Electrochemical immunosensor for interferon-γ based on disposable ITO detector and HRP-antibody-conjugated nano gold as signal tag

The level pro-inflammatory and anti-inflammatory biomarkers in patients with chronic mechanical low back pain under pulse radiofrequency therapy

Low back pain is a frequent and recurrent condition, often with a non-specific cause. Conventional treatment methods are generally insufficient in the treatment of chronic low back pain. The aim of the study was to estimate the level of IFN, IL-1, IL-6 (proinflammatory), IL-10, IL-4 (anti-inflammatory) and VEGF proteins in the serum of patients with chronic mechanical low back pain under Pulse radiofrequency (PRF) therapy. The study was carried out on 40 patients 20-60 years old, diagnosed with chronic low back pain for at least 4 months, primary complaint on lumbosacral low back pain, pain intensity VAS (visual analog scale) score of 5 and above, not responding well to conservative treatment (analgesic drugs, physiotherapy, etc.). Therapeutic Radiofrequency applications were carried out with an RF generator (RFG 3C Plus, Radionics). Blood samples were taken 1 day before interventional treatment (control), then 1 day (group1) and 15 days (group 2) after. The serum level of IFN, IL-1, IL-6, IL-10, IL-4 and VEGF l was analyzed with ELISA test. It was shown that as a result of PRF treatment the level of IL-1 was decreased while the levels of IL-4 and IL-6 were increased. It was concluded that the increase in serum levels of proinflammatory cytokines may be correlated with the severity of pain and that the increase in the level of anti-inflammatory cytokines reduces pain by reducing inflammation. Keywords: chronic low back pain, cytokines, radiofrequency therapy

Interferon-γ detection in point of care diagnostics: Short review

Interferon (IFN)-γ is a cytokine secreted by immune cells. The elevated levels of IFN-γ are an early indicator of multiple diseases such as tuberculosis and autoimmune diseases. This short review focuses on different sensing methods based on optical, electrochemical, and mechanical principles. We explain how specific biorecognition molecules such as antibodies and aptamers are employed in the sensing methods. We also compare different surface functionalization methods and their details. Although the review gives an overview of only IFN-γ sensing, the same strategies can be applied to sensing other analytes with appropriate modifications.

Recent advances in the detection of interferon-gamma as a TB biomarker

Tuberculosis (TB) is one of the main infectious diseases worldwide and accounts for many deaths. It is caused by Mycobacterium tuberculosis usually affecting the lungs of patients. Early diagnosis and treatment are essential to control the TB epidemic. Interferon-gamma (IFN-γ) is a cytokine that plays a part in the body’s immune response when fighting infection. Current conventional antibody-based TB sensing techniques which are commonly used include enzyme-linked immunosorbent assay (ELISA) and interferon-gamma release assays (IGRAs). However, these methods have major drawbacks, such as being time-consuming, low sensitivity, and inability to distinguish between the different stages of the TB disease. Several electrochemical biosensor systems have been reported for the detection of interferon-gamma with high sensitivity and selectivity. Microfluidic techniques coupled with multiplex analysis in regular format and as lab-on-chip platforms have also been reported for the detection of IFN-γ. This article is a review of the techniques for detection of interferon-gamma as a TB disease biomarker. The objective is to provide a concise assessment of the available IFN-γ detection techniques (including conventional assays, biosensors, microfluidics, and multiplex analysis) and their ability to distinguish the different stages of the TB disease.

Tumor-Induced Inflammatory Cytokines and the Emerging Diagnostic Devices for Cancer Detection and Prognosis

Chronic inflammation generated by the tumor microenvironment is known to drive cancer initiation, proliferation, progression, metastasis, and therapeutic resistance. The tumor microenvironment promotes the secretion of diverse cytokines, in different types and stages of cancers. These cytokines may inhibit tumor development but alternatively may contribute to chronic inflammation that supports tumor growth in both autocrine and paracrine manners and have been linked to poor cancer outcomes. Such distinct sets of cytokines from the tumor microenvironment can be detected in the circulation and are thus potentially useful as biomarkers to detect cancers, predict disease outcomes and manage therapeutic choices. Indeed, analyses of circulating cytokines in combination with cancer-specific biomarkers have been proposed to simplify and improve cancer detection and prognosis, especially from minimally-invasive liquid biopsies, such as blood. Additionally, the cytokine signaling signatures of the peripheral immune cells, even from patients with localized tumors, are recently found altered in cancer, and may also prove applicable as cancer biomarkers. Here we review cytokines induced by the tumor microenvironment, their roles in various stages of cancer development, and their potential use in diagnostics and prognostics. We further discuss the established and emerging diagnostic approaches that can be used to detect cancers from liquid biopsies, and additionally the technological advancement required for their use in clinical settings.

Electrochemical Biosensors for Cytokine Profiling: Recent Advancements and Possibilities in the Near Future

Cytokines are soluble proteins secreted by immune cells that act as molecular messengers relaying instructions and mediating various functions performed by the cellular counterparts of the immune system, by means of a synchronized cascade of signaling pathways. Aberrant expression of cytokines can be indicative of anomalous behavior of the immunoregulatory system, as seen in various illnesses and conditions, such as cancer, autoimmunity, neurodegeneration and other physiological disorders. Cancer and autoimmune diseases are particularly adept at developing mechanisms to escape and modulate the immune system checkpoints, reflected by an altered cytokine profile. Cytokine profiling can provide valuable information for diagnosing such diseases and monitoring their progression, as well as assessing the efficacy of immunotherapeutic regiments. Toward this goal, there has been immense interest in the development of ultrasensitive quantitative detection techniques for cytokines, which involves technologies from various scientific disciplines, such as immunology, electrochemistry, photometry, nanotechnology and electronics. This review focusses on one aspect of this collective effort: electrochemical biosensors. Among the various types of biosensors available, electrochemical biosensors are one of the most reliable, user-friendly, easy to manufacture, cost-effective and versatile technologies that can yield results within a short period of time, making it extremely promising for routine clinical testing.

Portable electrochemical immunosensor for detection of Mycobacterium tuberculosis secreted protein CFP10-ESAT6 in clinical sputum samples

An early detection of Mycobacterium tuberculosis is very important to reduce the number of fatal cases and allow for fast recovery. However, the interpretation of the result from smear microscopy requires skilled personnel due to the propensity of the method to produce false-negative results. In this work, a portable, rapid, and simple sandwich-type immunosensor reader has been developed that is able to detect the presence of M. tuberculosis in sputum samples. By using sandwich-type immunosensor, an anti-CFP10-ESAT6 antibody was immobilized onto the graphene/polyaniline (GP/PANI)-modified gold screen-printed electrode. After incubation with the target CFP10-ESAT6 antigen, the iron/gold magnetic nanoparticles (Fe₃O₄/Au MNPs) conjugated with anti-CFP10-ESAT6 antibody were used to complete the sandwich format. Differential pulse voltammetry (DPV) technique was used to detect the CFP10-ESAT6 antigen at the potential range of 0.0-1.0 V. The detection time is less than 2 h. Under optimal condition, CFP10-ESAT6 antigen was detected in a linear range from 10 to 500 ng mL^-1 with a limit of detection at 1.5 ng mL^-1. The method developed from this process was then integrated into a portable reader. The performance of the sensor was investigated and compared with the standard methods (culture and smear microscopy). It provides a good correlation (100% sensitivity and 91.7% specificity) with both methods of detection for M. tuberculosis in sputum samples henceforth, demonstrating the potential of the device as a more practical screening tool.Graphical abstract.

Nanobioconjugates for Signal Amplification in Electrochemical Biosensing

Nanobioconjugates are hybrid materials that result from the coalescence of biomolecules and nanomaterials. They have emerged as a strategy to amplify the signal response in the biosensor field with the potential to enhance the sensitivity and detection limits of analytical assays. This critical review collects a myriad of strategies for the development of nanobioconjugates based on the conjugation of proteins, antibodies, carbohydrates, and DNA/RNA with noble metals, quantum dots, carbon- and magnetic-based nanomaterials, polymers, and complexes. It first discusses nanobioconjugates assembly and characterization to focus on the strategies to amplify a biorecognition event in biosensing, including molecular-, enzymatic-, and electroactive complex-based approaches. It provides some examples, current challenges, and future perspectives of nanobioconjugates for the amplification of signals in electrochemical biosensing.

Electrochemical immunosensor for the determination of the cytokine interferon gamma (IFN-γ) in saliva

A simple, fast and sensitive amperometric immunosensing method for the determination of the clinically relevant cytokine interferon gamma (IFN-γ) in saliva complying the requirements demanded for this kind of sample is reported. The target analyte was sandwiched between a specific capture antibody covalently immobilized on a screen-printed electrode functionalized by the diazonium salt grafting of p-aminobenzoic acid, and a biotinylated detector antibody labeled with a streptavidin-horseradish peroxidase conjugate. The amperometric responses measured at - 0.20 V vs Ag pseudo-reference electrode upon addition of hydrogen peroxide in the presence of hydroquinone as the redox mediator allowed a calibration plot with a linear range between 2.5 and 2000 pg mL^-1 and a low limit of detection (1.6 pg mL^-1) to be obtained. In addition, a good selectivity against other non-target proteins was achieved. The developed method was validated by analyzing a WHO 1st International Standard for IFN-γ. In addition, the immunosensor was used for the determination of the endogenous IFN-γ in saliva with results in excellent agreement with those obtained by a commercial ELISA kit.

An amplified label-free electrochemical aptasensor of γ-interferon based on target-induced DNA strand transform of hairpin-to-linear conformation enabling simultaneous capture of redox probe and target

In this work, a novel and signal-amplified label-free electrochemical aptasensor was developed and enabled efficient determination of γ-interferon (IFN-γ), based on target-induced DNA strand transform of hairpin-to-linear conformation combining with simultaneous capture of redox probe and target. Gold nanoparticles (AuNPs) were electrodeposited in the matrix of poly(amidoamine) dendrimer (PAMAM), followed by drop-casting addition on MoS₂ nanosheets to prepare AuNPs- PAMAM/MoS₂ composites. HS-terminated hairpin-DNA aptamer of IFN-γ was conjugated with AuNPs to prepare aptamer-AuNPs-PAMAM/MoS₂ onto glassy carbon electrode (GCE), by using bovine serum albumin as the cross-linker and stabilizer. Methylene blue (MB) as a redox probe was absorbed on IFN-γ aptamer. In the presence of IFN-γ, MB electrochemical signal increased gradually. The preparation processes, mechanisms and optimal experiment conditions of aptamer- AuNPs-PAMAM/MoS₂/MB/GCE sensing platform were studied by electron microscope imaging technologies, spectral curves and electrochemical measurements. There is a well plotting linear relationship between the peak current intensities of MB and IFN-γ contents in the range of 0.01-1000 pg mL^-1, showing a low detection limit of 2 fg mL^-1. Experimental results testified that the aptasensor had highly sensitive and selective responses toward IFN-γ, over potential interferents. In real biological samples, the aptasensor of IFN-γ had superior detection recoveries, indicating its high detection performance and feasibility for practicability.

A label-free IFN-γ aptasensor based on target-triggered allosteric switching of aptamer beacon and streptavidin-inorganic hybrid composites

A label-free electrochemical aptasensor was developed for the sensitive detection of interferon-gamma (IFN-γ). To do this, a diblock dual-aptamer allosteric hairpin (DDAH) was designed, followed by conjugation with gold nanoparticles (DDAH&AuNP). The presence of target destroyed the stable hairpin structure, and then the catalytic cleavage of DNAzymes removed the IFN-γ-binding molecules, triggering the allosteric switching from inactive hairpin to active streptavidin aptamer (A-DDAH&AuNP) in homogeneous system. Moreover, streptavidin-inorganic hybrid nanoflowers decorated with graphene composites (SFG) were synthesized and used as substrates to modify glassy carbon electrodes (SFG/GCE). SFG specifically bind to the A-DDAH&AuNP to realize high-efficient readout of signals. Under the optimal conditions and by using differential pulse stripping voltammetry (DPSV), the response peak currents increases linearly with the logarithm of the IFN-γ concentration in the range between 0.1 pg mL^-1 and 500 ng/mL. The detection limit is as low as 19 fg mL^-1. The aptasensor also has excellent electrochemical performances, which exhibits broad application prospects in biometric analysis.

Inorganic Complexes and Metal-Based Nanomaterials for Infectious Disease Diagnostics

Infectious diseases claim millions of lives each year. Robust and accurate diagnostics are essential tools for identifying those who are at risk and in need of treatment in low-resource settings. Inorganic complexes and metal-based nanomaterials continue to drive the development of diagnostic platforms and strategies that enable infectious disease detection in low-resource settings. In this review, we highlight works from the past 20 years in which inorganic chemistry and nanotechnology were implemented in each of the core components that make up a diagnostic test. First, we present how inorganic biomarkers and their properties are leveraged for infectious disease detection. In the following section, we detail metal-based technologies that have been employed for sample preparation and biomarker isolation from sample matrices. We then describe how inorganic- and nanomaterial-based probes have been utilized in point-of-care diagnostics for signal generation. The following section discusses instrumentation for signal readout in resource-limited settings. Next, we highlight the detection of nucleic acids at the point of care as an emerging application of inorganic chemistry. Lastly, we consider the challenges that remain for translation of the aforementioned diagnostic platforms to low-resource settings.

A Novel Microfluidic Point-of-Care Biosensor System on Printed Circuit Board for Cytokine Detection

Point of Care (PoC) diagnostics have been the subject of considerable research over the last few decades driven by the pressure to detect diseases quickly and effectively and reduce healthcare costs. Herein, we demonstrate a novel, fully integrated, microfluidic amperometric enzyme-linked immunosorbent assay (ELISA) prototype using a commercial interferon gamma release assay (IGRA) as a model antibody binding system. Microfluidic assay chemistry was engineered to take place on Au-plated electrodes within an assay cell on a printed circuit board (PCB)-based biosensor system. The assay cell is linked to an electrochemical reporter cell comprising microfluidic architecture, Au working and counter electrodes and a Ag/AgCl reference electrode, all manufactured exclusively via standard commercial PCB fabrication processes. Assay chemistry has been optimised for microfluidic diffusion kinetics to function under continual flow. We characterised the electrode integrity of the developed platforms with reference to biological sampling and buffer composition and subsequently we demonstrated concentration-dependent measurements of H₂O₂ depletion as resolved by existing FDA-validated ELISA kits. Finally, we validated the assay technology in both buffer and serum and demonstrate limits of detection comparable to high-end commercial systems with the addition of full microfluidic assay architecture capable of returning diagnostic analyses in approximately eight minutes.

Emerging Biosensing Technologies for Neuroinflammatory and Neurodegenerative Disease Diagnostics

Neuroinflammation plays a critical role in the onset and progression of many neurological disorders, including Multiple Sclerosis, Alzheimer's and Parkinson's diseases. In these clinical conditions the underlying neuroinflammatory processes are significantly heterogeneous. Nevertheless, a common link is the chronic activation of innate immune responses and imbalanced secretion of pro and anti-inflammatory mediators. In light of this, the discovery of robust biomarkers is crucial for screening, early diagnosis, and monitoring of neurological diseases. However, the difficulty to investigate biochemical processes directly in the central nervous system (CNS) is challenging. In recent years, biomarkers of CNS inflammatory responses have been identified in different body fluids, such as blood, cerebrospinal fluid, and tears. In addition, progress in micro and nanotechnology has enabled the development of biosensing platforms capable of detecting in real-time, multiple biomarkers in clinically relevant samples. Biosensing technologies are approaching maturity where they will become deployed in community settings, at which point screening programs and personalized medicine will become a reality. In this multidisciplinary review, our goal is to highlight both clinical and recent technological advances toward the development of multiplex-based solutions for effective neuroinflammatory and neurodegenerative disease diagnostics and monitoring.

Potential-Resolved Electrochemiluminescence for Simultaneous Determination of Triple Latent Tuberculosis Infection Markers

A novel electrochemiluminescence (ECL) immunosensor based on the potential-resolved strategy was first developed for simultaneous determination of triple latent tuberculosis infection (LTBI) markers with high sensitivity, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and interleukin (IL)-2. In this work, luminol and self-prepared carbon quantum dots and CdS quantum dots were integrated onto gold nanoparticles and magnetic beads in sequence to fabricate potential-resolved ECL nanoprobes with signal amplification. IFN-γ-antibody (Ab)1, TNF-α-Ab1, and IL-2-Ab1 were separately immobilized on three spatially resolved areas of a patterned indium tin oxide electrode to capture the corresponding LTBI markers, which were further recognized by IFN-γ-Ab2, TNF-α-Ab2, and IL-2-Ab2-functionalized ECL nanoprobes. The binding reaction of antibody-functionalized ECL nanoprobes and the captured LTBI markers will generate three sensitive and potential-resolved ECL signals during one potential scanning, and the ECL intensities reflect the concentrations of IFN-γ, TNF-α, and IL-2 in the range of 1.6-200 pg mL^-1. Therefore, the multiplexed ECL immunosensor provided an effective approach for simultaneous detection of triple LTBI markers in human serum, so it will be beneficial to facilitate more accurate and reliable clinical diagnosis for LTBI.

A novel electrochemical immunosensor based on ITO modified by carboxyl-ended silane agent for ultrasensitive detection of MAGE-1 in human serum

A new, low-cost electrochemical immunosensor was developed for rapid detection of Melanoma-associated antigen 1 (MAGE-1), a cancer biomarker. The fabrication procedure of immunosensor was based on the covalent immobilization of anti-MAGE-1, biorecognition molecule, on ITO electrode by carboxyethylsilanetriol (CTES) monolayer. The biosensing MAGE-1 antigen was monitored by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) technique. Apart from these techniques, single frequency impedance (SFI) was used for investigation of antibody-antigen interactions. Scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) were utilized for characterization of the proposed biosensor. To fabricate highly sensitive, good stability immunosensor, some parameters were optimized. Under optimal conditions, the developed electrochemical immunosensor for MAGE-1 exhibited a dynamic range of 4 fg/mL and 200 fg/mL with a low detection limit of 1.30 fg/mL. It had acceptable repeatability (5.05%, n = 20) and good storage stability (3.58% loss after 10 weeks). Moreover, this electrochemical immunosensor has been successfully applied to the determination of MAGE-1 in human serum samples.

Novel Electrochemiluminescence-Sensing Platform for the Precise Analysis of Multiple Latent Tuberculosis Infection Markers

Latent tuberculosis infection (LTBI) is one of the major contributing factors for the high incidence of tuberculosis, and the low contents of LTBI markers in human serum present a great challenge for the diagnosis of LTBI. Here, we reported a novel electrochemiluminescence (ECL)-sensing platform for the precise analysis of multiple LTBI markers, interferon-gamma (IFN-γ) and interleukin (IL)-2. In this approach, self-prepared carbon quantum dots (CQDs) and luminol were integrated onto gold nanoparticles (AuNPs), which were further enriched on the surface of magnetic bead (MB) to create two solid-phase ECL nanoprobes (MB@Au@CQDs and MB@Au@luminol) for improving the detection sensitivity efficiently. Graphene oxide (GO) and AuNPs were electrodeposited onto a patterned indium tin oxide (ITO) electrode with two spatially resolved areas in sequence to form two sensitive and stable sensing areas. IFN-γ-antibody (Ab)₁ and IL-2-Ab₁ were separately immobilized on the two sensing areas to capture the corresponding LTBI markers, which were further recognized by IFN-γ-Ab₂ and IL-2-Ab₂ labeled as MB@Au@CQDs and MB@Au@luminol. The ECL intensity depended linearly on the content of IFN-γ and IL-2 in the range of 0.01-1000 pg mL^-1, with a low detection limit of 10 fg mL^-1. The proposed ECL-sensing platform is simple, sensitive, accurate, reliable, and specific to the detection of rare IFN-γ and IL-2 in human serum and provides a valuable protocol for facilitating fast and precise diagnosis of LTBI.

Nanodiagnostics for tuberculosis detection

INTRODUCTION

Tuberculosis (TB) is a leading killer worldwide. End TB strategy aims at ending the TB epidemic by 2030. Early, accurate, and affordable diagnosis represents a cornerstone to achieve this goal. Innovative strategies for TB diagnostics have been introduced. However, the ideal assay is yet unavailable and conventional methods remain necessary for diagnosis. Unique properties of nanoparticles (NPs) have allowed their utilization in TB detection via targeting disease biomarkers. Area covered: Until now, around thirty-five TB NP-based assays have been partially or fully characterized. Accuracy, low-cost, and short time-to-result represent the common properties of proposed platforms. TB nanodiagnostics now encompass almost all clinical aspects of the disease including active TB, non-tuberculous mycobacteria, rifampicin resistant TB, TB/HIV co-infection, latent TB, and extra-pulmonary TB. This review summarizes state-of-the-art knowledge of TB nanodiagnostics for the last 10 years. Special consideration is given for fabrication concepts, detection strategies, and clinical performance using various clinical specimens. The potential of TB nanodiagnostics to fulfill the need for ideal MTB testing is assessed. Expert commentary: TB nanodiagnostics show promise to be ideal detection tools that can meet the rigorous demands to end the TB epidemic by 2030.

Recent Advances in Electrochemical Immunosensors

Immunosensors have experienced a very significant growth in recent years, driven by the need for fast, sensitive, portable and easy-to-use devices to detect biomarkers for clinical diagnosis or to monitor organic pollutants in natural or industrial environments. Advances in the field of signal amplification using enzymatic reactions, nanomaterials such as carbon nanotubes, graphene and graphene derivatives, metallic nanoparticles (gold, silver, various oxides or metal complexes), or magnetic beads show how it is possible to improve collection, binding or transduction performances and reach the requirements for realistic clinical diagnostic or environmental control. This review presents these most recent advances; it focuses first on classical electrode substrates, then moves to carbon-based nanostructured ones including carbon nanotubes, graphene and other carbon materials, metal or metal-oxide nanoparticles, magnetic nanoparticles, dendrimers and, to finish, explore the use of ionic liquids. Analytical performances are systematically covered and compared, depending on the detection principle, but also from a chronological perspective, from 2012 to 2016 and early 2017.

Emerging Cytokine Biosensors with Optical Detection Modalities and Nanomaterial-Enabled Signal Enhancement

Protein biomarkers, especially cytokines, play a pivotal role in the diagnosis and treatment of a wide spectrum of diseases. Therefore, a critical need for advanced cytokine sensors has been rapidly growing and will continue to expand to promote clinical testing, new biomarker development, and disease studies. In particular, sensors employing transduction principles of various optical modalities have emerged as the most common means of detection. In typical cytokine assays which are based on the binding affinities between the analytes of cytokines and their specific antibodies, optical schemes represent the most widely used mechanisms, with some serving as the gold standard against which all existing and new sensors are benchmarked. With recent advancements in nanoscience and nanotechnology, many of the recently emerging technologies for cytokine detection exploit various forms of nanomaterials for improved sensing capabilities. Nanomaterials have been demonstrated to exhibit exceptional optical properties unique to their reduced dimensionality. Novel sensing approaches based on the newly identified properties of nanomaterials have shown drastically improved performances in both the qualitative and quantitative analyses of cytokines. This article brings together the fundamentals in the literature that are central to different optical modalities developed for cytokine detection. Recent advancements in the applications of novel technologies are also discussed in terms of those that enable highly sensitive and multiplexed cytokine quantification spanning a wide dynamic range. For each highlighted optical technique, its current detection capabilities as well as associated challenges are discussed. Lastly, an outlook for nanomaterial-based cytokine sensors is provided from the perspective of optimizing the technologies for sensitivity and multiplexity as well as promoting widespread adaptations of the emerging optical techniques by lowering high thresholds currently present in the new approaches.

Amperometric IFN-γ immunosensors with commercially fabricated PCB sensing electrodes

Lab-on-a-Chip (LoC) technology has the potential to revolutionize medical Point-of-Care diagnostics. Currently, considerable research efforts are focused on innovative production technologies that will make commercial upscaling of lab-on-chip products financially viable. Printed circuit board (PCB) manufacturing techniques have several advantages in this field. In this paper we focus on transferring a complete IFN-γ enzyme-linked immune-sorbent assay (ELISA) onto a commercial PCB electrochemical biosensing platform, We adapted a commercially available ELISA to detect the enzyme product TMB/H2O2 using amperometry, successfully reproducing the colorimetry-obtained ELISA standard curve. The results demonstrate the potential for the integration of these components into an automated, disposable, electronic ELISA Lab-on-PCB diagnostic platform.