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Bisphenols threaten human health and sensitive detection is crucial. The present study aims to develop ternary composites of copper metal-organic framework (Cu-MOF) with AuAg microstructures. The composite structure was formed by a galvanic displacement reaction and confirmed using SEM. A binder-free catalyst was used to study the electrochemical redox reaction of bisphenol A (BPA) and bisphenol S (BPS); an irreversible cyclic voltammetric signal at +0.70 V and + 0.91 V (vs. Ag/AgCl), in the dynamic range of 20 nM to 2.0 mM, and 10 nM to 1.0 mM, with limits of detection of 2.9 nM, and 3.2 nM (S/N = 3) was obtained. Practical analysis was applied to frozen tomatoes, tuna fish, milk powder, PET bottles, raw milk, and urine samples with a recovery rate of 94.00-100.80% (n = 3). Voltammetric results were validated using HPLC detection with high precision. The sensor is a promising alternative platform for measuring BPA in food samples.
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Compuestos de Bencidrilo , Técnicas Electroquímicas , Contaminación de Alimentos , Estructuras Metalorgánicas , Leche , Fenoles , Solanum lycopersicum , Fenoles/química , Fenoles/análisis , Compuestos de Bencidrilo/análisis , Compuestos de Bencidrilo/química , Contaminación de Alimentos/análisis , Técnicas Electroquímicas/instrumentación , Solanum lycopersicum/química , Estructuras Metalorgánicas/química , Leche/química , Animales , Límite de Detección , Cobre/química , Cobre/análisis , Sulfonas/química , Oro/química , AtúnRESUMEN
Developing quantitative biosensors of superoxide (O2â¢-) and nitric oxide (NO) anion is crucial for pathological research. As of today, the main challenge for electrochemical detection is to develop high-selectivity nano-mimetic materials to replace natural enzymes. In this study, the dendritic-like morphological structure of silver organic framework (Ag-MOF) was successfully synthesized via a solvothermal strategy. Owing to the introduction of polymeric composites results in improved electrical conductivity and catalytic activity, which promotes mass transfer and leads to faster electron efficiency. For monitoring the electrochemical signals of O2â¢- and NO, the Ag-MOF electrode substrate was produced by drop-coating, and composites were designed by cyclic voltammetric potential cycles. The designed electrode substrates demonstrate high sensitivity, wide linear concentrations of 1 nM-1000 µM and 1 nM-850 µM, and low detection limits of 0.27 nM and 0.34 nM (S/N = 3) against O2â¢- and NO. Aside from that, the sensor successfully monitored the cellular release of O2â¢-, and NO from HepG2 and RAW 264.7 living cells and has the potential to monitor exogenous NO release from donors of Diethylamine (DEA)-NONOate and sodium nitroprusside (SNP). Additionally, the developed system was applied to the analysis of O2â¢- and NO in real biological fluid samples, and the results were good satisfactory (94.10-99.57 ± 1.23%). The designed system provides a novel approach to obtaining a good electrochemical biosensor platform that is highly selective, stable, and flexible. Finally, the proposed method provides a quantitative way to follow the dynamic changes in O2â¢- and NO in biological systems.
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Técnicas Biosensibles , Técnicas Electroquímicas , Óxido Nítrico , Superóxidos , Técnicas Biosensibles/métodos , Óxido Nítrico/análisis , Óxido Nítrico/química , Humanos , Superóxidos/análisis , Superóxidos/química , Técnicas Electroquímicas/métodos , Ratones , Animales , Células Hep G2 , Células RAW 264.7 , Catálisis , Límite de Detección , Estructuras Metalorgánicas/química , Plata/química , Biomarcadores/análisis , Donantes de Óxido Nítrico/químicaRESUMEN
The development of artificial receptors has great significance in measurement science and technology. The need for a robust version of natural receptors is getting increased attention because the cost of natural receptors is still high along with storage difficulties. Aptamers, imprinted polymers, and nanozymes are some of the matured artificial receptors in analytical chemistry. Recently, a new direction has been discovered by organic chemists, who can synthesize robust, activity-based, self-immolative organic molecules that have artificial receptor properties for the targeted analytes. Specifically designed trigger moieties implant selectivity and sensitivity. These latent electrochemical redox substrates are highly stable, mass-producible, inexpensive, and eco-friendly. Combining redox substrates with the merits of electrochemical techniques is a good opportunity to establish a new direction in artificial receptors. This Review provides an overview of electrochemical redox substrate design, anatomy, benefits, and biosensing potential. A proper understanding of molecular design can lead to the development of a library of novel self-immolative redox molecules that would have huge implications for measurement science and technology.
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γ-Glutamyl transpeptidase (GGT) is a key biomarker for cancer diagnosis and post-treatment surveillance. Currently available methods for sensing GGT show high potential, but face certain challenges including an inability to be used to directly sense analytes in turbid biofluid samples such as whole blood without tedious sample pretreatment. To overcome this issue, activity-based electrochemical probes (GTLP and GTLPOH) were herein developed for a convenient and specific direct targeting of GGT activity in turbid biosamples. Both probes were designed to have GGT catalyze the hydrolysis of the gamma-glutamyl amide moiety of the probe, and result in a self-immolative reaction and concomitant ejection of the masked amino ferrocene reporter. The GTLPOH probe, delivered distinctive key results including high sensitivity, high affinity, a wide detection range of 2-100 U/L, and low LOD of 0.38 U/L against GGT. This probe delivered a precise target for sensing GGT and was free of interference from other electroactive biological species. Furthermore, the GTLPOH probe was employed to monitor and quantify the activity of GGT on the surfaces of tumor cells. The designed sensing method was also validated by the direct quantitative measurement of GGT activity in whole blood and urine samples, and the results were found to be consistent with those of the standard fluorometric assay kit. Thus, GTLPOH is of great significance for its promise as a point-of-care tool for early-stage cancer diagnosis as well as a new drug screening method.
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Técnicas Biosensibles , Neoplasias , Humanos , gamma-Glutamiltransferasa , Biomarcadores de Tumor , Técnicas Biosensibles/métodos , Amidas , Neoplasias/diagnósticoRESUMEN
Tannic acid (TA) is a water-soluble polyphenol and used in beverages, medical fields as clarifying and additive agents. In daily life, TA is unavoidable, and excessive consumption of tannin containing foods can harm health. Thus, rapid and sensitive quantification is highly necessary. Herein, an eco-friendly fluorometric and electrochemical sensing of TA was developed based on a dysprosium(III)-metal-organic framework (Dy(III)-MOF). An aqueous dispersion of Dy(III)-MOF exhibits strong dual emissions at 479 and 572 nm with an excitation at 272 nm, due to the 4f-4f electronic transition and "antenna effect". Chromophore site of the functional ligand, and Dy(III) ion could potentially serve as a sensing probe for TA via quenching (fluorescence). The fluorometric sensor worked well in a wide linear range concentrations from 0.02 to 25 µM with a limit of detection (LOD) of 0.0053 µM. Secondly, the cyclic voltammetric of TA at Dy(III)-MOF modified screen-printed carbon electrode (SPCE) has been investigated. The Dy(III)-MOF/SPCE showed an anodic peak signal at +0.22 V with a five-fold stronger current than the control electrode surface. Under optimized sensing parameters, the Dy(III)-MOF/SPCE delivered wide linear concentrations from 0.01 to 200 µM with a LOD of 0.0023 µM (S/N = 3). Accessibility of real practical samples in alcoholic and juice-based beverages were quantified, resulting in superior recovery rates (98.13-99.53%), F-test, and t-test confirmed high reliability (<95% confidence level (n = 3)). Finally, practicability result of the electrochemical method was validated by fluorometric with a relative standard deviation (RSD) of 0.18-0.46 ± 0.17% (n = 3). The designed probe has proven to be a key candidate for the accurate analysis of TA in beverage samples to ensure food quality.
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Frutas , Agua , Reproducibilidad de los Resultados , Carbono , Colorantes Fluorescentes , Bebidas , TaninosRESUMEN
For clinical research, the precise measurement of hydrogen peroxide (H2O2) and glucose (Glu) is of paramount importance, due to their imbalanced concentrations in blood glucose, and reactive oxygen species (ROS) play a huge role in COVID-19 viral disease. It is critical to construct and develop a simple, rapid, flexible, long-term, and sensitive detection of H2O2 and glucose. In this paper, we have developed a unique morphological structure of MOF(Cu) on a single-walled carbon nanotube-modified gold wire (swnt@gw). Highly designed frameworks with nanotube composites enhance electron rate-transfer behavior while extending conductance and electroactive surface area.The composite sensing system delivers wide linear-range concentrations, low detection limit, and interference-free performance in co-existence with other biomolecules and metal ions. Endogenous quantitative tracking of H2O2 was performed in macrophage live-cells with the help of a strong stimulator lipopolysaccharide.The composite device was effectively utilized for the measurement of H2O2 and glucose in turbid samples of whole blood and milk samples without a pretreatment process. The practical results of biofluids showed favorable voltammetric results and acceptance recovery percentage levels between 97.49 and 98.88%. Finally, a flexible MOF-based hybrid system may provide a suitable detection platform in the construction of electro-biosensors and hold potential promise for clinical-sensory applications.
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Técnicas Biosensibles , COVID-19 , Humanos , Cobre/química , Oro/química , Peróxido de Hidrógeno/química , Glucosa , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Límite de DetecciónRESUMEN
Nanomaterials frequently draw a lot of interest in a variety of disciplines, including electrochemistry. Developing a reliable electrode modifier for the selective electrochemical detection of the analgesic bioflavonoid i.e., Rutinoside (RS) is a great challenge. Here in, we have explored the supercritical-CO2 (SC-CO2) mediated synthesis of bismuth oxysulfide (SC-BiOS) and reported it as a robust electrode modifier for the detection of RS. For a comparison study, the same preparation procedure was carried out in the conventional approach (C-BiS). The morphology, crystallography, optical, and elemental contribution analyses were characterized to understand the paradigm shift in the physicochemical properties between SC-BiOS and C-BiS. The results exposed the C-BiS had a nano-rod-like structure with a crystallite size of 11.57 nm; whereas the SC-BiOS had a nano-petal-like structure with a crystallite size of 9.03 nm. The B2g mode in the optical analysis confirms the formation of bismuth oxysulfide by the SC-CO2 method with the Pmnn space group. As an electrode modifier, the SC-BiOS achieved a higher effective surface area (0.074 cm2), higher electron transfer kinetics (0.13 cm s-1), and lower charge transfer resistance (403 Ω) than C-BiS. Further, it provided a wide linear range of 0.1-610.5 µM L-1 with a low detection and quantification limit of 9 and 30nM L-1 and an appreciable sensitivity of 0.706 µA µM-1 cm-2. The selectivity, repeatability, and real-time application towards the environmental water sample with a recovery of 98.87% were anticipated for the SC-BiOS. This SC-BiOS unlocks a fresh avenue to construct a design for the family of electrode modifiers utilized in electrochemical applications.
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Dióxido de Carbono , Nanotubos , Dióxido de Carbono/química , Bismuto , Transporte de Electrón , ElectrodosRESUMEN
A simple and rapid screening of biomarkers in clinical and food matrices is urgently needed to diagnose cardiovascular diseases. The cholesterol (Chol) and hydrogen peroxide (H2O2) are critical bio-indicators, which require more inventive detection techniques to be applied to real food, and bio-samples. In this study, a robust dual sensor was developed for Chol and H2O2 using hybrid catalyst. Bovine serum albumin (BSA)-capped nanocatalyst was potentially catalyzed 3,3',5,5'-tetramethylbenzidine (TMB), and H2O2. The enzymatic nanoelectrocatalyst delivered a wide range of signaling concentrations from 250 nM to 3.0 mM and 100 nM to 10 mM, limit of detection (LOD) of 53.2 nM and 18.4 nM for Chol and H2O2. The cholesterol oxidase-BSA-AuNPs-metal-free organic framework (ChOx-BSA-AuNPs-MFOF) based electrode surface effectively operated in live-cells and real-food samples. The enzymatic sensor exhibits adequate recovery of real-food samples (96.96-99.44%). Finally, the proposed system is a suitable choice for the potential applications of Chol and H2O2 in clinical and food chemistry.
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Técnicas Biosensibles , Nanopartículas del Metal , Nanocompuestos , Peróxido de Hidrógeno/química , Peroxidasa , Oro/química , Nanopartículas del Metal/química , Oxidorreductasas , Peroxidasas , Colorantes , Colesterol , Técnicas Biosensibles/métodos , Colorimetría/métodos , Límite de DetecciónRESUMEN
BACKGROUND: yqiC is required for colonizing the Salmonella enterica serovar Typhimurium (S. Typhimurium) in human cells; however, how yqiC regulates nontyphoidal Salmonella (NTS) genes to influence bacteria-host interactions remains unclear. METHODS: The global transcriptomes of S. Typhimurium yqiC-deleted mutant (ΔyqiC) and its wild-type strain SL1344 after 2 h of in vitro infection with Caco-2 cells were obtained through RNA sequencing to conduct comparisons and identify major yqiC-regulated genes, particularly those involved in Salmonella pathogenicity islands (SPIs), ubiquinone and menaquinone biosynthesis, electron transportation chains (ETCs), and carbohydrate/energy metabolism. A Seahorse XFp Analyzer and assays of NADH/NAD+ and H2O2 were used to compare oxygen consumption and extracellular acidification, glycolysis parameters, adenosine triphosphate (ATP) generation, NADH/NAD+ ratios, and H2O2 production between ΔyqiC and SL1344. RESULTS: After S. Typhimurium interacts with Caco-2 cells, yqiC represses gene upregulation in aspartate carbamoyl transferase, type 1 fimbriae, and iron-sulfur assembly, and it is required for expressing ilvB operon, flagellin, tdcABCD, and dmsAB. Furthermore, yqiC is required for expressing mainly SPI-1 genes and specific SPI-4, SPI-5, and SPI-6 genes; however, it diversely regulates SPI-2 and SPI-3 gene expression. yqiC significantly contributes to menD expression in menaquinone biosynthesis. A Kyoto Encyclopedia of Genes and Genomes analysis revealed the extensive association of yqiC with carbohydrate and energy metabolism. yqiC contributes to ATP generation, and the analyzer results demonstrate that yqiC is required for maintaining cellular respiration and metabolic potential under energy stress and for achieving glycolysis, glycolytic capacity, and glycolytic reserve. yqiC is also required for expressing ndh, cydA, nuoE, and sdhB but suppresses cyoC upregulation in the ETC of aerobically and anaerobically grown S. Typhimurium; priming with Caco-2 cells caused a reversed regulation of yiqC toward upregulation in these ETC complex genes. Furthermore, yqiC is required for maintaining NADH/NAD+ redox status and H2O2 production. CONCLUSIONS: Specific unreported genes that were considerably regulated by the colonization-associated gene yqiC in NTS were identified, and the key role and tentative mechanisms of yqiC in the extensive modulation of virulence factors, SPIs, ubiquinone and menaquinone biosynthesis, ETCs, glycolysis, and oxidative stress were discovered.
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Salmonella typhimurium , Transcriptoma , Humanos , Salmonella typhimurium/genética , NAD , Ubiquinona , Células CACO-2 , Peróxido de Hidrógeno/farmacología , Vitamina K 2 , Respiración de la Célula , Estrés Oxidativo/genética , Adenosina Trifosfato , CarbohidratosRESUMEN
Aminopeptidase N (APN/CD13) plays an important role in the growth and metastasis, of tumor, and is a potential biomarker for the post-treatment surveillance of cancer reoccurrence and progression of various malignancies. Thus, we have designed and prepared a convenient and ultrasensitive APN-targeting activity-based ratiometric electrochemical molecular substrate (Ala-AFC) for direct real-time monitoring of APN activity in biosamples. The APN in our experiment was used to hydrolyze the alanine moiety of the Ala-AFC probe and, as a result of this hydrolysis, realize concomitantly a cascade reaction to unmask the electrochemical reporter N-alkylated amino ferrocene (AAF). The Ala-AFC probe exhibited high sensitivity with a wide detection range of 0.05-110 ng mL-1 and a low limit of detection of 23.18 pg mL-1. The electrochemical signals were found to be distinctly specific for APN and free of interference from other electroactive biological species. Furthermore, the Ala-AFC probe was employed to monitor and quantify, in real-time, the activity of APN in tumor cells, whole blood, and urine. In addition, the results of our direct electrochemical quantifications of the amount of APN in whole blood and urine were found to be consistent with the results of the use of commercially available fluorometric assay kits to sense APN in serum and urine. Thus our approach shows promise as a point-of-care tool for cancer diagnostics and post-treatment surveillance of cancer reoccurrence.
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Técnicas Biosensibles , Líquidos Corporales , Neoplasias , Biomarcadores de Tumor , Antígenos CD13 , Humanos , Neoplasias/diagnósticoRESUMEN
Salmonella contamination is a major concern in food and public health safety, and carrying out episodic monitoring of Salmonella contamination in food and water bodies is essential for safeguarding public health and the economy. Therefore, there is an urgent need to develop an easy-to-operate Salmonella-targeting point-of-care detection platform. To this end, we designed two activity-based latent ratiometric electrochemical molecular substrates, denoted as Sal-CAF and Sal-NBAF, specifically for achieving easy, rapid, and selective profiling of Salmonella esterase (a Salmonella biomarker) under physiological conditions. The octyl esters of the substrates were cleaved by the esterase and triggered the trimethyl lock to eject the electron-rich aminoferrocene derivatives (CAF and NBAF), and the corresponding electrochemical signals were tracked at the negative region (-0.08 V vs Ag/AgCl) of the voltammetric spectrum. The Sal-CAF substrate was used to determine the concentration of Salmonella in a wide dynamic range (1.03 × 105-1.1 × 1010 CFU mL-1) with a low detection limit of 39.27 × 103 CFU mL-1. The developed probes were tested against various bacteria but were only activated by live Salmonella. Furthermore, the Sal-CAF probe was used directly in quantifying spiked live Salmonella spiked in milk samples and also used to effectively monitor and quantify Salmonella production in real-time. These achievements indicated the Sal-CAF probe to be a promising platform for point-of-care Salmonella analysis.
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Técnicas Biosensibles , SalmonellaRESUMEN
An efficient electrochemical biosensor has been developed for the simultaneous evaluation of DNA bases using AgNPs-embedded covalent organic framework (COF). The COF (p-Phenylenediamine and terephthalaldehyde) was synthesized by reflux (DMF; 150 °C; 12 h) and the nanoparticles were embedded from the aqueous solutions of AgNO3 and NaBH4. The nanocomposite-modified COF was confirmed by spectral, microscopic, and electrochemical techniques. The nanocomposite material was deposited on a glassy carbon electrode (GCE) and the redox behavior of AgNPs was confirmed by cyclic voltammetry. The electrocatalytic activities of DNA bases were analyzed by differential pulse voltammetry (DPV) in a physiological environment (PBS; pH = 7.0) based on simple and easy-to-use electrocatalyst. The AgNPs-COF/GCE showed well-defined anodic peak currents for the bases guanine (+ 0.63 V vs. Ag/AgCl), adenine (+ 0.89 V vs. Ag/AgCl), thymine (+ 1.10 V vs. Ag/AgCl), and cytosine (+ 1.26 V vs. Ag/AgCl) in a mixture as well as individuals with respect to the conventional, COF, and AgNPs/GCEs. The AgNPs-COF/GCE showed linear concentration range of DNA bases from 0.2-1000 µM (guanine; (G)), 0.1-500 µM (adenine (A)), 0.25-250 µM (thymine (T)) and 0.15-500 µM (cytosine (C)) and LOD of 0.043, 0.056, 0.062, and 0.051 µM (S/N = 3), respectively. The developed sensor showed reasonable selectivity, reproducibility (RSD = 1.53 ± 0.04%-2.58 ± 0.02% (n = 3)), and stability (RSD = 1.22 ± 0.06%-2.15 ± 0.04%; n = 3) over 5 days of storage) for DNA bases. Finally, AgNPs-COF/GCE was used for the determination of DNA bases in human blood serum, urine and saliva samples with good recoveries (98.60-99.11%, 97.80-99.21%, and 98.69-99.74%, respectively).
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Estructuras MetalorgánicasRESUMEN
Introducing ultrasound irradiation to the electrodeposition process can significantly improve the physical and chemical properties of deposited films. Meanwhile, the beneficial effects from supercritical-CO2, such as high diffusivity, high permeability, low surface tension, etc., would improve the electrodeposition process with better surface quality. In the shed of the light, the present work deals with the preparation of copper (Cu) films using the integrated techniques, i.e., ultrasonic-assisted supercritical-CO2 (US-SC-CO2) electrodeposition approach. For comparison, Cu films were also prepared by normal supercritical-CO2 (SC-CO2) and conventional electrodeposition methods. To investigate the characteristics of Cu films, surface morphology analysis, roughness analysis, X-ray diffraction studies (XRD), Linear polarization, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) were performed. In this work, EIS analysis was utilized for interfacial charge transfer resistance analysis with 5 mM [Fe(CN)6]-3/-4 redox system and corrosion analysis with 3.5 wt% NaCl solution. The observed results revealed that the film prepared with the US-SC-CO2 method have superior properties than those produced by normal SC-CO2 and conventional methods. Due to the combination of US-SC-CO2, the cavitation implosion occurs rapidly that enriches the deposited film quality, such as sufficient grain size, smoother surface, enhanced corrosion resistance, and charge carrier dynamics. On the other hand, the ultrasound effect with SC-CO2 helped to remove the weakly adhered metal ions on the electrode's surface.
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In this study, controlled growth of Ni-MOF was decorated in amino acid-functionalized graphene nanoplatelets (FxGnP) by a solvothermal approach. The synthesized nanocomposite was characterized by various spectral, microscopic, and electrochemical techniques. FE-SEM and TEM image results exhibited the sheet-like structure of FxGnP and spherical-like Ni-MOF with an average size of 5.6 µm. Appreciably, the size of Ni-MOF was reduced to â¼2.3 µm while introducing the FxGnP. The presence of a large number of hydroxyl and epoxy functional groups of FxGnP acts as a nucleation center and restricted the uncontrolled growth of Ni-MOF. The FxGnP-Ni-MOF composite was modified on GCE and then utilized for the oxidation of bisphenol A (BPA). The nanocomposite material showed a sharp peak at +0.38 V vs. Ag/AgCl (saturated NaCl) with a stable response for BPA due to their less particle size with high electroactive surface area and higher electrical conductance, whereas bare GCE failed to the stable determination of BPA. The developed assay for determination of BPA exhibited a wide linear range from 2 × 10-9 M to 10 × 10-6 M, LOD 0.184 × 10-9 M and sensitivity of 247.65 µA mM-1 cm-2. The FxGnP-Ni-MOF/GCE showed good stability and reproducibility against BPA. Finally, the present electrocatalyst was effectively utilized for the quantitative determination of BPA in water samples and obtained results were validated with HPLC method.
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The ultrasonic-assisted electrodeposition process significantly improves the mechanical and electrochemical properties. Meanwhile, supercritical fluid technology also enhances the electrodeposition process with increased benefits, such as low surface tension, permeability, high diffusivity, and density, which improves the surface quality through grain refinement. In this study, Zn-Co films were prepared using the ultrasonic-assisted supercritical-CO2 (US-SC-CO2) electrodeposition approach, and its pressure effect on the film was evaluated. The films were also prepared by the conventional and typical supercritical-CO2 (SC-CO2) methods for a comparison study. All the prepared films were characterized by morphological studies, elemental composition, crystal structure orientation, and microhardness tests. Later, the fabricated films were examined by potentiodynamic polarization technique and electrochemical impedance technique (EIS) with 3.5 wt.% NaCl solution for corrosion evaluation. Based on results, Zn-Co film prepared through the US-SC-CO2 process shows a spherical nodule like structure with reduced grain size and significantly enhanced hardness property. In XRD studies, the shift in diffracted peak's position reveals the increased proportion of Co ions. Further, EDX results also confirm the same with the characteristic peaks. Finally, compared to the other methods, the corrosion resistance was more efficient in the US-SC-CO2 process by 73.75%.
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Formaldehyde is a reactive carbonyl species (RCS) that is produced naturally in the human body via metabolic and epigenetic biochemical processes, yet in high concentrations is highly toxic to the environment as well as to living organisms. Therefore, we designed two ratiometric electrochemical molecular redox probes, Formaldehyde oxidative latent probe (FOLP) and dihydroxy-formaldehyde oxidative latent probe (HFOLP), for the selective profiling of endogenous formaldehyde. FOLP and HFOLP each underwent the aza-Cope reaction with formaldehyde followed by hydrolysis to eliminate unmask redox reporter N-alkylated aminoferrocene (AAF) to monitor their response current. The FOLP and HFOLP sensors showed broad dynamic ranges of 0.12-1000 µM and 0.09-3 mM for formaldehyde with detection limits of 48.2 nM and 31.6 µM, respectively. Also, since formaldehyde is the byproduct of biochemical reactions for detecting creatinine and creatinine is an important biomarker for chronic kidney disease (CKD), we tested the FOLP probe for its ability to monitor creatinine. It successfully did so, and this ability was used to develop an electrochemical platform for the quantification of creatinine; it showed a dynamic range of 3.25-200 µM and a limit of detection (1.3 µM). In addition, the FOLP-based assay platform delivered a reliable analytical performance for the quantification of formaldehyde in human whole blood and of creatinine in saliva, and also for the real-time monitoring of endogenous formaldehyde secretion in HeLa cells. Moreover, the concentrations determined using our method were found to be consistent with those determined using formaldehyde and creatinine fluorometric assay kits.
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Técnicas Biosensibles , Saliva , Creatinina , Formaldehído , Células HeLa , HumanosRESUMEN
A copper-1,4-naphthalenedicarboxylic acid-based organic framework (Cu-NDCA MOF) with different morphologies was synthesized by solvothermal synthetic route via a simple protonation-deprotonation approach. The synthesized Cu-NDCA MOFs were analyzed by diverse microscopic and spectral techniques. The FE-SEM and TEM image results exhibited the flake-like (FL), partial anisotropic (PAT), and anisotropic (AT)-Cu-NDCA MOFs formation obtained at different pH (3.0, 7.0, and 9.0) of the reaction medium. The AT-Cu-NDCA MOF/GC electrode not only increases the electroactive surface area but also boosts the electron transfer rate reaction compared to other modified electrodes (PAT- and FL-Cu-NDCA MOFs/GCEs). Under the optimized conditions, the modified electrode (AT-Cu-NDCA MOF) exhibited a sharp oxidation peak (+ 0.46 V vs. Ag/AgCl) and higher current response for rutin. The electrode provides a wide linear range from 1 × 10-9 to 50 × 10-6 M, a low detection limit of 1.21 × 10-10 M, LOQ of 0.001 µM, and sensitivity of 0.149 µA µM-1 cm-2. The AT-Cu-NDCA MOF/GC electrode exhibited good stability (RSD = 3.52 ± 0.02% over 8 days of storage), and excellent reproducibility (RSD = 2.62 ± 0.02% (n = 3)). The modified electrode was applied to the determination of rutin in apple, orange, and lemon samples with good recoveries (99.79-99.91, 99.24-99.69, and 99.53-99.83, respectively). Graphical abstract Anisotropic structure of Cu-NDCA MOFs and its modification on glassy carbon electrode for ultra-sensitive determination of rutin in fruit samples.
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Cobre/química , Técnicas Electroquímicas/métodos , Estructuras Metalorgánicas/química , Preparaciones Farmacéuticas/química , Tensoactivos/química , Catálisis , Límite de Detección , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Espectroscopía de Fotoelectrones , Protones , Reproducibilidad de los Resultados , Rutina/análisis , Difracción de Rayos XRESUMEN
There is an urgent need to develop in situ sensors that monitor the continued release of H2S from biological systems to understand H2S-related pathology and pharmacology. For this purpose, we have developed a molybdenum disulfide supported double-layered zinc cobaltite modified carbon cloth electrode (MoS2-ZnCo2O4-ZnCo2O4) based electrocatalytic sensor. The results of our study suggest that the MoS2-ZnCo2O4-ZnCo2O4 electrode has excellent electrocatalytic ability to oxidize H2S at physiological pH, in a minimized overpotential (+0.20 vs. Ag/AgCl) with an amplified current signal. MoS2 grown on double-layered ZnCo2O4 showed relatively better surface properties and electrochemical properties than MoS2 grown on single-layered ZnCo2O4. The sensor delivered excellent analytical parameters, such as low detection limit (5 nM), wide linear range (10 nM-1000 µM), appreciable stability (94.3%) and high selectivity (2.5-fold). The practicality of the method was tested in several major biological fluids. The electrode monitors the dynamics of bacterial H2S in real-time for up to 5 h with good cell viability. Our research shows that MoS2-ZnCo2O4-ZnCo2O4/carbon cloth is a robust and sensitive electrode to understand how bacteria seek to adjust their defense strategies under exogenously induced stress conditions.
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Disulfuros/química , Sulfuro de Hidrógeno/metabolismo , Molibdeno/química , Nanoestructuras/química , Compuestos de Zinc/química , Supervivencia Celular , Conductividad Eléctrica , Electroquímica , Escherichia coli/citología , Escherichia coli/metabolismo , Límite de Detección , Factores de TiempoRESUMEN
We report an optical biosensor using imine, 5-((anthrcene-9-ylmethylene) amino)-2,3dihydrophthalazine) 1-4-dione (ADD) for direct detection of ascorbic acid (AA) via FRET quenched. The ADD was successfully prepared by using simple ultra - sonication method, which was characterized by various spectroscopic techniques. The fluorescence intensity of ADD probe was drastically quenched in presence of AA, and shown excellent selectivity towards the detection of AA in presence of possible biological active interferences. A wide linear range from 0.25 to 190 µM was achieved towards the detection of AA with a LOD of 10 nM. The occurrence of FRET mechanism is due to intermolecular hydrogen bonding between ADD and AA, which was confirmed by Density Functional Theory calculations. Moreover, the biosensor was successfully applied for the detection of AA in real samples such as fruits and vegetables to demonstrate the practicability. In addition, the developed biosensor could be a simple and economically cheap platform for the detection of AA in food samples.
Asunto(s)
Ácido Ascórbico/análisis , Técnicas Biosensibles/métodos , Frutas/química , Luminol/análogos & derivados , Fenómenos Ópticos , Sonicación , Verduras/química , Técnicas de Química Sintética , Límite de Detección , Luminol/síntesis química , Luminol/químicaRESUMEN
Designing and engineering nanocomposites with tailored physiochemical properties through teaming distinct components is a straightforward strategy to yield multifunctional materials. Here, we describe a rapid, economical, and green one-pot microwave synthetic procedure for the preparation of ternary nanocomposites carbon/polydopamine/Au nanoparticles (C/PDA/AuNPs; C = carbon nanotubes (CNTs), reduced graphene oxide (rGO)). No harsh reaction conditions were used in the method, as are used in conventional hydrothermal or high-temperature methods. The PDA unit acts as a non-covalent functionalizing agent for carbon, through π stacking interactions, and also as a stabilizing agent for the formation of AuNPs. The CNTs/PDA/AuNPs modified electrode exhibited excellent electrocatalytic activity to oxidize chloramphenicol and the resulting sensor exhibited a low detection limit (36 nM), wide linear range (0.1-534 µM), good selectivity (against 5-fold excess levels of interferences), appreciable reproducibility (3.47%), good stability (94.7%), and practicality (recoveries 95.0%-98.4%). Likewise, rGO/PDA/AuNPs was used to fabricate a sensitive folic acid sensor, which exhibits excellent analytical parameters, including wide linear range (0.1-905 µM) and low detection limit (25 nM). The described synthetic route includes fast reaction time (5 min) and a readily available household microwave heating device, which has the potential to significantly contribute to the current state of the field.