Rapid and practical colorimetric biosensor for leishmaniasis diseases.

In this article, a colorimetric biosensor for detection of Leishmania major surface protease (Gp63) antibody (anti-gp63) was developed by using gold nanoparticle (AuNP) as a color reagent. The dispersion or aggregation of AuNPs leads to a distinct and sensitive change in UV-vis spectra and solution color. For this purpose, kinetoplastid membrane protein-11 (KMP-11) was labeled with AuNPs surface directly. After that, Gp63 antibody was added in the KMP-11@AuNP solution and a color change from red/pink to purple/violet was observed. As a result, anti-gp63 solution diluted at a ratio of 1:640 can be detected with the developed colorimetric leishmania biosensor. The relative standard deviation value for 1:320 diluted anti-gp63 was calculated as 1.29 %. Furthermore, the linear range of the developed colorimetric biosensor was determined as 1:80 to 1:640. Moreover, developed Leishmania biosensor was applied for detection of leishmania parasite crude antigen and rabbit serum which were used as positive and negative samples respectively. As a result, the recovery values for the measurements of aforementioned samples were calculated as 95.3 % ± 0.02, 103.1 % ± 0.02, 96.2 % ± 0.01 and 95.5 % ± 0.03 for dilutions of 1:200, 1:160, 1:320 and 1:640 anti-gp63 solutions respectively.

Electrochemical Immunoassay Platform for Human Monkeypox Virus Detection.

In this study, we reported a selective impedimetric biosensor for the detection of A29 which is the target protein of the monkeypox virus (MPXV). The working principle of the biosensor relies on the interaction mechanism between A29, which is an internal membrane protein of MPXV, and the heparan sulfate receptor. For this purpose, after immobilizing heparan sulfate onto the gold screen-printed electrode surface, its interaction with A29 protein was monitored using electrochemical impedance spectroscopy. After the optimization of experimental parameters, the analytical characteristics of the developed MPVX immunosensor were examined. The developed immunosensor exhibited a linear detection range between 2.0 and 50 ng mL-1, with a detection limit of 2.08 ng mL-1 and a quantification limit of 6.28 ng mL-1. Furthermore, a relative standard deviation value of 2.82% was determined for 25 ng mL-1. Apart from that, sample application studies were also performed with the standard addition of A29 protein to 1:10 diluted real serum samples that were taken from healthy individuals, and very good recovery values were obtained.

Copper based metal organic framework decorated with gold nanoparticles as a new electrochemical sensor material for the detection of L-Cysteine in milk samples.

A facile electrochemical sensor based on carbon felt electrode (CFE) modified with gold nanoparticles decorated copper based metal organic framework (AuNPs@Cu-MOF) was achieved for the electrochemical sensing of L-Cysteine (L-Cys). For this purpose, AuNPs@Cu-MOF was synthesized and characterized. The electrochemical behaviors of L-Cys at plain and modified CFEs were investigated via cyclic voltammetry (CV). According CV results, AuNPs@Cu-MOF structure showed a catalytic effect on the oxidation of L-Cys as well as increasing the active electrode surface area by 206% compared to bare CFE. In addition, the pH effect on electrochemical determination of L-Cys at AuNPs@Cu-MOF/CFE was widely examined, and it was determined that the best oxidation peak current of L-Cys was obtained in pH 5 acetate buffer. Moreover, a linear detection range of 30-400 µM for L-Cys with a limit of detection value of 2.21 µM (n = 3) was achieved with the proposed electrochemical sensor. The developed L-Cys sensor was also applied for L-Cys detection in various milk samples and acceptable recovery values were obtained ranging from 100.05 to 108.45%. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05866-1.

Electro-Nano Diagnostic Platform Based on Antibody-Antigen Interaction: An Electrochemical Immunosensor for Influenza A Virus Detection.

H1N1 is a kind of influenza A virus that causes serious health issues throughout the world. Its symptoms are more serious than seasonal flu and can sometimes be lethal. For this reason, rapid, accurate, and effective diagnostic tests are needed. In this study, an electrochemical immunosensor for the sensitive, selective, and practical detection of the H1N1 virus was developed. The sensor platform included multi-walled carbon nanotube gold-platinum (MWCNT-Au-Pt) hybrid nanomaterial and anti-hemagglutinin (anti-H1) monoclonal antibody. For the construction of this biosensor, a gold screen-printed electrode (AuSPE) was used as a transducer. Firstly, AuSPE was modified with MWCNT-Au-Pt hybrid nanomaterial via drop casting. Anti-H1 antibody was immobilized onto the electrode surface after the modification process with cysteamine was applied. Then, the effect of the interaction time with cysteamine for surface modification was investigated. Following that, the experimental parameters, such as the amount of hybrid nanomaterial and the concentration of anti-H1 were optimized. Under the optimized conditions, the analytical characteristics of the developed electrochemical immunosensor were investigated for the H1N1 virus by using electrochemical impedance spectroscopy. As a result, a linear range was obtained between 2.5-25.0 µg/mL with a limit of the detection value of 3.54 µg/mL. The relative standard deviation value for 20 µg/mL of the H1N1 virus was also calculated and found as 0.45% (n = 3). In order to determine the selectivity of the developed anti-H1-based electrochemical influenza A immunosensor, the response of this system towards the H3N2 virus was investigated. The matrix effect was also investigated by using synthetic saliva supplemented with H1N1 virus.

Oxidase mimicking Co/2Fe MOF included biosensor for sialic acid detection.

A facile amperometric biosensor that included oxidase mimicking Co/2Fe metal-organic framework (MOF) for sialic acid (SA) detection was prepared. Amperometric SA biosensor was constructed on a gold screen-printed electrode via immobilization of Co/2Fe MOF and N-acetylneuraminic Acid Aldolase (NANA-Aldolase) enzyme, respectively. NANA-Aldolase enzyme converts free SA into pyruvate and N-acetyl-d-mannosamine. After this conversion, oxidase mimicking Co/2Fe bimetallic MOF converts pyruvate into acetylphosphate and O2 into H2O2. Investigation of analytical characteristics resulted with the linear range of 0.02 mM-1.00 mM of SA concentration with limit of detection value of 0.026 mM. Sample application studies with developed SA biosensor were carried out with GD3 ganglioside and HeLa cancer cell lines which have high SA concentrations while A549 cell lines were also used as control group. Before detecting free SA, the bound SA was freed from SA sources where every step was monitored via electron impedance spectroscopy. Then, free SA was successfully detected with the amperometric SA biosensor and as a result, more practical and accurate system was developed.

An impedimetric approach for COVID-19 detection.

In this study, an electrochemical approach for the determination of coronavirus disease (COVID-19) was developed. The biosensor system relied on the spike protein (S-protein) based infection mechanism of the virus and included separate interactions of receptors like angiotensin-converting enzyme 2 (ACE2) and CD147. After the optimization of experimental parameters, the analytical characteristics of both receptors ACE2 and CD147 were investigated. For ACE2 receptor, the linear detection ranges of the S-protein were found in the range of 700 ng mL-1 to 1500 ng mL-1 and from 1500 ng mL-1 to 7000 ng mL-1 with a limit of detection (LOD) value of 299.30 ng mL-1. Meanwhile, for CD147 receptor the linear range was in the range of 500 ng mL-1 to 5000 ng mL-1 with a LOD value of 38.99 ng mL-1. After the examination of analytical characteristics, the developed electrochemical approach was applied for severe acute respiratory syndrome coronavirus 2 samples and the obtained results were validated with real time polymerase chain reaction method.

Development and application of a SARS-CoV-2 colorimetric biosensor based on the peroxidase-mimic activity of γ-Fe2O3 nanoparticles.

A practical colorimetric assay was developed for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For this purpose, magnetic γ Fe2O3 nanoparticles were synthesized and used as a peroxidase-like mimic activity molecule. In the presence of γ Fe2O3 nanoparticles, the color change of H2O2 included 3,3',5,5'-tetramethylbenzidine was monitored at the wavelength of 654 nm when spike protein interacted with angiotensin-converting enzyme 2 receptor. This oxidation-reduction reaction was examined both spectroscopically and by using electrochemical techniques. The experimental parameters were optimized and the analytical characteristics investigated. The developed assay was applied to real SARS-CoV-2 samples, and very good results that were in accordance with the real time polymerase chain reaction were obtained.

Development of a Sandwich Immunosensor for concurrent detection of carcinoembryonic antigen (CEA), vascular endothelial growth factor (VEGF) and α-fetoprotein (AFP) biomarkers.

Cancer Biomarkers are important biological molecules which provide early detection, diagnosis and classification of cancer cells. In this work, nanoparticle tags with different redox potentials have been used as an electrochemical coding technology for the simultaneous detection of carcinoembryonic antigen (CEA), vascular endothelial growth factor (VEGF) and α-fetoprotein (AFP) biomarkers. As far as we know, this is the only work that covers the simultaneous detections of these biomarkers. For this purpose, basically, an electrochemical sandwich immunosensor, which was fabricated from carbon screen printed electrode, was utilized as a diagnostic platform. As nanoparticle tags, PbAu@É£Fe2O3, CuAu@É£Fe2O3 and ZnAu@É£Fe2O3 hybrid nanolabels were synthesized and used for labelling anti-CEA, anti-VEGF and anti-AFP, respectively. By monitoring differential pulse voltammetric oxidation peaks of labeling metals (Pb, Cu, Zn), CEA, VEGF and AFP biomarkers were detected at the same time.

Metal organic frameworks in electrochemical and optical sensing platforms: a review.

Metal-organic frameworks (MOFs) are porous coordination polymers (CP) produced by metal-based nodes and multitopic organic ligands. Based on their porous and microcrystalline powder structures, they have initially been used for storage, catalysis and separation. Then, because of their advantageous properties like ease of the tailoring, they also have been applied in areas like chemical sensing, biological applications, etc. The CPs were combined with molecules such as organic dyes, small biomolecules, nanomaterials like nanoparticles, nanowires, nanofibers and polymers and as a result, composite MOFs have been produced. By this way, better mechanical stability, conductivity, and catalytic performance were obtained. This review (with 135 refs.) summarizes the progress made in the past years in the field of electrochemical and optical sensing based on the use of MOFs. Following an introduction into the field, large sections cover MOF based sensors exploiting (a) carbon nanomaterials (with subsections on carbon nanotubes, graphene and its derivatives), (b) metal/metal oxide MOFs; including gold, silver, copper and/or copper oxide nanoparticle and other metal/MOF composites. Enzyme mimicking MOFs are discussed next. In this context, after the brief information about focused MOFs, the nanomaterial/MOF composites were discussed and related examples were presented. Graphical abstract MOF structures in Sensing Systems.

Electrochemical detection of influenza virus H9N2 based on both immunomagnetic extraction and gold catalysis using an immobilization-free screen printed carbon microelectrode.

Influenza is a viral infectious disease considered as a source of many health problems and enormous socioeconomic disruptions. Conventional methods are inadequate for in-field detection of the virus and generally suffer from being laborious and time-consuming. Thus, studies aiming to develop effective alternatives to conventional methods are urgently needed. In this work, we developed an approach for the isolation and detection of influenza A virus subtype H9N2. For this aim, two specific influenza receptors were used. The first, anti-matrix protein 2 (M2) antibody, was attached to iron magnetic nanoparticles (MNPs) and used for the isolation of the virus from allantoic fluid. The second biomolecule, Fetuin A, was attached to an electrochemical detectable label, gold nanoparticles (AuNPs), and used to detect the virus tacking advantage from fetuin-hemagglutinin interaction. The MNP-Influenza virus-AuNP formed complex was isolated and treated by an acid solution then the collected gold nanoparticles were deposited onto a screen printed carbon electrode. AuNPs catalyzes the hydrogen ions reduction in acidic medium while applying an appropriate potential, and the generated current signal was proportional to the virus titer. This approach allows the rapid detection of influenza virus A/H9N2 at a less than 16 HAU titer.

Towards the electrochemical diagnostic of influenza virus: development of a graphene-Au hybrid nanocomposite modified influenza virus biosensor based on neuraminidase activity.

An effective electrochemical influenza A biosensor based on a graphene-gold (Au) hybrid nanocomposite modified Au-screen printed electrode has been developed. The working principle of the developed biosensor relies on the measurement of neuraminidase (N) activity. After the optimization of experimental parameters like the effect of bovine serum albumin addition and immobilization times of fetuin A and PNA lectin, the analytical characteristics of the influenza A biosensor were investigated. As a result, a linear range between 10-8 U mL-1 and 10-1 U mL-1 was found with a relative standard deviation value of 3.23% (for 10-5 U mL-1 of N, n:3) and a limit of detection value of 10-8 U mL-1 N. The developed biosensor was applied for real influenza virus A (H9N2) detection and very successful results were obtained.

Fabrication of Electrochemical Model Influenza A Virus Biosensor Based on the Measurements of Neuroaminidase Enzyme Activity.

Neuroaminidase (NA) enzyme is a kind of glycoprotein that is found on the influenza A virus. During infection, NA is important for the release of influenza virions from the host cell surface together with viral aggregates. It may also be involved in targeting the virus to respiratory epithelial cells. In this study, a model electrochemical influenza A viral biosensor in which receptor-binding properties have been based on NA was developed for the first time. The biosensor's working principle is based on monitoring the interactions between fetuin A and NA enzyme. The assay was monitored step by step by using electrochemical impedance spectroscopy.

An effective electrochemical biosensing platform for the detection of reduced glutathione.

A biosensor was developed using glutathione peroxidase (GSH-Px) as the enzyme. Firstly, platinum (Pt) nanoparticles were deposited onto a glassy carbon paste electrode (GCPE), and then GSH-Px was immobilized by means of gelatin that was then crosslinked with glutaraldehyde. The measurement was based on the electrochemical oxidation of GSH to its disulfide form in the presence of hydrogen peroxide. The linear range was found to be between 10 and 250 µM, with a correlation coefficient of R(2) = 0.9968. The R.S.D value for 25 µM GSH (n = 6) was calculated as 2.92%. Finally, the proposed biosensor was used to analyze GSH in a synthetically prepared plasma sample, and a promising recovery value was obtained.

Gr-Pt hybrid NP modified GCPE as label and indicator free electrochemical genosensor platform.

Glassy carbon paste electrode (GCPE) was modified with graphene platinum hybrid nanoparticle (Gr-Pt hybrid NP) and used as a transducer for label and indicator free electrochemical genosensor. 22 mer oligonucleotides representing Escherichia coli bacteria were used as a model case. As far as it is known, this study is the first study where Gr-Pt hybrid NP was incorporated into GCPE and used for genosensor transducer. The extent of hybridization was determined by using differential pulse voltammetric signals of guanin oxidation. After the optimization of experimental parameters, analytical characteristics were investigated. The linear range was found between 1.5×10(-7) and 2.25×10(-6) M with the equation of y=1.6566x-2.6161 and R(2) of 0.9959. RSD and LOD were calculated as 4.2% (n=6) and 1.12×10(-9) M respectively.

Nanomaterial-based composite biosensor for glucose detection in alcoholic beverages.

A composite electrode was prepared by modifying glassy carbon micro particles with gold nanoparticles and glucose oxidase enzyme for glucose detection. In terms of analytical characteristics, a linearity was obtained in the concentration range between 50.0 and 1000.0 µM with equation of y = 0.0015x + 0.2336 with the correlation coefficient of R(2) = 0.9801. R.S.D. value was calculated for 400 µM glucose (n = 6) and found to be 4.89%. LOD and LOQ values were also calculated and revealed to be 52.9 µM and 176.3 µM, respectively. The developed system was also applied for detection of glucose in four types of alcoholic beverages.

Effect of Nitric Acid "Washing" Procedure on Electrochemical Behavior of Carbon Nanotubes and Glassy Carbon µ-Particles.

The electroanalytic performances of glassy carbon paste electrode (GCPE), multi-walled carbon nanotube (MWCNT)-GCPE and double-walled carbon nanotube (DWCNT)-GCPE, which include HNO3 washed/unwashed materials, were compared by monitoring cyclic voltammograms of potassium ferricyanide and catechol. Electrodes were prepared by introducing proper amount of DWCNT and MWCNT into GCPE. First untreated materials (DWCNT, MWCNT, GC µ-particles) were used in the electrodes and then HNO3-treated materials were utilized for comparing difference in electrochemical performances. The effect of treatment procedure was also examined by applying Raman spectroscopy to treated and untreated materials. Moreover, TEM images were obtained for further investigation of MWCNT and DWCNT.

Alpha-glucosidase based bismuth film electrode for inhibitor detection.

A biosensing system based on alpha-glucosidase (AG) activity was developed by using bismuth film modified glassy carbon electrode (BiFE). AG enzyme was immobilized on the BiFE by means of gelatin membrane and the activity was measured by the following of liberated 4-nitrophenol from the 4-nitrophenyl-alpha-D-glucopyranoside (PNPGP) which is the synthetic substrate of the enzyme at the working potential of -950 mV. The proposed system was used as an AG based biosensing system. Experimental data showed that the response current of 4-nitrophenol obtained at the BiFE was linear in concentration range between 0.033 and 0.33 mM of PNPGP. Before examining the analytical characteristics, pH optimization of the AG-biosensor was also performed. Furthermore, the proposed method was applied to analyze two different AG inhibitors (Amaryl and Acorbose) which are important in Noninsulin-dependent diabetes mellitus (NIDDM).

Examination of performance of glassy carbon paste electrode modified with gold nanoparticle and xanthine oxidase for xanthine and hypoxanthine detection.

A composite electrode was prepared by modifying glassy carbon microparticles with gold nanoparticles (Au-nps) and xanthine oxidase enzyme (XOD) for xanthine (X) and hypoxanthine (Hx) detection. After the optimization of the system for X, the biosensor was characterized for X and Hx. A linearity was obtained in the concentration range between 5.00 x 10(-7) and 1.00 x 10(-5) M for X with equation of y=0.24 x + 0.712 and 5.00 x 10(-6) to 1.50 x 10(-4) M for Hx, with equation of y = 0.014 x + 0.575, respectively. Obtained results were compared to X and/or Hx biosensors including/not including Au-np in the structure. The developed system was also applied for detection of Hx in canned tuna fish sample and very promising results were obtained.