Bioreceptor modified electrochemical biosensors for the detection of life threating pathogenic bacteria: a review

The lack of reliable and efficient techniques for early monitoring to stop long-term effects on human health is an increasing problem as the pathogenesis effect of infectious bacteria is growing continuously. Therefore, developing an effective early detection technique coupled with efficient and continuous monitoring of pathogenic bacteria is increasingly becoming a global public health prime target. Electrochemical biosensors are among the strategies that can be utilized for accomplishing that goal with promising potential. In recent years, identifying target biological analytes by interacting with bioreceptors modified electrodes is among the most commonly used detection techniques in electrochemical biosensing strategies. The commonly employed bioreceptors are nucleic acid molecules (DNA or RNA), proteins, antibodies, enzymes, organisms, tissues, and biomimetic components such as molecularly imprinted polymers. Despite the advancement in electrochemical biosensing, developing a reliable and effective biosensor for detecting pathogenic bacteria is still in the infancy stage with so much room for growth. A major milestone in addressing some of the issues and improving the detection pathway is the investigation of specific bacterial detection techniques. The present study covers the fundamental concepts of electrochemical biosensors, human PB illnesses, and the latest electrochemical biosensors based on bioreceptor elements that are designed to detect specific pathogenic bacteria. This study aims to assist researchers with the most up-to-date research work in the field of bio-electrochemical pathogenic bacteria detection and monitoring.

Recent advances in gold nanoparticles-based biosensors for tuberculosis determination

Tuberculosis (TB) is one of the major killer diseases affecting lung parenchymal tissues. Mycobacterium tuberculosis (Mtb) is the bacterium that causes it. It most commonly affects the lungs, although it can affect any part of the body, including the stomach, glands, bones, and nervous system. Although anti-mycobacterial drugs are available, it remains a major threat to public health due to the rise of drug-resistant strains, and early and accurate diagnosis is very important. Currently, research science and medical communities are focusing on the use of cost-effective biosensors to manage human biological processes and assess accurate health diagnostics. Due to their high sensitivity in chemical and biological assays, nanomaterials have been considered in the field of biosensors for better diagnosis, and among them, gold nanoparticles (AuNPs) can play an important role in accelerating the diagnosis of TB. Superior biocompatibility, conductivity, catalytic properties, high surface-to-volume ratio, and high density enable their widespread use in the fabrication of biosensors. This review evaluates the diagnostic accuracy of AuNP-based biosensors for the detection of Mtb. According to different transducers of biosensors, their structure, performance, advantages and limitations are summarized and compared. Moreover, the upcoming challenges in their analytical performance have been highlighted and the strategies to overcome those challenges have been briefly discussed.

Electrochemical detection of Oxaliplatin induced DNA damage in G-quadruplex structures

Oxaliplatin (OXP) is a platinum-based chemotherapeutic agent that induces DNA damage by forming intra- and interstrand crosslinks, mainly at the N7 sites of adenine (A) and guanine (G) bases. In addition to double-stranded DNA, G-rich G-quadruplex (G4)-forming sequences can also be targeted by OXP. However, high doses of OXP can lead to drug resistance and cause serious adverse effects during treatment. To better understand the targeting of G4 structures by OXP, their interactions as well as the molecular mechanisms underlying OXP resistance and adverse effects, there is a need for a rapid, quantitative, and cost-effective method to detect OXP and the damage it causes. In this study, we successfully fabricated a graphite electrode biosensor modified with gold nanoparticles (AuNPs) to investigate the interactions between OXP and the G4-forming promoter region (Pu22) of Vascular endothelial growth factor (VEGF). The overexpression of VEGF is known to be associated with tumor progression and the stabilization of VEGF G4 by small molecules is shown to suppresses VEGF transcription in different cancer cell lines. Differential pulse voltammetry (DPV) was used to investigate the interactions between OXP and Pu22-G4 DNA by monitoring the decrease in the oxidation signal of guanine with increasing OXP concentration. Under the optimized conditions (37 °C, 1:2 v/v AuNPs/water as electrode surface modifier, and 90 min incubation time) the developed probe showed a linear dynamic range of 1.0-10.0 μM with a detection limit of 0.88 μM and limit of quantification of 2.92 μM. Fluorescence spectroscopy was also used to support the electrochemical studies. We observed a decrease in the fluorescence emission of Thioflavin T in the presence of Pu22 upon addition of OXP. To our knowledge, this is the first electrochemical sensor developed to study OXP-induced damage to G4 DNA structures. Our findings provide new insights into the interactions between VEGF G4 and OXP, which could aid in targeting VEGF G4 structures and the development of new strategies to overcome OXP resistance.

Reduced Graphene Oxide-Polydopamine-Gold Nanoparticles: A Ternary Nanocomposite-Based Electrochemical Genosensor for Rapid and Early Mycobacterium tuberculosis Detection

Tuberculosis (TB) has been a devastating human illness for thousands of years. According to the WHO, around 10.4 million new cases of tuberculosis are identified every year, with 1.8 million deaths. To reduce these statistics and the mortality rate, an early and accurate TB diagnosis is essential. This study offers a highly sensitive and selective electrochemical biosensor for Mycobacterium tuberculosis (MTB) detection based on a ternary nanocomposite of reduced graphene oxide, polydopamine, and gold nanoparticles (rGO-PDA-AuNP). Avidin-biotin coupling was used to bind the MTB probe DNA onto the rGO-PDA-AuNP modified glassy carbon electrode (ssDNA/avidin/rGO-PDA-AuNP). UV-Visible, Raman, XRD, and TEM were used to evaluate the structural and morphological characteristics of rGO-PDA-AuNP. Furthermore, DNA immobilization is validated using FESEM and FT-IR techniques. The modified electrodes were electrochemically analyzed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV), and the results indicate that the produced electrode can detect target DNA up to 0.1 × 10^-7 mM with 2.12 × 10^-3 mA µM^-1 sensitivity and a response time of 5 s. The constructed genosensor displayed high sensitivity and stability, and it also provides a unique strategy for diagnosing MTB at an early stage. Furthermore, our rGO-PDA-AuNP/GCE-based electrochemical platform has broad potential for creating biosensor systems for detecting various infectious pathogens and therapeutically significant biomarkers.

Smart Graphene-Based Electrochemical Nanobiosensor for Clinical Diagnosis: Review

The technological improvement in the field of physics, chemistry, electronics, nanotechnology, biology, and molecular biology has contributed to the development of various electrochemical biosensors with a broad range of applications in healthcare settings, food control and monitoring, and environmental monitoring. In the past, conventional biosensors that have employed bioreceptors, such as enzymes, antibodies, Nucleic Acid (NA), etc., and used different transduction methods such as optical, thermal, electrochemical, electrical and magnetic detection, have been developed. Yet, with all the progresses made so far, these biosensors are clouded with many challenges, such as interference with undesirable compound, low sensitivity, specificity, selectivity, and longer processing time. In order to address these challenges, there is high need for developing novel, fast, highly sensitive biosensors with high accuracy and specificity. Scientists explore these gaps by incorporating nanoparticles (NPs) and nanocomposites (NCs) to enhance the desired properties. Graphene nanostructures have emerged as one of the ideal materials for biosensing technology due to their excellent dispersity, ease of functionalization, physiochemical properties, optical properties, good electrical conductivity, etc. The Integration of the Internet of Medical Things (IoMT) in the development of biosensors has the potential to improve diagnosis and treatment of diseases through early diagnosis and on time monitoring. The outcome of this comprehensive review will be useful to understand the significant role of graphene-based electrochemical biosensor integrated with Artificial Intelligence AI and IoMT for clinical diagnostics. The review is further extended to cover open research issues and future aspects of biosensing technology for diagnosis and management of clinical diseases and performance evaluation based on Linear Range (LR) and Limit of Detection (LOD) within the ranges of Micromolar µM (10^-6), Nanomolar nM (10^-9), Picomolar pM (10^-12), femtomolar fM (10^-15), and attomolar aM (10^-18).

Nanobiosensors Design Using 2D Materials: Implementation in Infectious and Fatal Disease Diagnosis

Nanobiosensors are devices that utilize a very small probe and any form of electrical, optical, or magnetic technology to detect and analyze a biochemical or biological process. With an increasing population today, nanobiosensors have become the broadly used electroanalytical tools for the timely detection of many infectious (dengue, hepatitis, tuberculosis, leukemia, etc.) and other fatal diseases, such as prostate cancer, breast cancer, etc., at their early stage. Compared to classical or traditional analytical methods, nanobiosensors have significant benefits, including low detection limit, high selectivity and sensitivity, shorter analysis duration, easier portability, biocompatibility, and ease of miniaturization for on-site monitoring. Very similar to biosensors, nanobiosensors can also be classified in numerous ways, either depending on biological molecules, such as enzymes, antibodies, and aptamer, or by working principles, such as optical and electrochemical. Various nanobiosensors, such as cyclic voltametric, amperometric, impedimetric, etc., have been discussed for the timely monitoring of the infectious and fatal diseases at their early stage. Nanobiosensors performance and efficiency can be enhanced by using a variety of engineered nanostructures, which include nanotubes, nanoparticles, nanopores, self-adhesive monolayers, nanowires, and nanocomposites. Here, this mini review recaps the application of two-dimensional (2D) materials, especially graphitic carbon nitride (g-C₃N₄), graphene oxide, black phosphorous, and MXenes, for the construction of the nanobiosensors and their application for the diagnosis of various infectious diseases at very early stage.

Electrochemical Biosensors Based on Carbon Nanomaterials for Diagnosis of Human Respiratory Diseases

In recent years, respiratory diseases have increasingly become a global concern, largely due to the outbreak of Coronavirus Disease 2019 (COVID-19). This inevitably causes great attention to be given to the development of highly efficient and minimal or non-invasive methods for the diagnosis of respiratory diseases. And electrochemical biosensors based on carbon nanomaterials show great potential in fulfilling the requirement, not only because of the superior performance of electrochemical analysis, but also given the excellent properties of the carbon nanomaterials. In this paper, we review the most recent advances in research, development and applications of electrochemical biosensors based on the use of carbon nanomaterials for diagnosis of human respiratory diseases in the last 10 years. We first briefly introduce the characteristics of several common human respiratory diseases, including influenza, COVID-19, pulmonary fibrosis, tuberculosis and lung cancer. Then, we describe the working principles and fabrication of various electrochemical biosensors based on carbon nanomaterials used for diagnosis of these respiratory diseases. Finally, we summarize the advantages, challenges, and future perspectives for the currently available electrochemical biosensors based on carbon nanomaterials for detecting human respiratory diseases.

Current progress of functional nanobiosensors for potential tuberculosis diagnosis: The novel way for TB control?

Tuberculosis (TB), induced by the foxy Mycobacterium tuberculosis (Mtb), is still one of the top killers worldwide among infectious diseases. Although several antibiotics have been developed to significantly relieve the tuberculosis epidemics worldwide, there are still several important scientific challenges for tuberculosis. As one of the most critical issues for tuberculosis control, the accurate and timely diagnosis of tuberculosis is critical for the following therapy of tuberculosis and thus responsible for the effective control of drug-resistant tuberculosis. Current tuberculosis diagnostic methods in clinic are still facing the difficulties that they can't provide the rapid diagnostic results with high sensitivity and accuracy, which therefore requires the development of more effective novel diagnostic strategies. In recent decades, nanomaterials have been proved to show promising potentials for novel nanobiosensor construction based on their outstanding physical, chemical and biological properties. Taking these promising advantages, nanomaterial-based biosensors show the potential to allow the rapid, sensitive and accurate tuberculosis diagnosis. Here, aiming to increase the development of more effective tuberculosis diagnostic strategy, we summarized the current progress of nanobiosensors for potential tuberculosis diagnosis application. We discussed the different kind diagnostic targets for tuberculosis diagnosis based on nanobiosensors, ranging from the detection of bacterial components from M. tuberculosis, such as DNA and proteins, to the host immunological responses, such as specific cytokine production, and to the direct whole cell detection of M. tuberculosis. We believe that this review would enhance our understandings of nanobiosensors for potential tuberculosis diagnosis, and further promote the future research on nanobiosensor-based tuberculosis diagnosis to benefit the more effective control of tuberculosis epidemic.

Tuberculosis detection from raw sputum samples using Au-electroplated screen-printed electrodes as E-DNA sensor

Tuberculosis (TB) remains a leading cause of death globally, especially in underdeveloped nations. The main impediment to TB eradication is a lack of efficient diagnostic tools for disease diagnosis. In this work, label free and ultrasensitive electrochemical DNA biosensor for detecting Mycobacterium tuberculosis has been developed based on the electrodeposition of gold nanoparticles on the surface of carbon screen-printed carbon electrode (Zensors) for signal amplification. Particularly, screen-printed electrodes were modified by electrochemical deposition of Au to enhance the conductivity and facilitate the immobilization of ssDNA probes via Au-S bonds. The electrochemically modified SPEs were characterized using Scanning electron microscopy/Energy Dispersive X-Ray Analysis (SEM/EDX) and X-Ray Diffraction (XRD). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used to investigate the DNA hybridization between single-stranded (ssDNA) probe and target DNA (tDNA). Under the ideal conditions, DPV exhibited a correlation coefficient R2 = 0.97, when analyzed with different tDNA concentrations. The proposed DNA biosensor exhibits a good detection range from 2 to 10 nm with a low detection limit of 1.91 nm, as well as high selectivity that, under ideal conditions, distinguishes non-complementary DNA from perfectly matched tDNA. By eliminating the need for DNA purification, this work paves the path for creating disposable biosensors capable of detecting DNA from raw sputum samples.

Biosensors for the detection of Mycobacterium tuberculosis: a comprehensive overview

Tuberculosis (TB) infection is one of the leading causes of death in the world. According to WHO reports 2019, the average rate of decrease in global TB incidences was only 1.6% per year from 2000 to 2018, besides that the global decline in TB deaths was just 11%. Therefore, the dire need for early detection of the pathogen for the successful diagnosis of TB seems justified. Mycobacterium tuberculosis secretory proteins have gained more attention as TB biomarkers, for the early diagnosis and treatment of TB. Here in this review, we elaborate on the recent advancements made in the field of piezoelectric, magnetic, optical, and electrochemical biosensors, in addition to listing their merits and setbacks. Additionally, this review also discusses the construction of biosensors through modern integrated technologies, such as combinations of analytical chemistry, molecular biology, and nanotechnology. Integrated technologies enhance the detection for perceiving highly selective, specific, and sensitive signals to detect M. tuberculosis. Furthermore, this review highlights the recent challenges and scope of improvement in numerous biosensors developed for rapid, specific, selective, and sensitive detection of tuberculosis to reduce the TB burden and successful treatment.

MOF-assisted antifouling material: application in rapid determination of TB gene in whole-serum specimens

Biofouling is a nuisance in the practical applications of biosensors, which seriously affects the reliability and accuracy of detection. The utilization of antifouling interface materials is a promising option for mitigating biofouling. Only highly accumulated antifouling polymeric surfaces tend to offer "zero" nonspecific protein adsorption. Herein, superior antifouling coatings based on chondroitin sulfate (CS) were prepared by the NH₂-MIL-53 (Al) assisted strategy. This is a novel design to improve the antifouling property of material by taking advantage of the high specific surface area of the three-dimensional MOF to increase the accumulation degree of antifouling functional groups per unit area. And the related chemical technology is simple and easy to operate. As expected, this novel CS-loaded MOF demonstrated an excellent antifouling performance in various biological samples, even in 100% goat serum. Only 8.48% changes of differential pulse voltammetry (DPV) were found. Furthermore, this antifouling interface material is successfully applied for the specific detection of the tuberculosis (TB) gene in undiluted biofluids. This developed TB biosensor showed a high analytical performance with a wide linear range (1.00 × 10^-16 M to 1.00 × 10^-11 M) and a low detection limit, indicating that it may open new avenues for direct biosensing of disease markers for clinical samples.

Graphene Oxide Based Electrochemical Genosensor for Label Free Detection of Mycobacterium tuberculosis from Raw Clinical Samples

Background

Mycobacterium tuberculosis’ rapid detection is still a formidable challenge to have control over the lethal disease. New diagnostic methods such as LED fluorescence microscopy, Genexpert, Interferon Gamma Release Assay (IGRA) are limited on efficacy spectrum owing to their high cost, time-intensive and laborious nature, in addition their low sensitivity hinders their robustness and portability. Electroanalytical methods are now being considered as an excellent alternative, being currently employed for efficient detection of the analytes with the potential of being portable. This report suggests label-free electrochemical detection of Mycobacterium tuberculosis (Mtb) via its marker, insertion sequence (IS6110).

Methods

In this pursuit, graphene oxide-chitosan nanocomposite (GO-CHI), a biocompatible matrix, having a large electroactive area with an overall positively charged surface, is fabricated and characterized. The obtained GO-CHI nanocomposite is then immobilized on the ITO surface to form a positively functionalized electrochemical sensor for the detection of Mtb. DNA probe, specific for the IS6110, was electrostatically anchored on a positively charged electrode surface and the resistance of charge transfer was investigated for the sensitive and specific (complementary vs non-complementary) detection of Mtb by cyclic voltammetry and differential pulse voltammetry techniques.

Results

The cyclic voltammetry was found to be diffusion controlled facilitating the absorption of analyte on the electrode surface. The label-free “genosensor” was found to detect a hybridization efficiency with a limit of detection of 3.4 pM, and correlation coefficient R²=0.99 when analysed over a range of concentrations of DNA from 7.86 pM to 94.3pM. The genosensor was also able to detect target DNA from raw sputum samples of clinical isolates without DNA purification.

Conclusion

This electrochemical genosensor provides high sensitivity and specificity; thus offering a promising platform for clinical diagnosis of TB and other infectious diseases in general.

DNA/Nano based advanced genetic detection tools for authentication of species: Strategies, prospects and limitations

Authentication, detection and quantification of ingredients, and adulterants in food, meat, and meat products are of high importance these days. The conventional techniques for the detection of meat species based on lipid, protein and DNA biomarkers are facing challenges due to the poor selectivity, sensitivity and unsuitability for processed food products or complex food matrices. On the other hand, DNA based molecular techniques and nanoparticle based DNA biosensing strategies are gathering huge attention from the scientific communities, researchers and are considered as one of the best alternatives to the conventional strategies. Though nucleic acid based molecular techniques such as PCR and DNA sequencing are getting greater successes in species detection, they are still facing problems from its point-of-care applications. In this context, nanoparticle based DNA biosensors have gathered successes in some extent but not to a satisfactory stage to mark with. In recent years, many articles have been published in the area of progressive nucleic acid-based technologies, however there are very few review articles on DNA nanobiosensors in food science and technology. In this review, we present the fundamentals of DNA based molecular techniques such as PCR, DNA sequencing and their applications in food science. Moreover, the in-depth discussions of different DNA biosensing strategies or more specifically electrochemical and optical DNA nanobiosensors are presented. In addition, the significance of DNA nanobiosensors over other advanced detection technologies is discussed, focusing on the deficiencies, advantages as well as current challenges to ameliorate with the direction for future development.

Response surface methodology optimized electrochemical DNA biosensor based on HAPNPTs/PPY/MWCNTs nanocomposite for detecting Mycobacterium tuberculosis

An important issue in the prognosis of tuberculosis (TB) is a short period between correct diagnosis and start the suitable antibiotic therapy. So, a rapid and valid method for detection of Mycobacterium tuberculosis (M. tb) complex is considered as a necessity. Herein, a rapid, low-cost, and PCR-free DNA biosensor was developed based on multi-walled carbon nanotubes (MWCNTs), polypyrrole (PPy), and hydroxyapatite nanoparticles (HAPNPs) for highly sensitive and specific recognition of M.tb. The biosensor consisted of M.tb ssDNA probe covalently attached to the HANPs/PPy/MWCNTs/GCE surface that hybridized to a complementary target sequence to form a duplex DNA. The M.tb target recognition was based on the oxidation signal of the electroactive Methylene Blue (MB) on the surface of the modified GCE using differential pulse voltammetry (DPV) method. It is worth to mention that for the first time Plackett-Burman (PB) screening design and response surface method (RSM) based on central composite design (CCD) was applied as a powerful and an efficient approach to find optimal conditions for maximum M.tb biosensor performance leading to simplicity and rapidity of operation. The proposed DNA biosensor exhibits a wide detection range from 0.25 to 200.0 nM with a low detection limit of 0.141 nM. The performance of designed biosensor for clinical diagnosis and practical applications was revealed through hybridization between DNA probe-modified GCE and extracted DNA from sputum clinical samples.

The overview and perspectives of biosensors and Mycobacterium tuberculosis: A systematic review

Tuberculosis (TB) is referred to as a "consumption" or phthisis, which has been a fatal human disease for thousands of years. Mycobacterium tuberculosis (M. tb) might have been responsible for the death of more humans than any other bacterial pathogens. Therefore, the rapid diagnosis of this bacterial infection plays a pivotal role in the timely and appropriate treatment of the patients, as well as the prevention of disease spread. More than 98% of TB cases are reported in developing countries, and due to the lack of well-equipped and specialized diagnostic laboratories, development of effective diagnostic methods based on biosensors is essential for this bacterium. In this review, original articles published in English were retrieved from multiple databases, such as PubMed, Scopus, Google Scholar, Science Direct, and Cochrane Library during January 2010-October 2019. In addition, the reference lists of the articles were also searched. Among 109 electronically searched citations, 42 articles met the inclusion criteria. The highest potential and wide usage of biosensors for the diagnosis of M. tb and its drug resistance belonged to DNA electrochemical biosensors (isoniazid and rifampin strains). Use of biosensors is expanding for the detection of resistant strains of anti-TB antibiotics with high sensitivity and accuracy, while the speed of these sensory methods is considered essential as well. Furthermore, the lowest limit of detection (0.9 fg/ml) from an electrochemical DNA biosensor was based on graphene-modified iron-oxide chitosan hybrid deposited on fluorine tin oxide for the MPT64 antigen target. According to the results, the most common methods used for M. tb detection include acid-fast staining, cultivation, and polymerase chain reaction (PCR). Although molecular techniques (e.g., PCR and real-time PCR) are rapid and sensitive, they require sophisticated laboratory and apparatuses, as well as skilled personnel and expertise in the commentary of the results. Biosensors are fast, valid, and cost-efficient diagnostic method, and the improvement of their quality is of paramount importance in resource-constrained settings.

Targeted DNA complementation on a 1,1'-carbonyldiimidazole-functionalized surface for identifying Mycobacterium tuberculosis

Herein, a rapid and sensitive current-volt measurement was developed for identifying the IS6110 DNA sequence to diagnose Mycobacterium tuberculosis (TB). An aminated capture probe was immobilized on a 1,1'-carbonyldiimidazole-functionalized interdigitated electrode (IDE) silica substrate, and the target sequence was detected by complementation. It was found that all tested concentrations displayed a higher response in current changes than the control, and the limit of detection was 10 fM. The sensitivity ranged from 1 to 10 fM. The control sequences with single-, triple-mismatch and noncomplementary sequences showed great discrimination. This rapid and easy DNA detection method helps to identify M. tuberculosis for early-stage diagnosis of TB.

Nanoscale dynamic chemical, biological sensor material designs for control monitoring and early detection of advanced diseases

Early detection and easy continuous monitoring of emerging or re-emerging infectious, contagious or other diseases are of particular interest for controlling healthcare advances and developing effective medical treatments to reduce the high global cost burden of diseases in the backdrop of lack of awareness regarding advancing diseases. Under an ever-increasing demand for biosensor design reliability for early stage recognition of infectious agents or contagious diseases and potential proteins, nanoscale manufacturing designs had developed effective nanodynamic sensing assays and compact wearable devices. Dynamic developments of biosensor technology are also vital to detect and monitor advanced diseases, such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), diabetes, cancers, liver diseases, cardiovascular diseases (CVDs), tuberculosis, and central nervous system (CNS) disorders. In particular, nanoscale biosensor designs have indispensable contribution to improvement of health concerns by early detection of disease, monitoring ecological and therapeutic agents, and maintaining high safety level in food and cosmetics. This review reports an overview of biosensor designs and their feasibility for early investigation, detection, and quantitative determination of many advanced diseases. Biosensor strategies are highlighted to demonstrate the influence of nanocompact and lightweight designs on accurate analyses and inexpensive sensing assays. To date, the effective and foremost developments in various nanodynamic designs associated with simple analytical facilities and procedures remain challenging. Given the wide evolution of biosensor market requirements and the growing demand in the creation of early stage and real-time monitoring assays, precise output signals, and easy-to-wear and self-regulating analyses of diseases, innovations in biosensor designs based on novel fabrication of nanostructured platforms with active surface functionalities would produce ​remarkable biosensor devices. This review offers evidence for researchers and inventors to focus on biosensor challenge and improve fabrication of nanobiosensors to revolutionize consumer and healthcare markets.

DNA markers and nano-biosensing approaches for tuberculosis diagnosis

According to WHO 2018 report, 10 million people developed tuberculosis and 1.3 million died from it making it 1 of 10 deadliest diseases worldwide. Tuberculosis is caused by infection with the bacillus Mycobacterium tuberculosis (Mtb). WHO recommends using a specific diagnostic kit Xpert MTB/RIF developed by Cepheid (California, United States). An alarming number of new cases (ca. 558,000) of rifampicin-resistant tuberculosis was diagnosticated in 2017. In recent years, new diagnosis tools targeting the Mtb DNA biomarkers have emerged using a plethora of nanomaterials capable of delivering new technological approaches for the rapid diagnostics of TB and rifampicin-resistant TB (RR-TB). In this chapter, we summarized the state-of-the-art of the current available DNA biomarkers and the potential applications for the development of new diagnosis nanotechnology-based devices. The latter use carbonaceous nanomaterials (graphene and carbon nanotubes), noble metals (silver and gold), semi-conducting (metal oxides, magnetic beads, and quantum dots) in order to reveal and/or to amplify the signal after the recognition of target DNA biomarker. The readout techniques such as colorimetry, fluorescence, surface plasmon resonance, and electrochemical methods were also reviewed. Future is bright for point-of-care diagnostics with a sample-in answer-out approach that hampers user-error through miniaturization of biochip technology to the nanoscale range, which will enable their use by nonspecialized personnel.

Recent progress in nanomaterial-based electrochemical biosensors for pathogenic bacteria

This review (with 118 refs.) discusses the progress made in electroanalytical methods based on the use of organic and inorganic nanomaterials for the determination of bacteria, specifically of E. coli, Salmonella, Staphylococcus, Mycobacterium, Listeria and Klebsiella species. We also discuss advantages and limitations of electrochemical methods. Strategies based on the use of aptamers, DNA and antibodies are covered. Following an introduction into electrochemical biosensing, a first large section covers methods for pathogen detection using metal nanoparticles, with subsections on silver nanoparticles, gold nanoparticles, magnetic nanoparticles and carbon-based nanomaterials. A second large section covers methods based on the use of organic nanocomposites, graphene and its derivatives. Other nanoparticles are treated in a final section. Several tables are presented that give an overview on the wealth of methods and materials. A concluding section summarizes the current status, addresses challenges, and gives an outlook on potential future trends. Graphical abstract This review demonstrates the progress made in electroanalytical methods based on the use of organic and inorganic nanomaterials for the detection and determination of pathogenic bacteria. We also discuss advantages and limitations of electrochemical methods. Strategies based on the use of aptamers, DNA and antibodies are covered.

Electrochemical sensors and biosensors based on the use of polyaniline and its nanocomposites: a review on recent advances

Polyaniline and its composites with nanoparticles have been widely used in electrochemical sensor and biosensors due to their attractive properties and the option of tuning them by proper choice of materials. The review (with 191 references) describes the progress made in the recent years in polyaniline-based biosensors and their applications in clinical sensing, food quality control, and environmental monitoring. A first section summarizes the features of using polyaniline in biosensing systems. A subsequent section covers sensors for clinical applications (with subsections on the detection of cancer cells and bacteria, and sensing of glucose, uric acid, and cholesterol). Further sections discuss sensors for use in the food industry (such as for sulfite, phenolic compounds, acrylamide), and in environmental monitoring (mainly pesticides and heavy metal ions). A concluding section summarizes the current state, highlights some of the challenges currently compromising performance in biosensors and nanobiosensors, and discusses potential future directions. Graphical abstract Schematic presentation of electrochemical sensor and biosensors applications based on polyaniline/nanoparticles in various fields of human life including medicine, food industry, and environmental monitoring. The simultaneous use of suitable properties polyaniline and nanoparticles can provide the fabrication of sensing systems with high sensitivity, short response time, high signal/noise ratio, low detection limit, and wide linear range by improving conductivity and the large surface area for biomolecules immobilization.

A review on graphene-based nanocomposites for electrochemical and fluorescent biosensors

Biosensors with high sensitivity, selectivity and a low limit of detection, reaching nano/picomolar concentrations of biomolecules, are important to the medical sciences and healthcare industry for evaluating physiological and metabolic parameters.

A repertoire of biomedical applications of noble metal nanoparticles

The emerging properties of noble metal nanoparticles are attracting huge interest from the translational scientific community. In this feature article, we highlight recent advances in the adaptation of noble metal nanomaterials and their biomedical applications in therapeutics, diagnostics and sensing.

Sandwich Electrochemical Immunosensor for Early Detection of Tuberculosis Based on Graphene/Polyaniline-Modified Screen-Printed Gold Electrode

A rapid and sensitive sandwich electrochemical immunosensor was developed based on the fabrication of the graphene/polyaniline (GP/PANI) nanocomposite onto screen-printed gold electrode (SPGE) for detection of tuberculosis biomarker 10-kDa culture filtrate protein (CFP10). The prepared GP/PANI nanocomposite was characterized using Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). The chemical bonding and morphology of GP/PANI-modified SPGE were studied by Raman spectroscopy and FESEM coupled with energy dispersive X-ray spectroscopy, respectively. From both studies, it clearly showed that GP/PANI was successfully coated onto SPGE through drop cast technique. Cyclic voltammetry was used to study the electrochemical properties of the modified electrode. The effective surface area for GP/PANI-modified SPGE was enhanced about five times compared with bare SPGE. Differential pulse voltammetry was used to detect the CFP10 antigen. The GP/PANI-modified SPGE that was fortified with sandwich type immunosensor exhibited a wide linear range (20⁻100 ng/mL) with a low detection limit of 15 ng/mL. This proposed electrochemical immunosensor is sensitive, low sample volume, rapid and disposable, which is suitable for tuberculosis detection in real samples.

Aptamer immobilization on amino-functionalized metal-organic frameworks: an ultrasensitive platform for the electrochemical diagnostic of Escherichia coli O157:H7

Herein, we report the development of an electrochemical biosensor for Escherichia coli O157:H7 diagnostic based on amino-functionalized metal-organic frameworks (MOFs) as a new generation of organic-inorganic hybrid nanocomposites. The electrical and morphological properties of MOFs were enhanced by interweaving each isolated MOF crystal with polyaniline (PANI). Subsequent attachment of the amine-modified aptamer to the polyanilinated MOFs was accomplished using glutaraldehyde (GA) as a cross-linking agent. The prepared biocompatible platform was carefully characterized by means of field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray powder diffraction (XRD) techniques. The biosensor fabrication and its electrochemical characterizations were monitored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Differential pulse voltammetry (DPV) was applied to monitoring and quantitation of the interaction between the aptamer and E. coli O157:H7 using methylene blue (MB) as an electrochemical indicator. Changes in the reduction peak current of MB in the presence of E. coli O157:H7 was recorded as an analytical signal and indicated a relationship with the logarithm of the E. coli O157:H7 concentration in the range of 2.1 × 10¹ to 2.1 × 10⁷ CFU mL^-1 with a LOQ of 21 CFU mL^-1 and LOD of 2 CFU mL^-1. The electrochemical aptasensor displayed good recovery values for the detection of E. coli O157:H7 in environmental real samples and also could act as a smart device to investigate the effects of antibacterial agents against E. coli O157:H7.

Recent technological advancements in tuberculosis diagnostics - A review

Early diagnosis and on-time effective treatment are indispensable for Tuberculosis (TB) control - a life threatening infectious communicable disease. The conventional techniques for diagnosing TB normally take two to three weeks. This delay in diagnosis and further increase in detection complexity due to the emerging risks of XDR-TB (Extensively drug Resistant-TB) and MDR-TB (Multidrug Resistant-TB) are evoking interest of researchers in the field of developing rapid TB detection techniques such as biosensing and other point-of-care (POC) techniques. Biosensing technologies along with the collaboration with nanotechnology have enormous potential to boost the MTB detection and for overall management in clinical diagnosis. A diverse range of portable, sensitive and rapid biosensors based on different signal transducer principles and with different biomarkers detection capabilities have been developed for TB detection in the early stages. Further, a lot of progress has been achieved over the years in developing various point-of-care diagnostic tools including non-molecular methods and molecular techniques. The objective of this study is to present a succinct review of the available TB detection techniques that are either in use or under development. The focus of this review is on the current developments occurred in nano-biosensing technologies. A synopsis of ameliorations in different non-molecular diagnostic tools and progress in the field of molecular techniques along with the role of emerging Lab-on-Chip technology for diagnosing and mitigating the TB consequences have also been presented.

Voltammetric determination of the Escherichia coli DNA using a screen-printed carbon electrode modified with polyaniline and gold nanoparticles

The authors describe an electrochemical assay for fast detection of Escherichia coli (E. coli). It is based on a dual signal amplification strategy and the use of a screen-printed carbon electrode (SPCE) whose surface was modified with a polyaniline (PANI) film and gold nanoparticles (AuNPs) via cyclic voltammetry (CV). In the next step, avidin was covalently immobilized on the PANI/AuNP composite on the SPCE surface. Subsequently, the biotinylated DNA capture probe was immobilized onto the PANI/AuNP/avidin-modified SPCE by biotin-avidin interaction. Then, DNA of E.coli, digoxigenin-labeled DNA detector probe and anti-digoxigenin-labeled horseradish peroxidase (HRP) were placed on the electrode. 3,3',5,5'-Tetramethylbenzidine (TMB) and H₂O₂ solution were added and the CV electrochemical signal was generated at a potential of -0.1 V (vs. Ag/AgCl) and a scan rate 50 mV.s^-1. The assay can detect 4 × 10⁶ to 4 CFU of E. coli without DNA amplification. The biosensor is highly specific over other pathogens including Klebsiella pneumoniae, Proteus mirabilis, Enterococcus faecalis, Staphylococcus haemolyticus and Pseudomonas aeruginosa. It can be concluded that this genosensor has an excellent potential for rapid and accurate diagnosis of E.coli inflicted infections. Graphical Abstract Schematic of an electrochemical E. coli genosensor based on sandwich assay on a polyaniline/gold nanoparticle-modified screen printed carbon electrode (SPCE). The biosensor can detect 4 × 10⁶ to 4 CFU of E. coli without DNA amplification.

Synthesis of gold-palladium nanowaxberries/dodecylamine-functionalized graphene quantum dots-graphene micro-aerogel for voltammetric determination of peanut allergen Ara h 1

The paper reports synthesis of gold-palladium nanowaxberries(AuPd NWs)/dodecylamine-functionalized graphene quantum dots(D-GQDs)-graphene micro-aerogel(GMA). D-GQDs was used as a solid particle surfactant for stabilizing Pickering emulsion of toluene-in-graphene oxide aqueous dispersion. Graphene oxide sheets in the aqueous phase are reduced by hydrazine hydrate, diffused into the toluene droplet and self-assembled into graphene oxide micro-gels. Followed by freeze-drying, thermal annealing and hybridized with AuPd NWs. The as-prepared AuPd NWs/D-GQDs-GMA shows an unique three-dimensional structure with the size of microns. The small size and strong polarity make it can be directly dispersed in ethanol to form stable dispersion for sensor preparation. The hybrid of GMA, D-GQDs and AuPd NWs greatly improves the electron transfer, electroactive surface area and ion diffusion. The architecture of conductor/semiconductor/conductor achieves to a significant amplification of detection signal. The DNA biosensor based on the AuPd NWs/D-GQDs-GMA exhibits ultrasensitive differential pulse voltammetric (DPV) response towards peanut allergen Ara h 1. The DPV signal linearly increases with increasing DNA concentration in the range of 1.0 × 10^-22-1.0 × 10^-17 M with the detection limit of 4.7 × 10^-23 M (S/N = 3). The analytical method was successfully applied to voltammetric determination of peanut allergen Ara h 1 in peanut milk beverage.

Simultaneous detections of genetic fragment and single nucleotide mutation with a three-tiered output for tuberculosis diagnosis

Tuberculosis (TB) remains one of the major infectious diseases worldwide. The pathogenic bacterium, Mycobacterium tuberculosis (M.tb), continuously evolves strains carrying drug-resistance genes, thus posing a growing challenge to TB prevention and treatment. We report a diagnostic system that uses a molecular beacon probe and an assistant strand as the core to simultaneously interact with an M.tb-specific fragment (in IS6110) and a single nucleotide substitution (SNS)-encoded segment (in rpoB) associated with drug resistance. A single fluorescent output in three-tiered levels was produced for combinatorial interpretations based on formation of a four-way DNA junction (4WJ). The SNS caused the 4WJ to partially dissociate, thus resulting in medium-level fluorescence. By contrast, high- and low-level fluorescence, represented the complete complementary complex and absence of either targeted fragments, respectively. Manipulating the length of the analyte-binding arm realized the medium output. The thermodynamics and kinetics of 4WJ construction were investigated to maximize the tiered-output performance. Biocatalytic amplification driven by the Klenow Fragment and Nt.AlwI was incorporated into the method to enhance the signal 64-fold and ensure long-term stability of the three-tiered output. The detection accuracy of the sensing system was verified using unpurified amplicons with templates of extracted DNA and boiled bacterial solutions. The tiered-output mechanism was usable at bacterial loads ranging from 4 × 10⁰ to 4 × 10³ CFU per reaction. The interference caused by nontuberculous mycobacteria was minimal. The results demonstrated the integrity of the sensing method as an alternative strategy for rapid screening of M.tb and detecting rifampin-resistance.

Synthesis and Characterization of Polyaniline/Graphene Composite Nanofiber and Its Application as an Electrochemical DNA Biosensor for the Detection of Mycobacterium tuberculosis

This article describes chemically modified polyaniline and graphene (PANI/GP) composite nanofibers prepared by self-assembly process using oxidative polymerization of aniline monomer and graphene in the presence of a solution containing poly(methyl vinyl ether-alt-maleic acid) (PMVEA). Characterization of the composite nanofibers was carried out by Fourier transform infrared (FTIR) and Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). SEM images revealed the size of the PANI nanofibers ranged from 90 to 360 nm in diameter and was greatly influenced by the proportion of PMVEA and graphene. The composite nanofibers with an immobilized DNA probe were used for the detection of Mycobacterium tuberculosis by using an electrochemical technique. A photochemical indicator, methylene blue (MB) was used to monitor the hybridization of target DNA by using differential pulse voltammetry (DPV) method. The detection range of DNA biosensor was obtained from of 10⁻⁶–10⁻⁹ M with the detection limit of 7.853 × 10⁻⁷ M under optimum conditions. The results show that the composite nanofibers have a great potential in a range of applications for DNA sensors.

Carbon Nanomaterials in Biological Studies and Biomedicine

The "carbon nano-world" has made over the past few decades huge contributions in diverse scientific disciplines and technological advances. While dramatic advances have been widely publicized in using carbon nanomaterials such as fullerenes, carbon nanotubes, and graphene in materials sciences, nano-electronics, and photonics, their contributions to biology and biomedicine have been noteworthy as well. This Review focuses on the use of carbon nanotubes (CNTs), graphene, and carbon quantum dots [encompassing graphene quantum dots (GQDs) and carbon dots (C-dots)] in biologically oriented materials and applications. Examples of these remarkable nanomaterials in bio-sensing, cell- and tissue-imaging, regenerative medicine, and other applications are presented and discussed, emphasizing the significance of their unique properties and their future potential.

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.

Graphene-Gold Nanoparticles Hybrid-Synthesis, Functionalization, and Application in a Electrochemical and Surface-Enhanced Raman Scattering Biosensor

Graphene is a single-atom-thick two-dimensional carbon nanosheet with outstanding chemical, electrical, material, optical, and physical properties due to its large surface area, high electron mobility, thermal conductivity, and stability. These extraordinary features of graphene make it a key component for different applications in the biosensing and imaging arena. However, the use of graphene alone is correlated with certain limitations, such as irreversible self-agglomerations, less colloidal stability, poor reliability/repeatability, and non-specificity. The addition of gold nanostructures (AuNS) with graphene produces the graphene-AuNS hybrid nanocomposite which minimizes the limitations as well as providing additional synergistic properties, that is, higher effective surface area, catalytic activity, electrical conductivity, water solubility, and biocompatibility. This review focuses on the fundamental features of graphene, the multidimensional synthesis, and multipurpose applications of graphene-Au nanocomposites. The paper highlights the graphene-gold nanoparticle (AuNP) as the platform substrate for the fabrication of electrochemical and surface-enhanced Raman scattering (SERS)-based biosensors in diverse applications as well as SERS-directed bio-imaging, which is considered as an emerging sector for monitoring stem cell differentiation, and detection and treatment of cancer.

Biosensor-based detection of tuberculosis

Tuberculosis (TB), caused byMycobacterium tuberculosis(M.tb.), is one of the most prevalent and serious infectious diseases worldwide with an estimated annual global mortality of 1.4 million in 2010.