Magnetic nanoparticle decorated graphene based electrochemical nanobiosensor for H2O2 sensing using HRP

Electrochemical Detection of a Breast Cancer Biomarker with an Amine-Functionalized Nanocomposite Pt-Fe3O4-MWCNTs-NH2 as a Signal-Amplifying Label

We report an ultrasensitive sandwich-type electrochemical immunosensor to detect the breast cancer biomarker CA 15-3. Amine-functionalized composite of reduced graphene oxide and Fe3O4 nanoparticles (MRGO-NH2) was used as an electrochemical sensing platform material to modify the electrodes. The nanocomposite comprising Pt and Fe3O4 nanoparticles (NPs) anchored on multiwalled carbon nanotubes (Pt-Fe3O4-MWCNTs-NH2) was utilized as a pseudoenzymatic signal-amplifying label. Compared to reduced graphene oxide, the composite MRGO-NH2 platform material demonstrated a higher electrochemical signal. In the Pt-Fe3O4-MWCNTs-NH2 label, multiwalled carbon nanotubes provided the substratum to anchor abundant catalytic Pt and Fe3O4 NPs. The nanocomposites were thoroughly characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. An electroanalytical study and prevalidation of the immunosensor was carried out. The immunosensor exhibited exceptional capabilities in detecting CA 15-3, offering a wider linear range of 0.0005-100 U mL-1 and a lower detection limit of 0.00008 U mL-1. Moreover, the designed immunosensor showed good specificity, reproducibility, and acceptable stability. The sensor was successfully applied to analyze samples from breast cancer patients, yielding reliable results.

Development of an inexpensive and rapidly preparable enzymatic pencil graphite biosensor for monitoring of glyphosate in waters

Glyphosate (GLY) is the most widely used non-selective broad-spectrum herbicide worldwide under well-reported side effects on the environment and human health. That's why it's necessary to control its presence in the environment. This work describes the development of an affordable, simple, and accurate electrochemical biosensor using a pencil graphite electrode as support, a horseradish peroxidase enzyme immobilized on a polysulfone membrane doped with multi-walled carbon nanotubes. The developed electrochemical sensor was used in the determination of GLY in river and drinking water samples. Cyclic voltammetry and amperometry were used as electrochemical detection techniques for the characterization and analytical application of the developed biosensor. The working mechanism of the biosensor is based on the inhibition of the peroxidase enzyme by GLY. Under optimal experimental conditions, the biosensor showed a linear response in the concentration range of 0.1 to 10 mg L^-1. The limits of detection and quantification are 0.025 ± 0.002 and 0.084 ± 0.007 mg L^-1, respectively, which covers the maximum residual limit established by the EPA for drinking water (0.7 mg L^-1). The proposed biosensor demonstrated high reproducibility, excellent analytical performance, repeatability, and accuracy. The sensor proved to be selective against other pesticides, organic acids, and inorganic salts. Application on real samples showed recovery rates ranging between 98.18 ± 0.11 % and 97.32 ± 0.23 %. The analytical features of the proposed biosensor make it an effective and useful tool for the detection of GLY for environmental analysis.

Potential Environmental and Health Implications from the Scaled-Up Production and Disposal of Nanomaterials Used in Biosensors

Biosensors often combine biological recognition elements with nanomaterials of varying compositions and dimensions to facilitate or enhance the operating mechanism of the device. While incorporating nanomaterials is beneficial to developing high-performance biosensors, at the stages of scale-up and disposal, it may lead to the unmanaged release of toxic nanomaterials. Here we attempt to foster connections between the domains of biosensors development and human and environmental toxicology to encourage a holistic approach to the development and scale-up of biosensors. We begin by exploring the toxicity of nanomaterials commonly used in biosensor design. From our analysis, we introduce five factors with a role in nanotoxicity that should be considered at the biosensor development stages to better manage toxicity. Finally, we contextualize the discussion by presenting the relevant stages and routes of exposure in the biosensor life cycle. Our review found little consensus on how the factors presented govern nanomaterial toxicity, especially in composite and alloyed nanomaterials. To bridge the current gap in understanding and mitigate the risks of uncontrolled nanomaterial release, we advocate for greater collaboration through a precautionary One Health approach to future development and a movement towards a circular approach to biosensor use and disposal.

A review on the recent achievements on coronaviruses recognition using electrochemical detection methods

Various coronaviruses, which cause a wide range of human and animal diseases, have emerged in the past 50 years. This may be due to their abilities to recombine, mutate, and infect multiple species and cell types. A novel coronavirus, which is a family of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), has been termed COVID-19 by the World Health Organization (WHO). COVID-19 is the strain that has not been previously identified in humans. The early identification and diagnosis of the virus is crucial for effective pandemic prevention. In this study, we review shortly various diagnostic methods for virus assay and focus on recent advances in electrochemical biosensors for COVID-19 detection.

Persimmon Tannin-Reduction Graphene Oxide-Platinum-Palladium Nanocomposite Decorated on Screen-Printed Carbon Electrode for Enhanced Electrocatalytic Reduction of Hydrogen Peroxide

According to studies, Hydrogen peroxide (H2O2) is a significant biomarker of physiological processes. Unnormal H2O2 levels in human body may result in diseases. Hence, there is an increasing demand for monitoring the H2O2 concentrations in biological specimen. Here, we construct a non-enzymatic H2O2 electrochemical biosensor based on persimmon tannin-reduced graphene oxide-platinum-palladium nanocomposite (PrG-Pt@Pd NPs) modified with screen-printed carbon electrode (SPE). Combined with suitable electrocatalytic mode for Pt@Pd NPs, high specific large specific volume and good electrical conductivity of RGO, well as the superior sorption capacity of PT for metal-based nano-ion, the PrGPt@Pd striped pleasing heterogeneous catalytic activity toward H2O2 reduction via the synergistic effect. In experimental conditions of optimal, this non-enzymatic electrochemical sensor exhibited excellent electrocatalytic performance for H2O2 with less negative potential (−0.5 V), fast response time (<3 s), it shows good linearity in the range of 5.0–100.0 μM, in addition to this LOD of this sensor was 0.059 μM as well as the excellent sensitivity of the sensor (13.696 μA·μM−1·cm−2). Due to excellent specificity, lower detection limit, and good recovery (98.70–99.96%) in the spiked measurements of human serum samples, this non-enzymatic electrochemical biosensor paves the way for H2O2 detection at ultra-low concentrations in physiology and diagnosis.

An electrochemical biosensing platform for progesterone hormone detection using magnetic graphene oxide

In recent times, graphene and its derivatives have turned out to be emerging nanomaterials as transducers to promote electron transport in the field of biosensing using electrochemical techniques. In electrochemical biosensing strategies, key factors such as signal amplification, stability, and sensitivity are necessary for attaining improved sensor performance. In the present work, we synthesized magnetic nanocomposites of graphene oxide and employed them as an electrode material for the loading of bio receptors. The increased surface area with high electric conductance enhanced the sensor's response. The immobilization of progesterone (PGN) antibodies on the modified electrode-sensing surface led to a hindered electron transport that decreased the current response. The developed electrochemical immunosensor assembled successfully in a stepwise process using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies along with the electrochemical impedance spectroscopy (EIS) analysis. The current response decreased linearly with the increased progesterone (PGN) concentration range of 0.01 pM-1000 nM with excellent detection limits of 0.15 pM (DPV) and 0.17 pM (CV) under optimal experimental conditions. The label-free electrochemical immunosensor has shown a promising platform for rapid and direct analysis of PGN due to its high sensitivity, selectivity, stability, and repeatability in water samples.

Multimodal/Multifunctional Nanomaterials in (Bio)electrochemistry: Now and in the Coming Decade

Multifunctional nanomaterials, defined as those able to achieve a combined effect or more than one function through their multiple functionalization or combination with other materials, are gaining increasing attention in the last years in many relevant fields, including cargo targeted delivery, tissue engineering, in vitro and/or in vivo diseases imaging and therapy, as well as in the development of electrochemical (bio)sensors and (bio)sensing strategies with improved performance. This review article aims to provide an updated overview of the important advances and future opportunities exhibited by electrochemical biosensing in connection to multifunctional nanomaterials. Accordingly, representative aspects of recent approaches involving metal, carbon, and silica-based multifunctional nanomaterials are selected and critically discussed, as they are the most widely used multifunctional nanomaterials imparting unique capabilities in (bio)electroanalysis. A brief overview of the main remaining challenges and future perspectives in the field is also provided.

Development of Chitosan Functionalized Magnetic Nanoparticles with Bioactive Compounds

In this study, magnetic maghemite nanoparticles, which belong to the group of metal oxides, were functionalized with chitosan, a non-toxic, hydrophilic, biocompatible, biodegradable biopolymer with anti-bacterial effects. This was done using different synthesis methods, and a comparison of the properties of the synthesized chitosan functionalized maghemite nanoparticles was conducted. Characterization was performed using scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Characterizations of size distribution were performed using dynamic light scattering (DLS) measurements and laser granulometry. A chitosan functionalization layer was confirmed using potentiometric titration on variously synthesized chitosan functionalized maghemite nanoparticles, which is important for further immobilization of bioactive compounds. Furthermore, after activation of chitosan functionalized maghemite nanoparticles with glutaraldehyde (GA) or pentaethylenehexamine (PEHA), immobilization studies of enzyme cholesterol oxidase (ChOx) and horseradish peroxidase (HRP) were conducted. Factors influencing the immobilization of enzymes, such as type and concentration of activating reagent, mass ratio between carrier and enzyme, immobilization time and enzyme concentration, were investigated. Briefly, microparticles made using the chitosan suspension cross-linking process (MC2) proved to be the most suitable for obtaining the highest activity of immobilized enzyme, and nanoparticles functionalized with chitosan using the covalent binding method (MC3) could compete with MC2 for their applications.

Recent Applications of Magnetic Nanoparticles in Food Analysis

Nanotechnology has become a topic of interest due to the outstanding advantages that the use of nanomaterials offers in many fields. Among them, magnetic nanoparticles (m-NPs) have been one of the most widely applied in recent years. In addition to the unique features of nanomaterials in general, which exclusively appear at nanoscale, these present magnetic or paramagnetic properties that result of great interest in many applications. In particular, in the area of food analysis, the use of these nanomaterials has undergone a considerable increase since they can be easily separated from the matrix in sorbent-based extractions, providing a considerable simplification of the procedures. This allows reducing cost and giving fast responses, which is essential in the food trade to guarantee consumer safety. These materials can also be easily tunable, providing higher selectivity. Moreover, their particular electrical, thermal and optical characteristics allow enhancing sensor signals, increasing the sensitivity of the approaches based on this type of device. The aim of this review article is to summarise the most remarkable applications of m-NPs in food analysis in the last five years (2016–2020) showing a general view of the use of such materials in the field.

Applications of Graphene and Its Derivatives in the Upstream Oil and Gas Industry: A Systematic Review

Graphene and its derivatives, with their unique two-dimensional structures and excellent physical and chemical properties, have been an international research hotspot both in the research community and industry. However, in application-oriented research in the oil and gas industry they have only drawn attention in the past several years. Their excellent optical, electrical, thermal and mechanical performance make them great candidates for use in oil and gas exploration, drilling, production, and transportation. Combined with the actual requirements for well working fluids, chemical enhanced oil recovery, heavy oil recovery, profile control and water shutoff, tracers, oily wastewater treatment, pipeline corrosion prevention treatment, and tools and apparatus, etc., this paper introduces the behavior in water and toxicity to organisms of graphene and its derivatives in detail, and comprehensively reviews the research progress of graphene materials in the upstream oil and gas industry. Based on this, suggestions were put forward for the future research. This work is useful to the in-depth mechanism research and application scope broadening research in the upstream oil and gas industry.

Design of heterostructured hybrids comprising ultrathin 2D bismuth tungstate nanosheets reinforced by chloramphenicol imprinted polymers used as biomimetic interfaces for mass-sensitive detection

Combining nanomaterials in varying morphology and functionalities gives rise to a new class of composite materials leading to innovative applications. In this study, we designed a heterostructured hybrid material consisting of two-dimensional bismuth nanosheets augmented by molecularly imprinted networks. Antibiotic overuse is now one of the main concerns in health management, and their monitoring is highly desirable but challenging. So, for this purpose, the resulting composite interface was used as a transducer for quartz crystal microbalances. The main objective was to develop highly selective mass-sensitive sensor for chloramphenicol. Morphological investigation revealed the presence of ultrathin, square shaped nanosheets, 2-3 nm in height and further supplemented by imprinted polymers. Sensor responses are described as the decrease in the frequency of microbalances owing to chloramphenicol re-binding in the templated cavities, yielding a detection limit down to 0.74 μM. This sensor demonstrated a 100 % specific detection of chloramphenicol over its interfering and structural analogs (clindamycin, thiamphenicol, and florfenicol). This composite interface offers the advantage of selective binding and excellent sensitivity due to special heterostructured morphology, in addition to benefits of robustness and online monitoring. The results suggest that such composite-based sensors can be favorable platforms, especially for commercial prospects, to obtain selective detection of other biomolecules of clinical importance.

Functional Magnetic Graphene Composites for Biosensing

Magnetic graphene composites (MGCs), which are composed of magnetic nanoparticles with graphene or its derivatives, played an important role in sensors development. Due to the enhanced electronic properties and the synergistic effect of magnetic nanomaterials and graphene, MGCs could be used to realize more efficient sensors such as chemical, biological, and electronic sensors, compared to their single component alone. In this review, we first reviewed the various routes for MGCs preparation. Then, sensors based on MGCs were discussed in different groups, including optical sensors, electrochemical sensors, and others. At the end of the paper, the challenges and opportunities for MGCs in sensors implementation are also discussed.

Electrochemical virus detections with nanobiosensors

Infectious diseases are caused from pathogens, which need a reliable and fast diagnosis. Today, expert personnel and centralized laboratories are needed to afford much time in diagnosing diseases caused from pathogens.

Recent progress in electrochemical studies shows that biosensors are very simple, accurate, precise, and cheap at virus detection, for which researchers find great interest in this field. The clinical levels of these pathogens can be easily analyzed with proposed biosensors. Their working principle is based on affinity between antibody and antigen in body fluids. The progress still continues on these biosensors for accurate, rapid, reliable sensors in future.

Study of horseradish peroxidase and hydrogen peroxide bi-analyte sensor with boronate affinity-based molecularly imprinted film

A novel electrochemical horseradish peroxidase (HRP) sensor was developed based on boronate affinity-based electropolymerized polythionine (PTh) molecularly imprinted polymer (MIP) as specific recognition element for HRP on gold nanoparticles (AuNPs) modified glassy carbon electrode, in which PTh acted as the electrochemical probe for the sensor. The sensor was characterized by scanning electron microscopy and electron dispersive spectroscopy. Electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry were exploited for the study of the properties of the MIP sensor. The MIP sensor exhibited excellent linear response over the range of 2.0 × 10−10 mg/mL ∼ 1.0 × 10−7 mg/mL for HRP. In addition, with MIP film as HRP immobilized matrices, the sensor for the detection of H2O2 was developed with the MIP sensor based on the reduction of H2O2 catalyzed by HRP in the presence of electron mediator PTh. The sensor showed linear relationships between the current response and H2O2 concentration from 6.0 × 10−7 to 2.0 × 10−5 mol/L. HRP and H2O2 bi-analyte sensor based on MIP film was successfully developed in this work. The developed method can also be applicable for enzyme and its enzymatic substrate bi-analyte sensor.

Magnetic Particle Bioconjugates: A Versatile Sensor Approach

: Nanomaterial biosensors have revolutionized the entire scientific, technology, biomedical, materials science, and engineering fields. Among all nanomaterials, magnetic nanoparticles, microparticles, and beads are unique in offering facile conjugation of biorecognition probes for selective capturing of any desired analytes from complex real sample matrices (e.g., biofluids such as whole blood, serum, urine and saliva, tissues, food, and environmental samples). In addition, rapid separation of the particle-captured analytes by the simple use of a magnet for subsequent detection on a sensor unit makes the magnetic particle sensor approach very attractive. The easy magnetic isolation feature of target analytes is not possible with other inorganic particles, both metallic (e.g., gold) and non-metallic (e.g., silica), which require difficult centrifugation and separation steps. Magnetic particle biosensors have thus enabled ultra-low detection with ultra-high sensitivity that has traditionally been achieved only by radioactive assays and other tedious optical sources. Moreover, when traditional approaches failed to selectively detect low-concentration analytes in complex matrices (e.g., colorimetric, electrochemistry, and optical methods), magnetic particle-incorporated sensing strategies enabled sample concentration into a defined microvolume of large surface area particles for a straightforward detection. The objective of this article is to highlight the ever-growing applications of magnetic materials for the detection of analytes present in various real sample matrices. The central idea of this paper was to show the versatility and advantages of using magnetic particles for a variety of sample matrices and analyte types and the adaptability of different transducers with the magnetic particle approaches.

Functionalization of Carbon Nanomaterials for Biomedical Applications

Over the past decade, carbon nanostructures (CNSs) have been widely used in a variety of biomedical applications. Examples are the use of CNSs for drug and protein delivery or in tools to locally dispense nucleic acids to fight tumor affections. CNSs were successfully utilized in diagnostics and in noninvasive and highly sensitive imaging devices thanks to their optical properties in the near infrared region. However, biomedical applications require a complete biocompatibility to avoid adverse reactions of the immune system and CNSs potentials for biodegradability. Water is one of the main constituents of the living matter. Unfortunately, one of the disadvantages of CNSs is their poor solubility. Surface functionalization of CNSs is commonly utilized as an efficient solution to both tune the surface wettability of CNSs and impart biocompatible properties. Grafting functional groups onto the CNSs surface consists in bonding the desired chemical species on the carbon nanoparticles via wet or dry processes leading to the formation of a stable interaction. This latter may be of different nature as the van Der Waals, the electrostatic or the covalent, the π-π interaction, the hydrogen bond etc. depending on the process and on the functional molecule at play. Grafting is utilized for multiple purposes including bonding mimetic agents such as polyethylene glycol, drug/protein adsorption, attaching nanostructures to increase the CNSs opacity to selected wavelengths or provide magnetic properties. This makes the CNSs a very versatile tool for a broad selection of applications as medicinal biochips, new high-performance platforms for magnetic resonance (MR), photothermal therapy, molecular imaging, tissue engineering, and neuroscience. The scope of this work is to highlight up-to-date using of the functionalized carbon materials such as graphene, carbon fibers, carbon nanotubes, fullerene and nanodiamonds in biomedical applications.

Acetylcholinesterase Biosensor Based On Mesoporous Hollow Carbon Spheres/Core-Shell Magnetic Nanoparticles-Modified Electrode for the Detection of Organophosphorus Pesticides

The present study investigated the synthesis of mesoporous hollow carbon spheres (MHCS) and magnetic mesoporous hollow carbon spheres with core-shell structures (Fe₃O₄@MHCS). Two acetylcholinesterase sensors (acetylcholinesterase/mesoporous hollow carbon spheres/glassy carbon electrode (AChE/MHCS/GCE) and acetylcholinesterase/core-shell magnetic mesoporous hollow carbon spheres/glassy carbon electrode (AChE/Fe₃O₄@MHCS/GCE) based on mesoporous carbon materials were prepared. Under the optimum conditions, using Malathion as the model compound, the developed biosensors showed a wide detection range, low detection limit, good reproducibility, and high stability. The AChE/MHCS/GCE electrochemical sensor response exhibited two good linear ranges at the incubation time of 10 min at the Malathion concentration ranges of 0.01 to 100 ppb and 100 to 600 ppb, with a detection limit of 0.0148 ppb (S/N = 3). The AChE/Fe₃O₄@MHCS/GCE electrochemical sensor that was operated with an incubation time of 12 min at the malathion concentration ranges between 0.01–50 ppb and 50–600 ppb had a detection limit of 0.0182 ppb (S/N = 3). Moreover, the AChE/MHCS/GCE and AChE/Fe₃O₄@MHCS/GCE biosensors were effective for the detection of real samples, and were demonstrated to be suitable for the field-testing of organophosphorus pesticide (OP) residues.

Electrochemical biosensor based on Se-doped MWCNTs-graphene and Y-shaped DNA-aided target-triggered amplification strategy

A highly sensitive electrochemical biosensor for detection of platelet-derived growth factor-BB (PDGF-BB) is developed by using Se-doped multi-walled carbon nanotubes (MWCNTs)-graphene hybrids as electrode supporting substrate, hemin/G-quadruplex as trace labels and Y-shaped DNA-aided target recycling as signal magnifier. The aptamer-containing hairpin probes were first immobilized on the electrode. When target PDGF-BB was added, the aptamer binded PDGF-BB to trigger catalytic assembly of two other hairpins to form many G-quadruplex Y-junction DNA structures, which released PDGF-BB to again bind the intact aptamer to initiate another assembly cycle. G-quadruplex/hemin complexes were produced when hemin was added to generate substantially amplified current output. The developed assay showed a linear range toward PDGF-BB from 0.1 pM to 10 nM with a detection limit of 27 fM (S/N = 3). The method showed excellent specificity and repeatability, and could be expediently applied for sensitive detection of other molecules by simply changing the aptamers.