Since influenza and COVID-19 cause similar symptoms, the need for selective, sensitive and practical systems for influenza A detection has been highlighted. For this reason, in this work, a graphene ...(Gr) based nanomaterial modified anti-hemagglutinine 3, from now on will be called Gr-antiH3, based disposible electrochemical influenza immunosensor was developed. In order to obtain the highest sensitivity, the effects of various Gr-based nanomaterials on developed electrochemical immunosensor responses were investigated. For this purpose, graphene oxide, Gr, Gr-platinum (Gr-Pt), Gr-gold and Gr-gold-platinum nanomaterials were synthesized and characterized via electrochemical impedance spectroscopy (EIS). As a result, since the best results were obtained with Gr-Pt, this nanomaterial was integrated into H3N2 immunosensor system as a modifier. The Gr-Pt modified immunosensor was shown to provide a linear range from 0.5 µg/mL to 7 µg/mL. The limit of detection was 0.38 µg/mL and limit of quantification was 1.28 µg/mL with a relative standard deviation of 3.05%. The developed biosensor was applied to H3N2 detection in synthetic saliva samples and promising results were obtained with recoveries of 100.41 ± 1.10%.
A practical colorimetric assay was developed for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For this purpose, magnetic γ Fe
2
O
3
nanoparticles were synthesized ...and used as a peroxidase-like mimic activity molecule. In the presence of γ Fe
2
O
3
nanoparticles, the color change of H
2
O
2
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.
Graphical abstract
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.
An impedimetric biosensor that was based on SARS-CoV-2 infection mechanism was developed.
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.
A practical and sensitive electrochemical sensor for hemoglobin (Hb) detection was developed. The main electrochemical reaction was the reduction of Fe (III) in the Hb structure. For the construction ...of the sensor, Hb was physically immobilized onto a carbon felt electrode (CFE) without using any linker or applying any pre-functioning or electrochemical procedures. After examining the electrochemical mechanism, the experimental conditions, such as pH, were optimized and the analytical characteristics were investigated. A linear range of 0.05 µM to 3.00 µM with a detection limit of 4.4 nM was obtained for Hb. The relative standard deviation value for 3 replicate determinations of 0.05 µM Hb was calculated as1.35%. The developed sensor was successfully applied for Hb detection via standard addition method in synthetic physiological serum sample. Meanwhile, the influences of interfering reagents, such as cysteine, ascorbic acid, bovine serum albumin, and glucose, on Hb detection were also examined.
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% (
= 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.
In this study, gold nanoparticle (AuNP)-modified carbon paste electrode (CPE)-based electrochemical sensor for hyaluronic acid (HA) detection was developed. The change in the electrode surface area ...and the increase in HA electrochemical signals after modification with AuNP were investigated. Afterwards, pH and scan rate effects on developed HA sensor response were extensively studied and analytical characteristics were examined. As a result, limit of detection and limit of quantification values of developed sensor were found as 0.0034 mg/100 mL HA and 0.0115 mg/100 mL HA, respectively. Meanwhile, reproducibility and relative standard deviation values for 0.08 mg/100 mL HA were also calculated and found as 2.04% (
n
= 3). For the interference study, ascorbic acid, glucose, acetylcholine and H
2
O
2
were chosen as interfering substances, and in the presence of cocktail of these molecules, the recovery values were estimated as 102.79% (onefold) 97.88% (twofold) and 100.30% (threefold). Also, AuNP/CPE sensor was applied for HA detection in dermatological HA serum, sheet mask and hair serum. Acceptable recovery values varying between 99.86 and 100.70% were obtained with real samples, which shows the applicability of the developed sensor.
An electrochemical biosensor that monitored neuraminidase (NEU3), activity was developed. The analysis platform included a graphene‐platinum hybrid modified gold screen printed electrode as a ...transducer. The detection protocol was based on observation of NEU3 activity which was used to remove sialic acid from the GD3 ganglioside. Examination of analytical characteristics resulted with two linear ranges of 10−8 U/mL–10−1 and 10−1 U/mL–2.53 U/mL with limit of detection values of 10−8 U/mL and 10−1 U/mL, respectively. The selectivity of the developed NEU3 activity based electrochemical biosensor was tested with HeLa, VERO and A549 cell lines.
A N,N’-Bis(1-isobutyl-1H-benzimidazole-2-yl)perylene- 3,4,9,10-tetracarboxylic acid diimide (H1) modified carbon felt electrode has been prepared and applied for dopamine detection. Dopamine was ...chosen as the test analyte considering the negative charge density of H1 and positive charge of dopamine at this pH. The experimental conditions were optimized, and as analytical characteristic the linear range was found between 1 and 100 µM with an equation of
y
= 0.2149
x
+ 0.6928,
R
2
:0.998. Apart from that, the limit of detection, limit of quantification, and relative standard deviation values were calculated as 0.93 µM, 3.11 µM, and 4.56% for 50 µM of dopamine (
n
= 3), respectively. After the interference effects of catechol and ascorbic acid were examined, the developed sensor was applied for dopamine detection in medicinal ampoules.
Graphical abstract
A biofuel cell (BFC) was fabricated by combining multiwalled carbon nanotube ‐platinum‐gold (MWCNT−Pt−Au) hybrid nanomaterial, glucose oxidase (GOx) and benzoquinone included carbon felt electrode ...(CFE) bioanode with apple tissue included CFE biocathode. The working parameters of bioanode were optimized both experimentally and chemometrically. For the biocathode, apple, banana and pear tissues were tried and best power output was obtained with apple tissue. By combining MWCNT−Pt−Au/GOx/CFE bioanode with apple tissue based biocathode, single cell, double cell with membrane and with salt‐bridge BFCs were formed. The best power output with highest current density were obtained with single cell BFC.
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