Ultra-sensitive electrochemical detection of oxidative stress biomarker 8-hydroxy-2′-deoxyguanosine with poly (L-arginine)/graphene wrapped Au nanoparticles modified electrode

Electrochemical approaches based on micro- and nanomaterials for diagnosing oxidative stress

This review article comprehensively discusses the various electrochemical approaches for measuring and detecting oxidative stress biomarkers and enzymes, particularly reactive oxygen/nitrogen species, highly reactive chemical molecules, which are the byproducts of normal aerobic metabolism and can oxidize cellular components such as DNA, lipids, and proteins. First, we address the latest research on the electrochemical determination of reactive oxygen species generating enzymes, followed by detection of oxidative stress biomarkers, and final determination of total antioxidant activity (endogenous and exogenous). Most electrochemical sensing platforms exploited the unique properties of micro- and nanomaterials such as carbon nanomaterials, metal or metal oxide nanoparticles (NPs), conductive polymers and metal-nano compounds, which have been mainly used for enhancing the electrocatalytic response of sensors/biosensors. The performance of the electroanalytical devices commonly measured by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in terms of detection limit, sensitivity, and linear range of detection is also discussed. This article provides a comprehensive review of electrode fabrication, characterization and evaluation of their performances, which are assisting to design and manufacture an appropriate electrochemical (bio)sensor for medical and clinical applications. The key points such as accessibility, affordability, rapidity, low cost, and high sensitivity of the electrochemical sensing devices are also highlighted for the diagnosis of oxidative stress. Overall, this review brings a timely discussion on past and current approaches for developing electrochemical sensors and biosensors mainly based on micro and nanomaterials for the diagnosis of oxidative stress.

Label free flexible electrochemical DNA biosensor for selective detection of Shigella flexneri in real food samples

An effective tool for early-stage selective detection of the foodborne bacterial pathogen Shigella flexneri (S. flexneri) is essential for diagnosing infectious diseases and controlling outbreaks. Here, a label-free electrochemical DNA biosensor for monitoring S. flexneri is developed. To fabricate the biosensor, detection probe (capture probe) is immobilized on the surface of poly melamine (P-Mel) and poly glutamic acid (PGA), and disuccinimidyl suberate (DSS) functionalized flexible indium tin oxide (ITO) electrode. Anthraquinone-2-sulfonic acid monohydrate sodium salt (AQMS) is used as a signal indicator for the detection of S. flexneri. The proposed DNA biosensor exhibits a wide dynamic range with concentration of the targets ranging from 1 × 10^-6 to 1 × 10^-21 molL^-1 with a limit of detection (LOD) of 7.4 × 10^-22 molL^-1 in the complementary linear target of S. flexneri, and a detection range of 8 × 10¹⁰-80 cells/ml with a LOD of 10 cells/ml in real S. flexneri sample. The proposed flexible biosensor provides high specificity for the detection of S. flexneri compared to other target signals such as discrete base mismatches and different bacterial species. The developed biosensor displayed excellent recoveries in detecting S. flexneri in spiked food samples. Therefore, the proposed biosensor can serve as a model methodology for the detection of other pathogens in a broad span of industries.

Electrochemical Biosensor Based on l-Arginine and rGO-AuNSs Deposited on the Electrode Combined with DNA Probes for Ultrasensitive Detection of the Gastric Cancer-Related PIK3CA Gene of ctDNA

Gene biomarkers of circulating tumor DNA (ctDNA) in liquid biopsies have been explored for use in the precise diagnosis of tumors. There is a great clinical need to realize the ultrasensitive detection of gene biomarkers in ctDNA. Here we reported that an ultrasensitive label-free biosensor was developed for the detection of the gastric cancer-related PIK3CA gene of ctDNA in peripheral blood. The polymeric l-arginine and graphene oxide-wrapped gold nanostars (rGO-AuNSs) were prepared and deposited on the glass electrode. The capturing DNA probes for the PIK3CA gene were prepared and successfully immobilized on the rGO-AuNS-modified electrode surface via π-π interaction among the rGO-AuNS composites and DNA probes. The resultant electrochemical sensor was effectively applied to detect the PIK3CA gene of ctDNA via the hybridization between the capturing DNA probe and ctDNA, the result of which showed that the biosensor exhibited desirable sensitivity, stability, and a wider dynamic response in a ctDNA concentration range from 1.0 × 10^-20 to 1.0 × 10^-10 M (R² = 0.997). Moreover, the low limit of detection of 1.0 × 10^-20 M (S/N = 3) indicates the biosensor owns satisfactory detection sensitivity. Fourteen PIK3CA genes and two PIK3CA gene mutations were detected in 60 clinical ctDNA samples of gastric cancer patients by using the developed biosensor. In conclusion, this ultrasensitive label-free electrochemical biosensor possesses a significant application prospect in the detection of the PIK3CA gene in ctDNA and in early screening for gastric cancer in the near future.

Potential roles of genistein in polycystic ovary syndrome: A comprehensive systematic review

Polycystic ovary syndrome (PCOS) is one of the most prevalent polygenic endocrine disorders in reproductive-age women. Genistein is a soy-isolated phytoestrogen and isoflavone with antioxidant, anti-inflammatory, estrogenic, and antineoplastic activity. This systematic review aimed to investigate the therapeutic effects and mechanisms of actions of genistein in PCOS. The present study was conducted according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. We searched PubMed, Scopus, Embase, and Google Scholar databases up to February 2022 using relative keywords. Studies published in English evaluated genistein's effects on PCOS, and its related symptoms were considered. Out of 298 records screened, only 13 articles met the inclusion criteria: Nine animal and 4 human studies. The results of the current study indicated that genistein supplementation may effectively improve PCOS-related symptoms by decreasing insulin resistance and anthropometric indices, improving ovarian morphology and regulating reproductive hormones, and reducing oxidative stress and inflammation by influencing biological pathways. According to the current literature, genistein may diminish the dues of PCOS. Therefore, this study shows that genistein can be considered an effective agent. in reducing the complications of PCOS. However, further studies are recommended for a broad conclusion on the exact mechanism of genistein in PCOS patients.

Graphene-Based Biosensors for Molecular Chronic Inflammatory Disease Biomarker Detection

Chronic inflammatory diseases, such as cancer, diabetes mellitus, stroke, ischemic heart diseases, neurodegenerative conditions, and COVID-19 have had a high number of deaths worldwide in recent years. The accurate detection of the biomarkers for chronic inflammatory diseases can significantly improve diagnosis, as well as therapy and clinical care in patients. Graphene derivative materials (GDMs), such as pristine graphene (G), graphene oxide (GO), and reduced graphene oxide (rGO), have shown tremendous benefits for biosensing and in the development of novel biosensor devices. GDMs exhibit excellent chemical, electrical and mechanical properties, good biocompatibility, and the facility of surface modification for biomolecular recognition, opening new opportunities for simple, accurate, and sensitive detection of biomarkers. This review shows the recent advances, properties, and potentialities of GDMs for developing robust biosensors. We show the main electrochemical and optical-sensing methods based on GDMs, as well as their design and manufacture in order to integrate them into robust, wearable, remote, and smart biosensors devices. We also describe the current application of such methods and technologies for the biosensing of chronic disease biomarkers. We also describe the current application of such methods and technologies for the biosensing of chronic disease biomarkers with improved sensitivity, reaching limits of detection from the nano to atto range concentration.

Review on oxidative stress relation on COVID-19: Biomolecular and bioanalytical approach

COVID-19 disease has put life of people in stress worldwide from many aspects. Since the virus has mutated in absolutely short period of time the challenge to find a suitable vaccine has become harder. Infection to COVID-19, especially at severe life threatening states is highly dependent on the strength of the host immune system. This system is partially dependent on the balance between oxidative stress and antioxidant. Besides, this virus still has unknown mechanism of action companied by a probable commune period. From another hand, some reactive oxygen species (ROS) levels can be helpful on the state determination of the disease. Thus it could be possible to use modern bioanalytical techniques for their detection and determination, which could indicate the disease state at the golden time window since they have the potential to show whether specific DNA, RNA, enzymes and proteins are affected. This also could be used as a preclude study or a reliable pathway to define the best optimized time of cure beside effective medical actions. Herein, some ROS and their relation with SARS-CoV-2 virus have been considered. In addition, modern bioelectroanalytical techniques on this approach from quantitative and qualitative points of view have been reviewed.

Bioaccumulation and detoxification of trivalent arsenic by Achromobacter xylosoxidans BHW-15 and electrochemical detection of its transformation efficiency

Arsenotrophic bacteria play an essential role in lowering arsenic contamination by converting toxic arsenite [As (III)] to less toxic and less bio-accumulative arsenate [As (V)]. The current study focused on the qualitative and electrocatalytic detection of the arsenite oxidation potential of an arsenite-oxidizing bacteria A. xylosoxidans BHW-15 (retrieved from As-contaminated tube well water), which could significantly contribute to arsenic detoxification, accumulation, and immobilization while also providing a scientific foundation for future electrochemical sensor development. The minimum inhibitory concentration (MIC) value for the bacteria was 15 mM As (III). Scanning Electron Microscopy (SEM) investigation validated its intracellular As uptake capacity and demonstrated a substantial association with the MIC value. During the stationary phase, the strain’s As (III) transformation efficiency was 0.0224 mM/h. Molecular analysis by real-time qPCR showed arsenite oxidase (aioA) gene expression increased 1.6-fold in the presence of As (III) compared to the untreated cells. The immobilized whole-cell also showed As (III) conversion up to 18 days. To analyze the electrochemical oxidation in water, we developed a modified GCE/P-Arg/ErGO-AuNPs electrode, which successfully sensed and quantified conversion of As (III) into As (V) by accepting electrons; implying a functional As oxidase enzyme activity in the cells. To the best of our knowledge, this is the first report on the electrochemical observation of the As-transformation mechanism with Achromobactersp. Furthermore, the current work highlighted that our isolate might be employed as a promising candidate for arsenic bioremediation, and information acquired from this study may be helpful to open a new window for the development of a cost-effective, eco-friendly biosensor for arsenic species detection in the future.

Genistein exhibits therapeutic potential for PCOS mice via the ER-Nrf2-Foxo1-ROS pathway

Polycystic ovarian syndrome (PCOS) is a complex endocrinopathy in women of reproductive age and the main cause of female infertility, but there is no universal drug for PCOS therapy. As a predominant dietary isoflavone present in soybeans, genistein (GEN) possesses estrogenic and antioxidative properties, but limited information is available regarding its therapeutic potential and underlying molecular mechanism in PCOS. In this study, we found that GEN might restore the estrous cycle of PCOS mice and ameliorate the elevation of circulating T, AMH and LH levels as well as LH/FSH ratios along with reduced cystic follicles, indicating the importance of GEN in PCOS therapy. Meanwhile, GEN improved the ovarian secretion function of PCOS mice and attenuated oxidative damage of the ovary through enhancing its antioxidant capability dependent on ER. Supplementation of GEN improved the defect of the ATP level and mitochondrial membrane potential, indicating the significance of GEN in preventing mitochondrial dysfunction. Further analysis demonstrated that GEN via ER heightened the expression of Nrf2 and Foxo1 whose blockage antagonized the defence of GEN on the secretory and mitochondrial functions of ovarian granulosa cells followed by the limited antioxidant capability and increased intracellular ROS level. Moreover, nuclear translocation and transcriptional activity of Nrf2 presented a notable enhancement after exposure to GEN. Addition of the Nrf2 inhibitor ML385 hampered the GEN induction of Foxo1. Nrf2 might directly bind to the antioxidant response element of the Foxo1 promoter region. Collectively, GEN might exhibit therapeutic potential for PCOS mice via the ER-Nrf2-Foxo1-ROS pathway.

Nanostructured material-based electrochemical sensing of oxidative DNA damage biomarkers 8-oxoguanine and 8-oxodeoxyguanosine: a comprehensive review

Oxidative DNA damage plays an important role in the pathogenesis of various diseases. Among oxidative DNA lesions, 8-oxoguanine (8-oxoG) and its corresponding nucleotide 8-oxo-2'-deoxyguanosine (8-oxodG), the guanine and deoxyguanosine oxidation products, have gained much attention, being considered biomarkers for oxidative DNA damage. Both 8-oxoG and 8-oxodG are used to predict overall body oxidative stress levels, to estimate the risk, to detect, and to make prognosis related to treatment of cancer, degenerative, and other age-related diseases. The need for rapid, easy, and low-cost detection and quantification of 8-oxoG and 8-oxodG biomarkers of oxidative DNA damage in complex samples, urine, blood, and tissue, caused an increasing interest on electrochemical sensors based on modified electrodes, due to their high sensitivity and selectivity, low-cost, and easy miniaturization and automation. This review aims to provide a comprehensive and exhaustive overview of the fundamental principles concerning the electrochemical determination of the biomarkers 8-oxoG and 8-oxodG using nanostructured materials (NsM), such as carbon nanotubes, carbon nanofibers, graphene-related materials, gold nanomaterials, metal nanoparticles, polymers, nanocomposites, dendrimers, antibodies and aptamers, and modified electrochemical sensors.

Recent Biosensors for Detection of Antibiotics in Animal Derived Food

Antibiotics are extensively employed as bacteriostatic agents for fighting against microbial infection in animals. However, inappropriate doses of antibiotic drugs may result in antibiotic residues in food of animal origin and may cause various side effects on human health. Moreover, the transferor of antibiotic-resistant bacteria to humans through the food chain may induce serious health hazards. Hence, it is vital to develop sensitive and selective methods for rapid screening and regular monitoring of antibiotic residues in animal-derived foods. The conventional different chromatographic and spectroscopic techniques are time-consuming, expensive and require skilled personnel. To overcome such limitations, biosensors have emerged as an innovative approach recently and integrated with nanotechnologies for sensitive, rapid and on-site monitoring of different antibiotic residues in animal origin foods. This mini-review aims to give an overview of the currently available biosensing techniques to detect antibiotic residue in foods.

Poly(sulfosalicylic acid)-functionalized gold nanoparticles for the detection of tetrabromobisphenol A at pM concentrations

Developing a sensitive, simple and fast sensing system for 3,3',5,5'-tetrabromobisphenol A (TBBPA) is important because of its ubiquitousness and high toxicity. In this work, a gold nanoparticles (AuNPs) and poly(sulfosalicylic acid) (PSSA) composite film (AuNPs-PSSA) is fabricated in-situ on an electrode surface via cyclic voltammetry scanning. The characterization via scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray (EDX) analysis and Fourier transform infrared (FTIR) spectroscopy indicate that the PSSA film is homogeneously decorated with AuNPs, and a highly uniform and thin composite film is obtained. Electrochemical tests reveal that the AuNPs-PSSA film exhibits larger active surface area, lower charge transfer resistance and higher accumulation efficiency toward TBBPA than single AuNPs and PSSA film. As a result, the oxidation signals and sensing sensitivity of TBBPA are significantly enhanced on the surface of the AuNPs-PSSA. The developed TBBPA sensing platform using AuNPs-PSSA composite film, with low detection limit (25 pM) and wide linear range (0.1-10 nM), is successfully utilized to measure TBBPA level in wastewater samples. The results are highly consistent with those that obtained from high-performance liquid chromatography. The preparation and reusability of the TBBPA sensor can be automatically achieved through CV scanning, providing a promising on-line monitoring system for wastewater samples.

Detection of xanthine in food samples with an electrochemical biosensor based on PEDOT:PSS and functionalized gold nanoparticles

An innovative biosensor assembly relying on glassy carbon electrodes modified with nanocomposites consisting of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a host matrix with functionalized gold nanoparticles (GCE/PEDOT:PSS-AuNPs) is presented for the selective and sensitive detection of xanthine (XA). The developed sensor was successfully applied for the quantification of XA in the presence of significant interferents like hypoxanthine (HXA) and uric acid (UA). Different spectroscopy and electron microscopy analyses were done to characterize the as-prepared nanocomposite. Calibration responses for the quantification of XA was linear from 5.0 × 10⁻⁸ to 1.0 × 10⁻⁵ M (R² = 0.994), with a detection limit as low as 3.0 × 10⁻⁸ (S/N = 3). Finally, the proposed sensor was applied for the analyses of XA content in commercial fish and meat samples and satisfactory recovery percentage was obtained.

An innovative biosensor with glassy carbon electrodes modified with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate nanocomposites as a host matrix with functionalized gold nanoparticles for the selective and sensitive detection of xanthine.

Electrochemical biomolecule detection based on the regeneration of high-efficiency cascade catalysis for bifunctional nanozymes

Herein, the reusable high-efficiency cascade amplification of nanozymes was obtained for electrochemical analysis of 8-OHdG based on reversible capture/release of electronic media in a fast and green manner.

Progress in cancer biomarkers monitoring strategies using graphene modified support materials

Cancer is the one of the fatal and dreaded disease responsible for huge number of morbidity and mortality across the globe. It is expected that the global burden will increase to 21.7 million fresh cancer cases as compared to present estimate of 18.1 million cancer cases in addition to nearly 9.6 million cancer deaths worldwide. In response to cancerous or certain benign conditions; specific type of tumor or cancer markers (biomarkers) are produced at much higher levels which are secreted into the urine, blood, stool, tumor or other tissues. Therefore, the efficient and early detection of cancer biomarkers is necessary which can offer a reliable way for cancer patient screening and diagnosis. This process not only helps in the evaluation of pathogenic processes but also the prognosis of different cancers and pharmacological responses to therapeutic interventions are secured. Over the past several years, electrochemical detection methods have proved to be the most attractive methods among many, due to the advantages, such as simple instrumentation, portability, low cost and high sensitivity. Furthermore, the modifications of these electrochemical immunosensors by utilizing various types of nanomaterials enable these systems to detect trace amount of target tumor markers. Hence, herein, we intend to review the selective works on electrochemical detection of various biomarkers using wide range of nanomaterials with a particular focus on graphene.

Electrochemical Detection of Melamine by Using Reduced Graphene Oxide-Copper Nanoflowers Modified Glassy Carbon Electrode

In this work, a robust and reliable electrochemical sensor was developed for sensitive detection of non-electroactive melamine (MEL) using a modified glassy carbon electrode with ascorbic acid (AA) as the active recognition element. To increase the current signal of AA, the working electrode was successively modified with l-arginine (l-Arg) and reduced graphene oxide-copper nanoflower composite. The voltammetry measurements denoted that the hydrogen bonding was formed between AA and MEL. Using the optimum conditions, the proposed enhanced sensor can detect MEL concentrations ranging from 10 × 10^-9 to 9.0 × 10^-8 M with a detection limit of 5.0 × 10^-9 M that is proportional to the decrease of AA in the anodic peak current. Finally, the proposed sensor was successfully applied for the determination of MEL in commercial infant milk samples and good recovery values were obtained.

A novel electrochemical sensor for determination of DNA damage biomarker (8-hydroxy-2'-deoxyguanosine) in urine using sonochemically derived graphene oxide sheets covered zinc oxide flower modified electrode

To explore a novel and multi-layer based graphene oxide covered zinc oxide nanoflower (ZnO NFs@GOS) as a modified electrode materials by sonochemical technique (40 kHz, 300 W). Herein, novel nanocomposite is successfully characterized by various characterization analysis (FESEM, HRTEM, XRD, XPS and (EIS) electrochemical impedance spectroscopy) and employed as high sensitive modified electrode (ZnO NFs@GOS nanocomposite) for the electrochemical determination of biomarker. 8-hydroxy-2'-deoxyguanosine (8-HDG) is one of the important cancer and oxidative stress biomarker. The results demonstrated that the ZnO NFs@GOS modified SPCE reveal well-defined electro-oxidation peak at 0.36 V (vs. Ag/AgCl). The high sensitive properties of the optimized flower like modified electrode are because of the excellent synergistic effect of the ZnO flower and the graphene oxide nanosheets, as evidenced by a superior bio-sensing performance. The nanocomposite fabricated modified biosensor was facilitating the analysis of 8-HDG in the concentration ranges of 0.05-536.5 µM with a low detection limit is 8.67 nM. The ZnO NFs@GOS modified sensor can also employed for the determination of 8-HDG in human urine samples, promising its application towards the quantification of cancer biomarker in biological samples.

Detection of 8-Hydroxy-2'-Deoxyguanosine Biomarker with a Screen-Printed Electrode Modified with Graphene

In this work we present the preparation of graphene material by exfoliation of graphite rods via pulses of current in electrolyte, containing a mixture of boric acid (0.05 M) and sodium chloride (0.05 M). The material was morphologically and structurally characterized by SEM/TEM/HR-TEM, XRD and FTIR techniques. TEM investigation of graphene flakes deposited onto carbon-coated grids allowed the visualization of thin and transparent regions, attributed to few-layer graphene (FLG), as well as thick and dark regions attributed to multi-layer graphene (MLG). The mixed composition of the material was additionally confirmed by XRD, which further indicated that the amount of FLG within the sample was around 83%, while MLG was around 17%. The performance of a screen-printed electrode (SPE) modified with graphene (SPE-Gr) was tested for 8-hydroxy-2′-deoxyguanosine detection. The graphene-modified electrode had a higher sensitivity in comparison with that of SPE, both in standard laboratory solutions (phosphate buffered saline—PBS) and in human saliva.

Reduced Graphene Oxide-Conjugated Urchin-Like NiCo2O4 Nanostructures for Individual Detection of o-Nitro and p-Amino Phenol

This work introduced a facile synthesis method of reduced graphene oxide-conjugated urchin-like NiCo2O4 nanostructures via a simple, cost-effective, and environmental-friendly one-pot hydrothermal method. The as-prepared rGO-NiCo2O4 nanocomposites were used to fabricate 3-aminopropyltriethoxysilane-modified glassy carbon electrode (GCE/APTES/rGO-NiCo2O4) for ultrasensitive electrochemical detection of o-nitro (o-NP) and p-amino (p-AP) phenols. The structure and morphology of the nanocomposite were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Electrochemical experiments revealed that the nanocomposite exhibited remarkable electrochemical performances. A linear relationship is observed with the differential pulse voltammetry experiment between the peak currents and the concentrations in the ranges of 5.0 × 10-9 to 5.0 × 10-7 M (R 2 = 0.996) and 1.0 × 10-6 to 2.5 × 10-5 M (R 2 = 0.992) for o-NP and of 1.0 × 10-8 to 5.0 × 10-7 M (R 2 = 0.996) and 1.0 × 10-6 to 1.0 × 10-4 M (R 2 = 0.987) for p-AP. The calculated detection limits (S/N = 3) are 5.0 × 10-9 M and 1.0 ×10-8 M for o-NP and p-AP, respectively. Furthermore, a very high recovery percentage is obtained with the proposed sensor after successful application in the determination of target analytes in tap water samples.

Controlling parameters and characteristics of electrochemical biosensors for enhanced detection of 8-hydroxy-2'-deoxyguanosine

This work discusses the parameters and characteristics required on the development of a scalable and reliable electrochemical sensor board for detecting 8-hydroxy-2′-deoxyguanosine (8-OHdG), an oxidative stress biomarker for diabetic nephropathy, cancer and Parkinson’s disease. We used Printed Circuit Board (PCB) technology to make a precise, low-cost bare sensor board. ZnO nanorods (NRs) and ZnO NRs: reduced graphene oxide (RGO) composites were used as a pathway for antibody immobilization on the working electrode (WE). The parameters and characteristics of the WE were controlled for enhancing the quality of the electrochemical sensor board. Thickness of the gold and the presence of ZnO NRs or their composite on the WE have influence on charge transference process and reproducibility of the sensor board. The amount of the antibody, and its incubation period are crucial to avoid saturation of the sites during immobilization step and reduce the cost of the sensor. Our ZnO NRs-based electrochemical sensor board showed high sensitivity and selectivity to 8-OHdG with detection capacity in the range of 0.001–5.00 ng.mL⁻¹. The successful application of our immunosensor to detect 8-OHdG in urine was evidenced.