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
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.
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.
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.
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•An amperometric sialic acid (SA) biosensor based on oxidase mimicking Co/2Fe metal-MOF was prepared.•The biosensor included Co/2Fe MOF and NANA-Aldolase enzyme immobilized on AuSPE.•MOF converts pyruvate into acetylphosphate and oxygen into H2O2.•With developed biosensor, free SA was successfully detected.•Before detection of free SA, bound SA was released.
•Electrochemical caffeine detection using AuNP-GCPE was performed for the first time.•An effective and practical sensor was fabricated for the caffeine detection.•AuNP-GCPE exhibited good ...electrocatalytic activity to the caffeine oxidation.•Caffeine amount in cola samples was determined by using AuNP-GCPE and UV–Vis.•Compared to UV–Vis, more precise results were obtained with proposed method.
In the present study, simple and sensitive voltammetric determination of caffeine was carried out by using a gold nanoparticle-glassy carbon paste composite electrode (AuNP-GCPE) in 3.2mM H2SO4 (pH 2.5). The effects of supporting electrolyte, pH and AuNP amount on caffeine peak current were investigated. After the optimization of experimental parameters, analytical characteristics of AuNP-GCPE were examined and two linear ranges were obtained between 25–150μM and 200–1000μM with limit of detection values of 0.96μM and 4.90μM, respectively. Relative standard deviation for 50μM caffeine was also calculated as 7.52% (n=3). In order to evaluate the analytical performance of AuNP-GCPE, caffeine contents of various brands of cola samples were measured and compared with the results obtained by UV–Vis spectrometer. The obtained results by using the proposed composite electrode are in accordance with the caffeine contents that manufacturers claimed compared to UV–Vis. This composite electrode which utilizes the catalytic effect of AuNP with the simple preparation of GCPE, offers a fast and sensitive determination of caffeine in beverages as a practical application.
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.
H3N2, known as “swine flu” is a kind of influenza A virus that can also infect humans. Therefore, rapid, practical and accurate techniques for H3N2 detection is needed. In this study, we fabricate ...Graphene‐gold hybrid nanomaterial modified hemagglutinin‐3 antibody (anti‐H3) based electrochemical immunosensor for practical, sensitive, and selective detection of H3N2 virus. The specific interaction between anti‐H3 and H3 protein on H3N2 virus was monitored with electrochemical impedance spectroscopy. After experimental parameters were optimized, analytical characteristics were searched. A linearity in the range of 1.0–17.5 μg/mL with limit of detection value of 1.01 μg/mL were obtained for the virus. Relative standard deviation value was found as 4.60 % for 15 μg/mL H3N2 virus (n=3). By using synthetic saliva solution that was supplemented with the virus, matrix effect was also investigated. Lastly, the selectivity of developed anti‐H3 based electrochemical influenza A immunosensor was investigated by applying it for H1N1 virus detection.
Anti‐H3 antibody based Graphene‐Au hybrid nanomaterial modified immunosensor was developed for the effective, practical and economic detection of H3N2 virus which was selected as model influenza A virus. This developed platform has a potential application to diagnose different types of influenza viruses that contain the H3 protein on their surfaces.
The attractive features of nanomaterials enable them to be used in a variety of areas including drug delivery (DD) systems. The advantages like better targeting and effective delivery, promote the ...usage of these materials in the structure of DD. However, the hazardous effects of nanomaterials must be considered before allowing them to be utilized in vivo. Because of their metallic based natures and small dimensions, nanomaterials can be toxic to human beings. Therefore the cons and pros of the usage of nanomaterials in DD systems must be extensively considered. In this review, after the brief history of DD systems and the usage of nanomaterials in these systems were presented, the selected nanomaterials cons and pros towards DD were examined. In conclusions and feature perspective part, the inadequacy of numbers of in-vivo studies was discussed and the need for more in-vivo tests was emphasized.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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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