This article developed a novel electrochemical immunosensor for the specific detection of aflatoxin B1 (AFB1). Amino‐functionalized iron oxide nanoparticles (Fe3O4‐NH2) were synthesized. Fe3O4‐NH2 ...were chemically bound on self‐assembly monolayers (SAMs) of mercaptobenzoic acid (MBA). Finally, polyclonal antibodies (pAb) were immobilized on Fe3O4‐NH2‐MBA. The sensor system was evaluated through atomic force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). A reduction in the anodic and cathodic peak currents was observed after the assembly of the sensor platform. The charge transfer resistance (Rct) was increased due to the electrically insulating bioconjugates. Then, the specific interaction between the sensor platform and AFB1 blocks the electron transfer of the Fe(CN)63−/4− redox pair. The nanoimmunosensor showed a linear response range estimated from 0.5 to 30 μg/mL with a limit of detection (LOD) of 9.47 μg/mL and a limit of quantification (LOQ) of 28.72 μg/mL for AFB1 identification in a purified sample. In addition, a LOD of 3.79 μg/mL, a LOQ of 11.48 μg/mL, and a regression coefficient of 0.9891 were estimated for biodetection tests on peanut samples. The proposed immunosensor represents a simple alternative, successfully applied in detecting AFB1 in peanuts, and therefore, represents a valuable tool for ensuring food safety.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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•An electrochemical biodevice was developed to identify the BCR/ABL fusion gene.•A new interface platform was designed from polypyrrole and hybrid nanostructures.•Clinical samples ...from patients with chronic myeloid leukemia were investigated in bioassays.•The sensing system showed a limit of detection of 0.52 fM with high selectivity.•The bioanalysis technology contributes to the rapid and early diagnosis of cancer.
The present research refers to elaborating a new label-free electrochemical biosensor used to detect the BCR/ABL fusion gene. We used a hybrid nanocomposite composed of chitosan and zinc oxide nanoparticles (Chit-ZnONP) immobilized on a polypyrrole (PPy) film. DNA segments were covalently immobilized, allowing biomolecular recognition. Atomic force microscopy (AFM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used to evaluate the assembly stages of the biosensor. The biosensor’s analytical performance was investigated using recombinant plasmids containing the target oncogene and clinical samples from patients with chronic myeloid leukemia (CML). A limit of detection (LOD) of 1.34 fM, limit of quantification (LOQ) of 4.08 fM, and sensitivity of 34.03 μA fM−1 cm2 were calculated for the BCR/ABL fusion oncogene. The sensing system exhibited high specificity, selectivity, and reproducibility with a standard deviation (SD) of 4.21%. Additionally, a linear response range was observed between 138.80 aM to 13.88 pM with a regression coefficient of 0.96. Also, the biosensor shows easy operationalization and fast analytical response, contributing to the early cancer diagnosis. The proposed nanostructured device is an alternative for the genetic identification BCR/ABL fusion gene.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Considering the low sensitivity of cytological exams and high costs of the molecular methods, the development of diagnostic tests for effective diagnosis of HPV infections is a priority. In this ...work, biosensor composed of polypyrrole (PPy) films and gold nanoparticles (AuNPs) was obtained for specific detection of HPV genotypes. The biosensor was developed by using flexible electrodes based on polyethylene terephthalate (PET) strips coated with indium tin oxide (ITO). Polymeric films and AuNPs were obtained by electrosynthesis. Oligonucleotides sequences modified with functional amino groups were designed to recognize HPV gene families strictly. The modified oligonucleotides were chemically immobilized on the nanostructured platform. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the analysis of the electrode modification and monitoring of molecular hybridization. Electrochemical changes were observed after exposure of the biosensors to plasmid samples and cervical specimens. The biosensor based on the BSH16 probe showed a linear concentration range for target HPV16 gene detection of 100 pg μL−1 to 1 fg μL−1. A limit of detection (LOD) of 0.89 pg μL−1 and limit of quantification (LOQ) of 2.70 pg μL−1 were obtained, with a regression coefficient of 0.98. Screening tests on cervical specimens were performed to evaluate the sensibility and specificity for HPV and its viral family. The expression of a biomarker for tumorigenesis (p53 gene) was also monitored. In this work, a flexible system has been successfully developed for label-free detection of HPV families and p53 gene monitoring with high specificity, selectivity, and sensitivity.
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•A novel strutured platform was proposed for HPV detection in clinical specimens.•Flexible electrodes were modified with polypyrrole films and gold nanoparticles.•Oligonucleotides sequences were designed to recognize HPV gene families.•HPV diagnosis was correlated with the p53 gene, a tumorigenesis biomarker.•The biosensor showed a limit of detection of 0.89 pg μL−1 with high selectivity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Systemic sclerosis (SSc) is a chronic, autoimmune disease that primarily affects connective tissue. SSc can be classified into limited cutaneous (lSSc) and diffuse cutaneous (dSSc). Oncostatin M ...receptor (sOSMR) is an important inflammatory biomarker expressed in the serum of patients with autoimmune diseases. A nanoengineered immunosensor surface was developed. The biosensor was composed of a conductive layer of polypyrrole, electrodeposited gold nanoparticles, and sOSMR protein for anti-human OSMR monoclonal antibody biorecognition. The electrochemical response evaluated by cyclic voltammetry and electrochemical impedance spectroscopy indicated the detection of the target analyte present in clinical samples from lSSc and dSSc patients. The voltammetric anodic shift for lSSc specimens was 82.7% ± 0.9–93.6% ± 3.2, and dSSc specimens was 118.7 ± 2.6 to 379.6 ± 2.6, revealing a differential diagnostic character for SSc subtypes. The sensor platform was adapted for identifying sOSMR, using anti-OSMR antibodies as bioreceptors. With a linear response range estimated from 0.005 to 500 pg mL−1 and a limit of detection of 0.42 pg mL−1, the sensing strategy demonstrated high sensitivity in identifying the human OSMR protein in clinical samples. The proposed biosensor is a promising and innovative tool for SSc-related biomarker research.
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•An innovative nanoimmunosensor applicable to systemic sclerosis was developed.•Flexible transducers were modified with polypyrrole films and gold nanoparticles.•Anti-OSMR antibodies and sOSMR protein were detected in clinical specimens.•Sclerosis diagnosis was correlated with diffuse and limited subtypes of the disease.•The sensor exhibited a limit of detection of 0.42 pg mL−1 with high selectivity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A label-free flexible biodevice applicable to COVID-19 was developed.•Flexible transducers were modified with polypyrrole films and gold nanoparticles.•The sensor showed a limit of detection of ...258.01 copies µL−1 with high selectivity.•The resistance variation was associated with the cycle threshold value of RT-PCR.•SARS-CoV-2 diagnosis was correlated with various stages of the viral infection.
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The projection of new biosensing technologies for genetic identification of SARS-COV-2 is essential in the face of a pandemic scenario. For this reason, the current research aims to develop a label-free flexible biodevice applicable to COVID-19. A nanostructured platform made of polypyrrole (PPy) and gold nanoparticles (GNP) was designed for interfacing the electrochemical signal in miniaturized electrodes of tin-doped indium oxide (ITO). Oligonucleotide primer was chemically immobilized on the flexible transducers for the biorecognition of the nucleocapsid protein (N) gene. Methodological protocols based on cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM) were used to characterize the nanotechnological apparatus. The biosensor’s electrochemical performance was evaluated using the SARS-CoV-2 genome and biological samples of cDNA from patients infected with retrovirus at various disease stages. It is inferred that the analytical tool was able to distinguish the expression of SARS-CoV-2 in patients diagnosed with COVID-19 in the early, intermediate and late stages. The biosensor exhibited high selectivity by not recognizing the biological target in samples from patients not infected with SARS-CoV-2. The proposed sensor obtained a linear response range estimated from 800 to 4000 copies µL−1 with a regression coefficient of 0.99, and a detection limit of 258.01 copies µL−1. Therefore, the electrochemical biosensor based on flexible electrode technology represents a promising trend for sensitive molecular analysis of etiologic agent with fast and simple operationalization. In addition to early genetic diagnosis, the biomolecular assay may help to monitor the progression of COVID-19 infection in a novel manner.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•A label-free DNA biosensor based metal-polymer hybrid nanomaterial was developed.•An impedimetric tool for the diagnosis of HPV in cervical specimens was obtained.•The use of the ...MY11 probe was reported for identification of HPV genotypes.•3D analysis showed a pattern of association for samples of high oncogenic risk.•A detection limit in the order of picogram per microliter was estimated.
The human papillomavirus (HPV) is one of the main sexually transmitted pathogens that infect the anogenital epithelium and mucous membranes. HPV genotypes can be classified as high and low oncogenic risk, with infection by the former resulting in cervical cancer in approximately 100 % of the cases. In this work, we developed an ultrasensitive electrochemical biosensor for the detection and identification of different HPV genotypes. A nanostructured platform based on a matrix of polyaniline (PANI) containing gold nanoparticles (AuNps) was designed for the chemical immobilization of a DNA probe capable of recognizing different HPV types. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM) were used to characterize the genosensor. The impedimetric responses indicate that the proposed sensor was able to detect HPV (types 6, 11, 16, 31, 33, 45, and 58) in cervical specimens (cDNA samples). We obtained different profiles of electrochemical responses for the high and low-risk HPV genotypes. By adopting a three-dimensional quantitative analysis of impedance response variables, it was possible to identify the existence of a pattern of association for samples of high oncogenic risk, which may lead to the differential diagnosis of HPV. The biosensor demonstrated an excellent analytical performance for the detection of HPV genotypes with high sensibility and selectivity. The genosensor exhibited a linear range of response in the 1 pg μL−1 to 100 pg μL−1 range. Besides, a limit of detection (LOD) of 2.74 pg μL−1 and 7.43 pg μL−1 was obtained for HPV11 and HPV16, respectively, with regression coefficients of 99.88 % and 99.47 %. Thus, the proposed sensor may serve as a good prognostic indicator for patients infected with papillomavirus.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A sensor platform consisting of MBA modified AuNps was successfully synthesized.•A platform for anti-DENV antibodies immobilization was obtained.•Four different immunosensors for specific detection ...of DENV-(1-4) were obtained.•We obtained a sensor with high sensitivity, selectivity, and operational simplicity.
Currently, Dengue is a worldwide health problem and no effective vaccine or specific medication. Thus, the development of new diagnostic methods has been the focus of efforts to combat the disease. Immunosensor based on gold nanoparticles (AuNPs) and self-assembled monolayers of cysteine was developed for dengue virus (DENV-1, DENV-2, DENV-3 and DENV-4) detection. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to monitor the signal response of the each dengue serotype in different dilutions. Scanning electron microscopy was used to characterize the surface of the immunosensor before and after exposure to DENV. In this work, four different immunosensors with specificity for DENV1-4 were obtained. EIS and CV measurements demonstrate the ability of the immunosensor to recognize all four studied DENV serotypes showing sensitivity and selectivity. The real part of the impedance was higher for Cys–MBA–AuNPs–anti-DENV antibody sensor system after interaction to different concentrations of DENV (1-4) compared to the sensor system without immunoreaction on their surface, revealing an increased blockage of the electron transfer. In addition, the surface coverage values indicate a good recognition of DENV by anti-DENV antibody. The new sensor platform consists of a single method, more affordable than conventional immunoassays and creates expectation on future production of new real-time devices for diagnosis of pathologies caused by virus.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The conventional methodologies used for the detection of human papillomavirus (HPV) present actually robust and reproducible advantages. However, at the same time, they involve complex protocols that ...sometimes are difficult to popularize. Over the first half of XX century, the adequate treatment of complex and delicate processes from a simple instrumental base seemed a fundamental and intrinsic contradiction. However, interdisciplinary trends have allowed the manipulation of tissues, proteins, and nucleic acids through innovative increasingly smaller devices. The proper diagnosis of HPV has seen great advances since biosensor researchers are employing its virus strains as models to study the interactions between the biorecognition element and the transducer. Additionally, all recent improvements and trends that material sciences, biotechnology, and data processing scientists excel for biosensors can be applied for the HPV detection platforms. In this review, we highlight the recent trends on materials, nanomaterials, and transducers for the specific detection and differentiation of HPV strains. The most influential methods for the detection and identification of these papillomaviruses include optical, electrochemical, and piezoelectric transducers; we will visit their sensibility and advantages. Additionally, we highlight the factors that contributed to the increasing importance of these biodevices as potential substitutes to conventional diagnostic methods.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Antimicrobial peptides (AMPs) are natural compounds isolated from a wide variety of organisms that include microorganisms, insects, amphibians, plants, and humans. These biomolecules are considered ...as part of the innate immune system and are known as natural antibiotics, presenting a broad spectrum of activities against bacteria, fungi, and/or viruses. Technological innovations have enabled AMPs to be utilized for the development of novel biodetection devices. Advances in nanotechnology, such as the synthesis of nanocomposites, nanoparticles, and nanotubes have permitted the development of nanostructured platforms with biocompatibility and greater surface areas for the immobilization of biocomponents, arising as additional tools for obtaining more efficient biosensors. Diverse AMPs have been used as biological recognition elements for obtaining biosensors with more specificity and lower detection limits, whose analytical response can be evaluated through electrochemical impedance and fluorescence spectroscopies. AMP-based biosensors have shown potential for applications such as supplementary tools for conventional diagnosis methods of microorganisms. In this review, conventional methods for microorganism diagnosis as well new strategies using AMPs for the development of impedimetric and fluorescent biosensors are highlighted. AMP-based biosensors show promise as methods for diagnosing infections and bacterial contaminations as well as applications in quality control for clinical analyses and microbiological laboratories.
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•An electrochemical DNA sensor based on a nanostructured polyaniline-gold composite was developed.•A simple and attractive tool for the molecular diagnosis of the BCR/ABL oncogene was ...obtained.•The new hybrid sensing-platform displayed high specificity and selectivity.•The device exhibited an excellent detection limit estimated to be as low as 69.4 aM.
In the last ten years, conjugated polymers started to be used in the immobilization of nucleic acids via non-covalent interactions. In the present study, we describe the construction and use of an electrochemical DNA biosensor based on a nanostructured polyaniline-gold composite, specifically developed for the detection of the BCR/ABL chimeric oncogene. This chromosome translocation is used as a biomarker to confirm the clinical diagnosis of both chronic myelogenous leukemia (CML) and acute lymphocytic leukemia (ALL). The working principle of the biosensor rests on measuring the conductivity resulting from the non-covalent interactions between the hybrid nanocomposite and the DNA probe. The nanostructured platform exhibits a large surface area that enhances the conductivity. Positive cases, which result from the hybridization between DNA probe and targeted gene, induce changes in the amperometric current and in the charge transfer resistance (RCT) responses. Atomic force microscopy (AFM) images showed changes in the genosensor surface after exposure to cDNA sample of patient with leukemia, evidencing the hybridization process. This new hybrid sensing-platform displayed high specificity and selectivity, and its detection limit is estimated to be as low as 69.4 aM. The biosensor showed excellent analytical performance for the detection of the BCR/ABL oncogene in clinical samples of patients with leukemia. Hence, this electrochemical sensor appears as a simple and attractive tool for the molecular diagnosis of the BCR/ABL oncogene even in early-stage cases of leukemia and for the monitoring of minimum levels of residual disease.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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