1 cm−2. The sensor demonstrated excellent performance within the range of human blood glucose concentrations, showing potential for real-time monitoring and precise measurement of glucose levels. Furthermore, it exhibited good stability and reproducibility. These findings indicate the potential applications of MoS2/Au in biosensors and immunoassays.

Electrochemical biosensor based on copper sulfide/reduced graphene oxide/glucose oxidase construct for glucose detection

Due to the current increase in the number of people suffering from diabetes worldwide, how to monitor the blood glucose level in the human body has become an urgent problem to be solved nowadays. The electrochemical sensor method can be used for real-time glucose monitoring due to its advantages of real-time monitoring capability and high sensitivity. Reduced graphene oxide (rGO) has great potential for application in the field of sensors due to its advantages of large specific surface area, high stability, and good electrical and thermal conductivity. Meanwhile, the synergistic effect between two-dimensional transition metal sulfides and graphene can improve the electrochemical performance of materials due to their similar mechanical flexibility and strength. This article uses flake graphite, copper sulfate, and glucose oxidase (GOx) as raw materials to prepare CuS/rGO/GOx/GCE electrodes, and explores the performance of electrode electrocatalysis for glucose. The results showed that the prepared sensor was characterized by a low detection limit (1.75 nM) and a wide linear range (0.1-100 mM) for glucose detection, displaying a good overall detection performance, and its sensing mechanism and dynamic process were also investigated. In addition, the sensor has outstanding selectivity, anti-interference, repeatability, reproducibility and practicality.

Gold nanoparticles-amplified laccase-based electrochemical biosensor using graphitized carbon@boron carbide as electron transfer promoter

A novel laccase-based electrochemical biosensor was developed based on graphitized carbon coated boron carbide (GC@B4C) particles and gold nanoparticles (AuNPs) as electron transfer promoter and signal amplifier, respectively. AuNPs were in-situ electrodeposited on nickel foam (NF) electrode, and chitosan was used to immobilize laccase (Lac) and GC@B4C particles on AuNPs/NF electrode. The fabricated Lac/GC@B4C/AuNPs/NF electrode showed excellent electrocatalytic activity and good electron transfer kinetics for catechol (CC) oxidation. In addition, Lac/GC@B4C/AuNPs/NF electrode exhibited wide linear range (0.1–500 µM), high sensitivity (157.3 µA mM−1), low detection limit (25 nM), desirable selectivity, favorable stability and satisfactory reproducibility for CC detection. This work provided new idea for the construction of laccase-based electrochemical biosensors.

An electrochemical biosensor for on-glove application: organophosphorus pesticide detection directly on fruit peels

An electrochemical biosensor for on-glove application: organophosphorus pesticide detection directly on fruit peels

Synergistic signal amplification for HER2 biosensing using tetrahedral DNA nanostructures and 2D transition metal carbon/nitride@Au composites via ARGET ATRP

The rising incidence of breast cancer underscores the critical need for accurate and early detection methods, particularly for key biomarkers like human epidermal growth factor receptor 2 (HER2). Here, a synergistic signal amplification electrochemical biosensor was developed for HER2 detection that utilizes tetrahedral DNA nanostructures (TDN), 2D transition metal carbon/nitride@Au (MXene@Au) composites, and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Specifically, TDN serves as the substrate, with the aptamer anchored by the MXene@Au composite support matrix. This design facilitates the generation of electrochemical currents through the ARGET ATRP signal amplification strategy. The robustness and high affinity of TDN minimize surface effects on the electrode and enhance target binding. Additionally, the high conductivity of the MXene@Au composites improves the detection sensitivity of the biosensor. The use of the ARGET ATRP strategy further enhances detection sensitivity. The biosensor exhibits a wide detection range from 10 pg·mL−1 to 10 µg·mL−1 with a remarkable detection limit of 0.39 pg·mL−1, verified under optimal experimental conditions. The designed biosensor offers a significant advancement in the field of oncological diagnostics, providing a highly sensitive, low-cost, and simple method for early HER2 detection, thereby potentially improving treatment outcomes for breast cancer patients.

Conductive single enzyme nanocomposites prepared by in-situ growth of nanoscale polyaniline for high performance enzymatic bioelectrode.

Enzyme-based electrochemical biosensors hold great promise for applications in health/disease monitoring, drug discovery, and environmental monitoring. However, inherently non-conductive nature of proteinaceous enzymes often hampers effective electron transfer at enzyme-electrode interface, limiting biosensor performance of enzyme bioelectrodes. To address this problem, we present an approach to synthesize polyaniline (PAN)-based conductive single enzyme nanocomposites of glucose oxidase (GOx) (denoted as PAN-GOx). To prevent multimerization of enzymes during nanocomposite synthesis and enable single enzyme wrapping, we activate GOx surface with phenylamine groups based on the programmed diffusion of reactants in the reaction solution. Subsequent in-situ polymerization enables the synthesis of nanoscale conductive PAN layer (∼2.7nm thickness) grafted from individual GOx molecule. PAN-GOx retains 83% and 74% of its specific activity and catalytic efficiency, respectively, compared to free GOx, while demonstrating a ∼500% improved conductivity. Furthermore, PAN-GOx-based glucose biosensors show an approximately 16- and 3-fold higher sensitivity compared to biosensors prepared by using free GOx and a mixture of PAN and GOx, respectively. This study provides a facile method to fabricate conductive single enzyme nanocomposites with enhanced electron transfer, which can potentially be further modified and/or compounded with conductive materials for demonstrating high performance enzymatic bioelectrodes.

Robust and washable silk fiber-based electrochemical biosensor for high-performance sensing of hydrogen peroxide

Wearable electronics, especially fiber-based biosensors, show promise in large-scale production and reusability compared with conventional wafer-based electronics. However, it is challenging to use wearable electronics, with less intensity and non-wash ability, to produce fiber-based biosensors for textiles. Here, a robust and washable Prussian blue (PB)-functionalized silk fiber (PB-SF) flexible electrode is reported. Modified cyanotype is successfully employed to immobilize PB nanoparticles (∼18.32 nm) onto silk fibers for hydrogen peroxide (H2O2) detection. The intrinsic mechanical properties of silk fibers are well maintained with slight increases in stress (∼10%) and strain (∼16%). Furthermore, the PB-SF electrode displays good electrochemical H2O2 sensing performance with sensitivity of 716.54 μA/mM·cm2, a linear range of 0.01∼0.6 mM and a low detection limit of 10 μM (S/N=3). Notably, the hybrid PB-SF electrode adapts to mechanical deformations with a series of angles and the electrical signals are not compromised obviously even after 100 home laundry washing cycles. PB modified silk fibers is simple, easy-operating and cost-effective electrode that is suitable for large-scale production as it can be integrated onto e-textiles through typical textile processing methods.

A disposable paper-based electrochemical biosensor for detection of aflatoxin B1 based on a structure-switching aptamer

Aflatoxin B1 (AFB1) is a highly toxic mycotoxin that readily contaminates major food crops. This study presents a novel ratiometric electrochemical paper-based aptasensor for AFB1 detection that utilizes a structure-switching aptamer. The sensor detects AFB1 by folding the DNA aptamer, reducing the electron transfer efficiency between the methylene blue (MB) molecules attached to the DNA and the electrode surface. An inner reference element modified with ferrocene (Fc) is co-assembled on the electrode surface of the paper-based biosensor to enhance the accuracy of AFB1 detection. In the presence of target AFB1, a folded target–aptamer complex is formed, distancing the MB molecules from the electrode and generating a low current signal in a differential pulse voltammetry mode. The ratio of oxidation currents for MB and Fc serves as the metric for monitoring AFB1 levels. The detection range spans from 20.0 to 1000.0 ng mL−1, with a limit of detection of 7.6 ng mL−1. The paper-based aptasensor exhibits excellent specificity and stability. Additionally, its high reliability and applicability are validated by the strong correlation observed between the sensor results and the results obtained using UPLC−MS/MS analysis of real samples. This study offers a low-cost, readily available approach for portable detection of foodborne hazards.

RECENT ADVANCEMENT IN ELECTROCHEMICAL BIOSENSOR BASED ON REDOX ENZYME COMPOSITE MODIFIED ELECTRODE FOR THE DETECTION OF BIOMOLECULES

Recent developments in electrochemical biosensors have resulted in new applications in a variety of disciplines, such as clinical diagnosis, food processing quality control, and environmental monitoring. The electrochemical biosensor is a widely used sensing device that transmits an electrical signal from biological activities. Electrochemical biosensors have led to significant advancements in detecting various biomolecules such as uric acid, glucose, cholesterol, lactate, and DNA, including cancer biomarkers, viruses, and antibodies. An electrode is a vital part of this kind of sensor since it serves as a strong support for immobilizing biomolecules (enzyme, antibody, and nucleic acid) and allowing electron flow. Redox enzymes are the foundation of enzymatic electrochemical biosensors, which use oxidation or reduction reactions to detect a substrate, which is then converted into an electrical signal. Immobilizing enzymes onto solid supports is a common method to enhance the performance of an enzymatic electrochemical biosensor. However, there are some challenges, such as potential loss of enzyme activity, difficulties in maintaining enzyme stability, and issues related to the reproducibility and consistency of enzyme immobilization. This review covers all challenges in enzymatic electrochemical biosensors. Numerous new biosensor platforms are announced each year as researchers look for various electrode materials. Additionally, the researchers should familiarize themselves with the practical methods used in electrode production in order to build a successful biosensor. This review highlights current developments in modifying enzyme-immobilized biosensors for detection of different biomolecules. The article further describes methods of enzyme immobilization and various enzymes with different nanomaterials for the development of novel enzymatic electrochemical biosensors.

Emerging Diagnostic Methods Using Paper-based Electrochemical Biosensors

The development of paper-based electrochemical biosensors has brought about a paradigm shift in the diagnostics industry. These tools provide a portable, affordable, and easy-to-use platform for point-of-care (POC) testing. This has been transformed by the use of electrochemical detection techniques in paper-based analytical devices, which allow for the accurate and insightful assessment of a wide range of chemical analytes. These modified paper-based analytical gadgets have received significant recognition for their inherent benefits in the field of POC. Consequently, the sensitivity and practicality of electrochemical biosensors made of paper-based materials show great promise. They also have several other beneficial features, such as the ability to transport liquids independently, decreased resistance, low manufacturing costs, and environmental friendliness. This study examines the latest developments in paper-based electrochemical biosensing technologies and considers how they might be used in food safety, environmental monitoring, and in developing diagnostic techniques.

Perspective – Leveraging the Versatility of DNA Origami and Electrochemistry for New Sensing Modalities

Abstract Electrochemical biosensors are uniquely positioned to offer real-time in vivo molecular sensing due to their robustness to both biofluids and contaminants found in biofluids, and their adaptability for the detection of different analytes by their use of oligonucleotides or proteins as binding moiety. DNA Origami, the folding of a long DNA scaffold by hundreds of shorter oligonucleotide “staple” strands, allows the construction of nanoscale molecular objects of essentially arbitrary form, flexibility and functionality. We describe work at the intersection of these two fields and their – hopefully – bright future together.

Aptamer-Mediated Electrochemical Detection of SARS-CoV-2 Nucleocapsid Protein in Saliva.

Gold standard detection of SARS-CoV-2 by reverse transcription quantitative PCR (RT-qPCR) can achieve ultrasensitive viral detection down to a few RNA copies per sample. Yet, the lengthy detection and labor-intensive protocol limit its effectiveness in community screening. In view of this, a structural switching electrochemical aptamer-based biosensor (E-AB) targeting the SARS-CoV-2 nucleocapsid (N) protein was developed. Four N protein-targeting aptamers were characterized on an electrochemical cell configuration using square wave voltammetry (SWV). The sensor was investigated in an artificial saliva matrix optimizing the aptamer anchoring orientation, SWV interrogation frequency, and target incubation time. Rapid detection of the N protein was achieved within 5 min at a low nanomolar limit of detection (LOD) with high specificity. Specific N protein detection was also achieved in simulated positive saliva samples, demonstrating its feasibility for saliva-based rapid diagnosis. Further research will incorporate novel signal amplification strategies to improve sensitivity for early diagnosis.

Chitosan/CNDs coated Cu electrode surface has an electrical potential for electrical energy application

Polymers and nanomaterials had been widely applied at electrochemical chemosensor and biosensor. Developing technical energy is still much needed, especially using natural environmental friendly material. Both chitosan of biopolymer and carbon nanodots (CNDs) of nanomaterials are highly studied due to their extraordinary properties. The research focus on chitosan and chitosan/CNDs nanocomposite surface that was applied for electrical energy. Nanocomposite was coated on Cu electrode surface by using electroplating method. The coated electrode was dipped into oil samples. The dipped nanocomposite then was characterized by FTIR, XRD, SEM, and Chemosensor. Nanocomposite structure is still maintain its chemical compound, confirmed by FTIR and XRD, which still maintain amine group; hydroxyl group; and crystalinity of chitosan after CNDs intercoporation. Nanocomposite surface morphology show magnetite particle distribution that spreaded on the surface of electrode for both chitosan and CNDs nanocomposite, which is confirmed by SEM. The free dipping method is based on the sensitive material chitosan/CNDs as a chemosensor; the pressure process on the surface of the chitosan/CNDs sensitive material causes the interaction of metal ions and acid compounds, which involves an iontophoresis process where oil atoms that have been excited in the evaporation process will experience atomic vibrations due to electron transport which then the active groups on the Chemosensor directly absorb and bind metals and acids in oil use a chemisorption process which leads to the transfer of charge from the adsorption particles to the chemosensor surface to fill the holes so that a potential difference occurs in the form of electrical pulses which will then be captured by the Arduino system which will be converted into digital data. This process makes technological energy production in the form of electrical energy faster.

Nanoarchitectonics of Biofunctionalized Hydrogen‐Terminated 2D‐Germanane Heterostructures as Highly Sensitive Biorecognition Transducers: The Case Study of Cocaine Drug

Hydrogen‐terminated 2D‐germanane (2D‐GeH), as one inorganic 2D material akin to graphene, is attracting widespread interest owing to its predicted (opto)electronic properties. Nonetheless, the chemical reactivity of 2D‐GeH requires further exploration to expand its real implementation. Herein, a simple and straightforward bottom‐up biofunctionalization approach is reported aiming at providing the bases toward the robust design of 2D‐GeH‐based biorecognition systems with electrical readout. For this goal, 2D‐GeH has been firstly functionalized with gold nanoparticles (Au‐NPs) via an organometallic approach, followed by the covalent immobilization of a thiolated single‐stranded DNA (ssDNA) aptamer via AuS bond interactions. After an accurate material characterization, the resulting ssDNA/Au@GeH heterostructure is drop‐casted on a fluorine‐doped tin oxide (FTO) electrode for impedimetrically monitoring cocaine as a model drug. Interestingly, the aptamer–cocaine interactions hinder the interfacial electron‐transfer process of the benchmark [Fe(CN)6]3−/4− redox marker with increasing concentration of the cocaine target, leading to a detection limit as low as 4.9 ± 0.1 aM, the lowest one reported in literature by far. Overall, the ssDNA/Au@GeH electrochemical biosensor exhibits outstanding selectivity, specificity, and reproducibility, demonstrating the potential use of 2D‐GeH as an emerging highly sensitive transducer for biosensing applications. The reported method is general and might be simply customized by tailoring the biorecognition component.

A cell-based electrochemical biosensor for the detection of capsaicin

A cell-based electrochemical biosensor for the detection of capsaicin

Ultrasensitive and multiplexed Gastric cancer biomarkers detection with an integrated electrochemical immunosensing platform

Developing immunosensing platforms capable of simultaneously detecting multiple cancer markers is crucial for clinical diagnosis and biomedical research. Here, we introduce a novel dual-mode electrochemical biosensing assay platform capable of detecting two gastric cancer biomarkers: pepsinogen I (PG I) and pepsinogen II (PG II). Methylene blue (MB) and Prussian blue (PB) were used as dual signal sources to label PG I and PG II, respectively. The platform integrates an ARM STM32F411 microcontroller and an AD5941 analog front-end, which not only facilitates cyclic voltammetry (CV) and differential pulse voltammetry (DPV) with efficacy comparable to commercial electrochemical workstations but also offers data collection and synchronous analysis capabilities, allowing simultaneous output of PG I and PGR (PG I/PG II) values. Equipped with an interactive screen for operational control and result display, the immunosensing platform provides linear detection ranges for PG I (5 pg/mL–100 ng/mL) and PG II (50 pg/mL–200 ng/mL), enabling rapid detection within 5 min. It demonstrates excellent sensitivity and selectivity when comparing serum samples from healthy individuals and gastric cancer patients. The dual-marker detection platform significantly enhances early diagnosis and screening of gastric cancer, offering substantial improvements over single-marker assays. Furthermore, this platform shows potential for detecting multiple biomarkers in various diseases, highlighting its utility for biomedical applications.

A NOVEL ELECTROCHEMICAL BIOSENSOR BASED ON CREATININE DEIMINASE FOR CREATININE ANALYSIS

This work presents the development of a new electrochemical biosensor based on creatinine deiminase for the determination of creatinine concentration in biological samples. The optimal method for immobilizing bioselective elements on the electrode surface was selected, specifically the covalent binding of creatinine deiminase in a BSA matrix using glutaraldehyde. The biosensors prepared in this way exhibited the highest sensitivity to creatinine and high reproducibility in the fabrication of biomembranes. The biosensor demonstrated a low limit of detection of creatinine, high signal stability (RSD = 3%), significant storage stability, and a wide linear range, enabling the detection of both normal and pathological creatinine concentrations in biological fluids. The study also investigated the influence of working solution parameters, such as ionic strength, buffer capacity, pH, and protein content, on the biosensor’s performance. The main analytical characteristics of the proposed electrochemical biosensor indicate its potential use for monitoring creatinine concentration in biological samples.

Electrodeposited ZnO Nanostructures on ITO Surfaces: Exploring Their Efficacy for Cholesterol Biosensing Applications

In this study, ZnO nanostructures were prepared by electrochemical anodization of electrodeposited Zn on ITO/glass substrates for cholesterol detection. The efficiency of the developed ZnO nanostructures in the detection of the Cholesterol oxidase (ChOx) enzyme was determined by the cyclic voltammetry method. The XRD and SEM results confirmed the synthesis of ZnO nanostructures prepared by the anodization method with various parameters. The effect of electrodeposition and anodization time on the morphology was observed. Cyclic voltammetry of ZnO/Zn/ITO/glass and Pt/ZnO/Zn/ITO/glass electrodes in electrolytes with various cholesterol concentrations was performed. The detection limit of the obtained Pt/ZnO/Zn/ITO/glass structured electrode was calculated as 0.965x10-3M. The resulting material with a layered structure may have potential applications in electrochemical sensors and biosensors in biomedical applications. In addition to biosensing performance, this study proposes a new approach for the development of ZnO-based biosensors that does not require expensive infrastructure and raw material costs, making it possible to develop high-sensitivity biosensor electrodes with lower detection limits with improvements to be made in future studies.

Role of Exosomes in Salivary Gland Tumors and Technological Advances in Their Assessment.

Backgroud: Salivary gland tumors (SGTs) are rare and diverse neoplasms, presenting significant challenges in diagnosis and management due to their rarity and complexity. Exosomes, lipid bilayer vesicles secreted by almost all cell types and present in all body fluids, have emerged as crucial intercellular communication agents. They play multifaceted roles in tumor biology, including modulating the tumor microenvironment, promoting metastasis, and influencing immune responses. Results: This review focuses on the role of exosomes in SGT, hypothesizing that novel diagnostic and therapeutic approaches can be developed by exploring the mechanisms through which exosomes influence tumor occurrence and progression. By understanding these mechanisms, we can leverage exosomes as diagnostic and prognostic biomarkers, and target them for therapeutic interventions. The exploration of exosome-mediated pathways contributing to tumor progression and metastasis could lead to more effective treatments, transforming the management of SGT and improving patient outcomes. Ongoing research aims to elucidate the specific cargo and signaling pathways involved in exosome-mediated tumorigenesis and to develop standardized techniques for exosome-based liquid biopsies in clinical settings. Conclusions: Exosome-based liquid biopsies have shown promise as non-invasive, real-time systemic profiling tools for tumor diagnostics and prognosis, offering significant potential for enhancing patient care through precision and personalized medicine. Methods like fluorescence, electrochemical, colorimetric, and surface plasmon resonance (SPR) biosensors, combined with artificial intelligence, improve exosome analysis, providing rapid, precise, and clinically valid cancer diagnostics for difficult-to-diagnose cancers.