Search Results (255)

Hepatitis C represents a critical global health crisis, causing approximately 1.4 million deaths annually. Although 98% of cases are treatable, only about 20% of infected individuals know their hepatitis C virus (HCV) status, highlighting the urgent need for rapid and more efficient diagnostic management. Viral genetic material can be detected in serum or plasma within just one week of exposure, making it the most reliable marker and the gold standard for active HCV infection diagnosis. In this study, a biosensor was developed to detect conserved nucleotide sequences of HCV using a 3D surface electrode composed of poly-L-lysine (PLL) and carbon nanotubes (CNTs). PLL is a positively charged biocompatible polymer rich in amine groups, attractive for the immobilization of proteins, DNA, and other biomolecules. PLL was employed to construct a 3D surface with vertically aligned CNTs, achieving a high electron transfer rate. Cyclic voltammetry technique and scanning electron microscopy (SEM) were used to characterize the sensor platform, and analytical responses were measured by differential pulse voltammetry. This HCV biosensor detected the hybridization event by a significant reduction in DPV peaks in the presence of the ferri/ferrocyanide redox probe, without any intercalator agents. DNA responses were observed in phosphate-buffered saline (PBS) and cDNA-spiked serum samples, demonstrating its analytical specificity. These findings represent advances in analytical tools that can effectively address the challenges of timely diagnosis for asymptomatic HCV carriers. Full article

For the first time, the interaction between the amino acid leucine (Leu) and thermally denatured single-stranded (ss) DNA has been demonstrated by applying voltammetry. As a result of interaction, the characteristic peak of ssDNA, due to the oxidation of guanine residues, decreased upon interaction time. The interaction behavior between leucine and ssDNA was also studied with UV–vis spectrophotometry; the obtained results are in good agreement with voltammetric ones. The results of the interaction study were exploited in order to develop a SWV method for the determination of leucine at the ssDNA-modified carbon paste electrode (CPE). Different parameters were tested to optimize the conditions of the determination. The peak of guanine was at around +0.86 V. Linearity was observed in the range of 0.213–4.761 μg/L (r = 0.9990) while LOD equals 0.071 μg/L. The method was applied to a spiked soil sample and gave satisfactory results. Full article

Biosensing plays a vital role in medical diagnostics, environmental monitoring, and food safety, enabling highly sensitive and specific detection of diverse biological and chemical targets. However, conventional biosensing platforms still suffer from limited sensitivity, poor nanoscale resolution, and restricted multiplexed or dynamic detection capabilities. DNA origami, as an emerging bottom-up nanofabrication strategy, enables the construction of programmable nanostructures with high spatial precision. This capability allows the rational arrangement of functional molecules at the nanoscale, thereby offering significant advantages for biosensing applications. Specifically, DNA origami can enhance signal amplification, improve spatial resolution, and enable multiplexed detection under complex conditions. In this review, we provide a systematic overview of recent advances in the application of DNA origami across various classes of biosensors, including microscopy-based biosensors, nanopore biosensors, electrochemical biosensors, fluorescent biosensors, SERS biosensors, and other related biosensors. We aim for this review to advance the development of DNA origami-based biosensing and to provide new insights for researchers working in related fields. Full article

Lignin, the second most abundant biopolymer in nature after cellulose, has attracted attention for its compatibility with carbon-based materials. In this study, lignin-modified single-use pencil graphite electrodes (PGE/LG) were developed for the electrochemical detection of fish sperm DNA (fsDNA), the anticancer drug Mitomycin C (MC), and their interaction. The modified electrodes were characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques. Differential pulse voltammetry (DPV) in ferri/ferrocyanide redox probe solution was employed for signal monitoring. The detection limits were calculated as 2.95 ng/mL for fsDNA between 10¹ and 10⁵ ng/mL and 0.22 pg/mL for MC between 1 and 10⁶ pg/mL. Furthermore, the interaction of DNA with MC was evaluated by DPV and EIS techniques. The cross-linking between MC and the guanine bases of DNA inhibited electron transfer, resulting in a decrease in current response and an increase in charge transfer resistance. These results demonstrate the potential of the PGE/LG platform as a cost-effective, sensitive, and rapid biosensor for DNA detection, anticancer drug analysis, and drug–DNA interaction studies. Full article

Electrochemical biosensors have emerged as a promising tool for the early detection of diseases in oilseed crops such as rapeseed, soybean, and peanut. These biosensors offer high sensitivity, portability, and cost-effectiveness. Timely diagnosis is critical, as many pathogens exhibit latent infection phases or produce invisible metabolic toxins, leading to substantial yield losses before visible symptoms occur. This review summarises recent advances in the field of nanomaterial-assisted electrochemical sensing for oilseed crop diseases, with a particular focus on sensor mechanisms, interface engineering, and biomolecular recognition strategies. The following innovations are highlighted: nanostructured electrodes, aptamer- and antibody-based probes, and signal amplification techniques. These innovations have enabled the detection of pathogen DNA, enzymes, and toxins at ultra-low concentrations. Notwithstanding these achievements, challenges persist, including signal interference from plant matrices, limitations in device miniaturization, and the absence of standardized detection protocols. Future research should explore the potential of AI-assisted data interpretation, the use of biodegradable sensor materials, and the integration of these technologies with agricultural IoT networks. The aim of this integration is to enable real-time, field-deployable disease surveillance. The integration of laboratory innovations with field applications has been demonstrated to have significant potential in supporting sustainable agriculture and strengthening food security through intelligent crop health monitoring. Full article

Early and accurate detection of plant diseases is critical for ensuring global food security and agricultural resilience. Ratoon stunting disease (RSD), caused by the bacterium Leifsonia xyli subsp. xyli (Lxx), is among the most economically significant diseases of sugarcane worldwide. Its cryptic nature—characterized by an absence of visible symptoms—renders timely diagnosis particularly difficult, contributing to substantial undetected yield losses across major sugar-producing regions. Here, we report the development of a potential-induced electrochemical (EC) nanobiosensor platform for the rapid, low-cost, and field-deployable detection of Lxx DNA directly from crude sugarcane sap. This method eliminates the need for conventional nucleic acid extraction and thermal cycling by integrating the following: (i) a boiling lysis-based DNA release from xylem sap; (ii) sequence-specific magnetic bead-based purification of Lxx DNA using immobilized capture probes; and (iii) label-free electrochemical detection using a potential-driven DNA adsorption sensing platform. The biosensor shows exceptional analytical performance, achieving a detection limit of 10 cells/µL with a broad dynamic range spanning from 10⁵ to 1 copy/µL (r = 0.99) and high reproducibility (SD < 5%, n = 3). Field validation using genetically diverse sugarcane cultivars from an inoculated trial demonstrated a strong correlation between biosensor signals and known disease resistance ratings. Quantitative results from the EC biosensor also showed a robust correlation with qPCR data (r = 0.84, n = 10, p < 0.001), confirming diagnostic accuracy. This first-in-class EC nanobiosensor for RSD represents a major technological advance over existing methods by offering a cost-effective, equipment-free, and scalable solution suitable for on-site deployment by non-specialist users. Beyond sugarcane, the modular nature of this detection platform opens up opportunities for multiplexed detection of plant pathogens, making it a transformative tool for early disease surveillance, precision agriculture, and biosecurity monitoring. This work lays the foundation for the development of a universal point-of-care platform for managing plant and crop diseases, supporting sustainable agriculture and global food resilience in the face of climate and pathogen threats. Full article

Infectious diseases poses a growing public health challenge. The COVID-19 pandemic has further emphasized the urgent need for rapid, accessible diagnostics. This study presents the development of an integrated, flexible point-of-care (POC) diagnostic system for the rapid detection of Corynebacterium diphtheriae, the pathogen responsible for diphtheria. The system comprises a microfluidic polymerase chain reaction (micro-PCR) device and an electrochemical DNA biosensor, both fabricated on flexible substrates. The micro-PCR platform offers rapid DNA amplification overcoming the time limitations of conventional thermocyclers. The biosensor utilizes specific molecular recognition and an electrochemical transducer to detect the amplified DNA fragment, providing a clear and direct indication of the pathogen’s presence. The combined system demonstrates the effective amplification and detection of a gene fragment from a toxic strain of C. diphtheriae, chosen due to its increasing incidence. The design leverages lab-on-a-chip (LOC) and microfluidic technologies to minimize reagent use, reduce cost, and support portability. Key challenges in microsystem design—such as flow control, material selection, and reagent compatibility—were addressed through optimized fabrication techniques and system integration. This work highlights the feasibility of using flexible, integrated microfluidic and biosensor platforms for the rapid, on-site detection of infectious agents. The modular and scalable nature of the system suggests potential for adaptation to a wide range of pathogens, supporting broader applications in global health diagnostics. The approach provides a promising foundation for next-generation POC diagnostic tools. Full article

DNA methylation, as a critical epigenetic modification, plays a central role in gene regulation and has emerged as a powerful biomarker for early disease diagnostics, particularly in cancer. Owing to the limitations of traditional bisulfite sequencing—such as high cost, complexity, and chemical degradation—electrochemical biosensors have gained substantial attention as promising alternatives. This review summarizes recent advancements in electrochemical platforms for bisulfite-free detection of DNA methylation, encompassing direct oxidation strategies, enzyme-assisted recognition (e.g., restriction endonucleases and methyltransferases), immunoaffinity-based methods, and a variety of signal amplification techniques such as rolling circle amplification and catalytic hairpin assembly. Additional approaches, including strand displacement, magnetic enrichment, and adsorption-based detection, are also discussed. These systems demonstrate exceptional sensitivity, often down to the attomolar or femtomolar level, as well as high selectivity, reproducibility, and suitability for real biological matrices. The integration of nanomaterials and redox-active probes further enhances analytical performance. Importantly, many of these biosensing platforms have been validated using clinical samples, reinforcing their translational relevance. The review concludes by outlining current challenges and future directions, emphasizing the potential of electrochemical biosensors as scalable, cost-effective, and minimally invasive tools for real-time epigenetic monitoring and early-stage disease diagnostics. Full article

Prostate cancer is the second leading cause of cancer-related deaths among men in the United States. The early detection of aggressive forms is critical. Current diagnostic methods, including PSA testing and biopsies, are invasive and often yield false results. MicroRNA-141 (miRNA-141) has emerged as a promising non-invasive biomarker due to its elevated levels in the urine of patients with metastatic prostate cancer. Here, a low-cost, paper-based electrochemical biosensor for the sensitive detection of miRNA-141 in synthetic urine is reported. The device employs inkjet-printed gold electrodes on photopaper, functionalized with thiolated single-stranded DNA-141 capture probes for specific target recognition. The biosensor achieves a sensitivity of 78.66 fM µA⁻¹ cm⁻² and a linear detection range of 1 fM to 100 nM, encompassing clinically relevant concentrations of miRNA-141 found in patients with metastatic prostate cancer. A low limit of detection of 2.15 fM, strong selectivity against non-target sequences, and a rapid response time of 15 min further highlight the diagnostic potential of the device. This platform represents a significant advancement in the development of point-of-care diagnostic tools for prostate cancer and is readily adaptable for detecting other disease-specific miRNAs through simple probe modification. As such, it holds broad promise for accessible, early-stage cancer detection and longitudinal disease monitoring in diverse clinical settings. Full article

Titanium dioxide (TiO₂) is one of the most widely produced nanomaterials. Many products contain nanoparticles because they have various technological, medical, and economic benefits. However, the presence of nanoparticles in the environment has a negative impact on public health. Due to the presence of TiO₂ NPs in food, food packaging, and drinking water, they can easily enter the human gastrointestinal tract (GIT), which includes environments with different pH values. These pH changes can affect the stability, dispersion, and toxicity of nanomaterials. Our experiments aimed to monitor the effect of TiO₂ NPs incubated at a pH similar to the GIT values on DNA structure. DNA damage was monitored using a DNA biosensor and a biosensing approach with electrochemical voltammetric detection. Cyclic voltammetry (CV) detected damage to DNA/GCE biosensors of up to 10%. The best way to monitor the genotoxicity of TiO₂ NPs on DNA structure was the biosensing approach, which changes in the redox indicator current response detected by differential pulse voltammetry (DPV) up to 47.6%. The highest effect of TiO₂ was observed for guanine residues at pH 8.0. The results were confirmed by UV–vis spectrophotometry and hyperchromic and bathochromic spectral shifts. Full article

Two-dimensional nanomaterials (2DNMs) exhibit significant potential for the development of functional and specifically targeted biosensors, owing to their unique planar nanosheet structures and distinct physical and chemical properties. Biomodification and biomimetic synthesis offer green and mild approaches for the fabrication of multifunctional nanohybrids with enhanced catalytic, fluorescent, electronic, and optical properties, thereby expanding their utility in constructing high-performance biosensors. In this review, we present recent advances in the synthesis of 2DNM-based nanohybrids via both biomodification and biomimetic strategies for biosensor applications. We discuss covalent and non-covalent biomodification methods involving various biomolecules, including peptides, proteins, DNA/RNA, enzymes, biopolymers, and bioactive polysaccharides. The engineering of biomolecule–nanomaterial interfaces for the creation of biomodified 2DNM-based nanohybrids is also explored. Furthermore, we summarize the biomimetic synthesis of 2DNM-based bio–nanohybrids through pathways such as bio-templating, biomolecule-directed self-assembly, biomineralization, and biomimetic functional integration. The potential applications of these nanohybrids in diverse biosensing platforms—including colorimetric, surface plasmon resonance, electrochemical, fluorescence, photoelectrochemical, and integrated multimodal biosensors—are introduced and discussed. Finally, we analyze the opportunities and challenges associated with this rapidly developing field. We believe this comprehensive review will provide valuable insights into the biofunctionalization of 2DNMs and guide the rational design of advanced biosensors for diagnostic applications. Full article

Electrochemical biosensors have attracted widespread attention from researchers due to their simple and rapid operation. Recent advancements in nanobiotechnology have further enhanced their performance, with nanomaterials like graphene, carbon nanotubes, and metal nanoparticles being widely used as carriers for immobilizing enzymes, cells, and DNA molecules. These materials improve stability, sensitivity, and selectivity, making biosensors more effective. This article reviews the introduction, principles, and classification of enzyme-based electrode sensors, as well as their research and application progress in the detection of food risk factors (including foodborne pathogens, biotoxins, drug residues, food additives, allergens, etc.). It also explores future prospects, including advancements in nanotechnology and enzyme immobilization techniques, highlighting their potential in food safety and beyond. Full article

Infectious bronchitis virus (IBV) is an enveloped, positive-sense, single-stranded RNA virus belonging to the genus Gammacoronavirus. It primarily infects avian species, causing respiratory and renal disease and irreversible damage to the oviduct, which can lead to high mortality rates in chickens. The lack of rapid and reliable diagnostic tools for on-farm IBV detection hampers timely disease management and control measures. The introduction of DNA biosensors offers a promising approach for the sensitive and specific detection of IBV, facilitating rapid identification and intervention. In this study, an electrochemical DNA biosensor with a multi-walled carbon nanotube (MWCNT)-modified gold electrode was developed for IBV detection. The biosensor targeted the target-specific 5′ untranslated region (5′-UTR) of the IBV genome. Under optimal conditions, the immobilization and hybridization efficiencies were evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), with methylene blue as a redox indicator. The developed DNA biosensor demonstrated a dynamic detection range from 2.0 × 10⁻¹² to 2.0 × 10⁻⁵ mol L⁻¹, with a limit of detection (LOD) of 2.6 nM and a limit of quantification (LOQ) of 0.79 nM. Validation using a small subset of clinical samples, including crude complementary DNA, and polymerase chain reaction products, showed high recovery rates ranging from 95.41% to 99.55%. While these findings highlight the potential of the proposed DNA biosensor as an innovative diagnostic tool for IBV detection, this study remains a proof of concept. However, further validation using a large number of clinical samples is essential to assess its feasibility, robustness, and practical application in a real-world farm setting Full article

The development of electrochemical DNA biosensors occurred by applying different organically coated Mn-NPs such as MnCO₃@OAm, MnCO₃@TEG and MnO₂/Mn₂O₃@TEG, as well as naked MnCO₃ NPs (where OAm = oleylamine and TEG = tetraethylene glycol). The detection performances of PGEs were modified with different types of Mn-NPs, according to the guanine signal magnitudes obtained after double-stranded DNA (dsDNA) or single-stranded DNA (ssDNA) immobilization at these surfaces. DNA interaction studies were realized using UV-vis, circular dichroism (CD), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) techniques. In addition, a 3- to 5.4-fold increase in guanine response in the presence of dsDNA and a 2.3-fold increase in the presence of ssDNA were obtained with the developed biosensor. The increased signals in DNA immobilization at the electrode surfaces modified with Mn-NPs compared to bare PGE clearly show that the modification of Mn-NPs increases the electroactive surface area of the electrode. The detection limit (LOD) of dsDNA was calculated as 7.86 μg·L⁻¹ using the MnO₂/Mn₂O₃@TEG type of the Mn-NP-modified biosensor, while the detection limit of ssDNA was calculated as 3.49 μg·L⁻¹ with the MnCO₃@OAm type Mn-NP-modified biosensor. The proposed sensor was applied to a human DNA sample where the amount of dsDNA extract was found to be 0.62 ± 0.03 mg·L⁻¹ after applying the MnO₂/Mn₂O₃@TEG type of Mn-NP-modified biosensor. Full article

Biosensing shows promise in detecting cancer, renal disease, and other illnesses. Depending on their transducing processes, varieties of biosensors can be divided into electrochemical, optical, piezoelectric, and thermal biosensors. Advancements in material production techniques, enzyme/protein designing, and immobilization/conjugation approaches can yield novel nanoparticles with further developed functionality. Research in cutting-edge biosensing with multifunctional nanomaterials, and the advancement of practical biochip plans utilizing nano-based sensing material, are of current interest. The miniaturization of electronic devices has enabled the growth of ultracompact, compassionate, rapid, and low-cost sensing technologies. Some sensors can recognize analytes at the molecule, particle, and single biological cell levels. Nanomaterial-based sensors, which can be used for biosensing quickly and precisely, can replace toxic materials in real-time diagnostics. Many metal-based NPs and nanocomposites are favorable for biosensing. Through direct and indirect labeling, metal-oxide NPs are extensively employed in detecting metabolic disorders, such as cancer, diabetes, and kidney-disease biomarkers based on electrochemical, optical, and magnetic readouts. The present review focused on recent developments across multiple biosensing modalities using metal/metal-oxide-based NPs; in particular, we highlighted the specific advancements of biosensing of key nanomaterials like ZnO, CeO₂, and TiO₂ and their applications in disease diagnostics and environmental monitoring. For example, ZnO-based biosensors recognize uric acid, glucose, cholesterol, dopamine, and DNA; TiO₂ is utilized for SARS-CoV-19; and CeO₂ for glucose detection. Full article