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1.
Food Chem ; 441: 138381, 2024 May 30.
Article in English | MEDLINE | ID: mdl-38218150

ABSTRACT

The accumulation of the deoxynivalenol (DON) in the human body poses a significant health risk that is often overlooked, and we urgently need an ultra-sensitive rapid detection platform. Due to the porosity of NH2-MIL-101@MoS2, an increased loading of toluidine blue (TB) serves to create a signal reference. Cobalt@carbon (CoC) derived from metal organic frameworks was combined with NH2-MIL-101(NH2-MIL-101@CoC) to form an enzyme-free Nanoprobe (Apt-pro) with significant catalytic properties. The ratio (IBQ /ITB) was changed by varying the electrochemical signal of benzoquinone (BQ) (IBQ) and the amount of TB deposition (ITB). This aptasensor was successfully applied to detect DON in malt and peach seed, which exhibited a great linear range from 1 fg/mL to 10 ng/mL and low detection limit of 0.31 fg/mL for DON.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Metal Nanoparticles , Metal-Organic Frameworks , Trichothecenes , Humans , Metal-Organic Frameworks/chemistry , Peroxidase/chemistry , Molybdenum , Coloring Agents , Limit of Detection , Electrochemical Techniques , Aptamers, Nucleotide/chemistry , Metal Nanoparticles/chemistry
2.
Anal Chim Acta ; 1279: 341768, 2023 Oct 23.
Article in English | MEDLINE | ID: mdl-37827668

ABSTRACT

Cannabis is a plant that is harmful and beneficial because it contains more than 400 bioactive compounds, and the main compounds are Δ9 tetrahydrocannabinol (THC) and cannabidiol (CBD). Currently, cannabis extracts are used in medicine, but the amount of THC as a main psychoactive component is strictly regulated. Therefore, the ability to rapidly and accurately detect THC is important. Herein, we developed a sensitive electrochemical method combining a rapid lateral flow assay (LFA) to detect THC rapidly. An electrochemical LFA device was constructed by attaching a screen-printed electrode inside a lateral-flow device to exploit the remarkable binding of THC to the cannabinoid type 2 (CB2) receptor in the test zone. The ferrocene carboxylic acid attached to the monoclonal THC antibody acts as an electroactive species when it binds to the THC in the sample before it flows continuously to the CB2 receptor region on the electrode. Under optimal conditions, the detection time is within 6 min and the devise shows excellent performance with a detection limit of 1.30 ng/mL. Additionally, the device could be applied to detect THC in hemp extract samples. The results obtained from this sensor are similar to the standard method (HPLC) for detecting THC. Therefore, this proposed device is useful as an alternative device for the on-site determination of THC because it is inexpensive, portable, and exhibits high sensitivity.


Subject(s)
Cannabidiol , Cannabis , Dronabinol/analysis , Cannabis/chemistry , Cannabidiol/analysis , Cannabidiol/metabolism , Chromatography, High Pressure Liquid , Plant Extracts
3.
Mikrochim Acta ; 190(8): 281, 2023 07 05.
Article in English | MEDLINE | ID: mdl-37407849

ABSTRACT

A facile and novel Ce-MOF@MWCNTs@ZnO-modified glassy carbon electrode was prepared through drop coating and used for accurate and sensitive electrochemical detection of carbendazim. The modification of ZnO nanospheres and Ce-based metal-organic frameworks (Ce-MOFs), which possess vast surface/bulk ratio, large surface area, and excellent catalytic ability, provided more active sites for reaction. The combination of multi-walled carbon nanotubes endowed the modified electrode with excellent conductivity and greatly accelerated the electron transfer. The promotion of electrochemical response and the significant improvement of peak current indicated the outstanding electrocatalytic ability of the modified electrode. The oxidation peak current of carbendazim which was measured by DPV in a potential range from 0.5 to 1.0 V produced a good linear relationship in the concentration ranges 0.05-10.0 µM and 10.0-50.0 µM under  optimized experimental conditions. The detection limit was 13.2 nM (S/N = 3). The constructed electrode was successfully applied to the detection of carbendazim in Lithospermum and Glycyrrhiza uralensis real samples and exhibited satisfactory RSD (2.7-3.6% and 1.6-4.8%, respectively) and recovery (102-106% and 97.7-107%, respectively).


Subject(s)
Drugs, Chinese Herbal , Nanocomposites , Nanotubes, Carbon , Zinc Oxide , Electrochemical Techniques , Nanocomposites/chemistry , Nanotubes, Carbon/chemistry , Drugs, Chinese Herbal/analysis
4.
Anal Chim Acta ; 1272: 341522, 2023 Sep 01.
Article in English | MEDLINE | ID: mdl-37355338

ABSTRACT

The interesting adsorption affinity of two-dimensional nanosheets to single stranded over double stranded nucleic acids have stimulated the exploration of these materials in biosensing. Herein, MoS2 nanosheets decorated anodic aluminum oxide (AAO) membrane was simply prepared by suction filtration. The MoS2/AAO hybrid membrane was initially applied to the electrochemical detection of microRNA using let-7a as the model. When let-7a was incubated with its complementary DNA, double stranded DNA-RNA formed and which displayed weak adsorption capability to the hybrid membrane. And thus the steric effect combining the electrostatic repulsion of the backbone phosphate of nucleic acids for [Fe(CN)6]3- transport across the hybrid membrane varied with the concentration of let-7a. In this way, a label-free electrochemical detection method for microRNA was established by monitoring the change of the redox current of [Fe(CN)6]3-. To further improve the detection sensitivity of the method, we proposed two separate strategies focusing on the amplification of the target-induced steric hindrance with DNA nanostructure and the magnification of the electrode sensitivity for [Fe(CN)6]3- by electrode modification. By using the two strategies, the hybrid membrane based-detection method exhibited broad linear range, low detection limit and good selectivity as well as reproducibility. Therefore, this study provided a proof-of-concept for the application of two-dimensional material to nucleic acids detection.


Subject(s)
Biosensing Techniques , MicroRNAs , Aluminum Oxide/chemistry , Molybdenum/chemistry , Reproducibility of Results , Limit of Detection , DNA/chemistry , Electrodes , Electrochemical Techniques/methods , Biosensing Techniques/methods
5.
Anal Sci ; 39(4): 441-446, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36639558

ABSTRACT

In this study, the determination of oxalic acid in herbal medicines was performed by using a hydrophilic interaction liquid chromatography coupled with electrochemical detection (HILIC-ECD) method. A semi-micro column packed with amide-silica particles and an acetonitrile-30 mM phosphate buffer (pH 6.8) mixture (65:35, v/v) were used as the stationary and mobile phases, respectively, in the HILIC-ECD. A potential of + 1.1 V vs. Ag/AgCl was applied to a glassy carbon working electrode. The ratio of the peak height of oxalic acid to that of the internal standard (synephrine) was proportional to the concentration of 0.45 µg L-1 to 1.8 mg L-1 with a correlation coefficient of 0.999. The detection limit (signal-to-noise ratio, S/N = 3) of oxalic acid was 0.17 µg L-1. By the HILIC-ECD, the oxalic acid content in crude drugs and Kampo medicine extract granules (Zingiberis Rhizoma Processum, Pinelliae Tuber, Sho-seiryu-to, Hange-shashin-to, etc.) were determined with less than 2.9% relative standard deviation (RSD, n = 6), and their recoveries were more than 88.7% with less than 3.3% RSD (n = 6). In conclusion, we demonstrated that the HILIC-ECD performed measurements that were quite selective, accurate, and precise for the determination of oxalic acid in herbal medicines.


Subject(s)
Oxalic Acid , Plants, Medicinal , Chromatography, High Pressure Liquid/methods , Chromatography, Liquid/methods , Plant Extracts , Hydrophobic and Hydrophilic Interactions
6.
Methods Mol Biol ; 2565: 331-342, 2023.
Article in English | MEDLINE | ID: mdl-36205904

ABSTRACT

The determination of plasma catecholamine levels is commonly used as a measure of the sympathetic nervous system's response to stress and is highly important for diagnosis, therapy, and prognosis of cardiovascular diseases, catecholamine-secreting tumors arising from the chromaffin cells of the sympathoadrenal system, and affective disorders. Diseases in which catecholamines are significantly elevated include pheochromocytoma, Parkinson's disease, Alzheimer's disease, neuroblastoma, ganglioneuroblastoma, von Hippel-Lindau disease, baroreflex failure, chemodectina (nonchromaffin paraganglioma), and multiple endocrine neoplasia. Plasma norepinephrine levels provide a guide to prognosis in patients with stable, chronic, and congestive heart diseases. The method described here for the determination of plasma catecholamines is based on the principle that plasma catecholamines are selectively adsorbed on acid-washed alumina at pH 8.7 and then eluted at a pH between 1.0 and 2.0. Upon injection, catecholamines in elutes were separated by a reversed phase C-18 column. After separation, the catecholamines present within the mobile phase enter the electrochemical detector. Electrochemical detection occurs because electroactive compounds oxidize at a certain potential and thereby liberate electrons that create measurable current. Catecholamines readily form quinones under these conditions, get oxidized, release two electrons, and create current. The electrochemical detector detects this electrical current that linearly correlates to the catecholamine concentration loaded into the ultra-performance liquid chromatography instrument. A 15-min mixing time during the adsorption and desorption steps was found to be optimal. If the washing step was omitted, the catecholamines could not be eluted from the acid-washed alumina. To prevent dilution, the alumina had to be centrifuged and not aspirated to dryness after the washing step. We report here that by changing the range in the electrochemical detector, plasma catecholamines were measured with only 12.5 µL of plasma and more reliably with 25 µL of plasma. The detection limit was 1 ng/mL. This assay method is very useful as blood can be collected from the tail vein in a conscious mouse and the same mouse can be used for time-dependent or age-dependent studies.


Subject(s)
Adrenal Gland Neoplasms , Catecholamines , Aluminum Oxide , Animals , Chromatography, High Pressure Liquid/methods , Mice , Norepinephrine , Quinones , Tail
7.
Talanta ; 253: 123959, 2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36208556

ABSTRACT

Simultaneous selective determination of Fe (Ⅱ) and Fe (Ⅲ) is of great significance to the study of iron ion tracking and release of iron supplement in gastric fluid. In this paper, a composite material (N-CQDs/AgNPs/ß-CD) was prepared by a one-pot method. The various characterizations confirmed the silver nanoparticles (AgNPs) grew in situ on the surface of nitrogen-doped carbon quantum dots (N-CQDs), and the ß-cyclodextrin (ß-CD) and AgNPs linked together by Ag-O bonds finally presented gourd-like nanoparticles on the surface of N-CQDs. Then, N-CQDs/AgNPs/ß-CD modified glassy carbon electrode (GCE) was applied to detect Fe(II) and Fe(III) simultaneously. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results confirmed that N-CQDs/AgNPs/ß-CD enhanced electrode performances because of the synergistic effect between N-CQDs, AgNPs and ß-CD. The sensor was successfully applied for the determination by differential pulse voltammetry (DPV) of Fe(II) and Fe(III) released from four iron supplementations in simulated gastric fluid (SGF).


Subject(s)
Metal Nanoparticles , beta-Cyclodextrins , Carbon , Nitrogen , Ferric Compounds , Silver , Iron , Ferrous Compounds
8.
Biosens Bioelectron ; 222: 115003, 2023 Feb 15.
Article in English | MEDLINE | ID: mdl-36525711

ABSTRACT

Cancer spheroids, which mimic distinct cell-to-cell and cell-extracellular matrix interactions of solid tumors in vitro, have emerged as a promising tumor model for drug screening. However, owing to the unique characteristics of spheroids composed of three-dimensionally densely-packed cells, the precise characterizations of cell viability and function with conventional colorimetric assays are challenging. Herein, we report gold nanostructure-integrated conductive microwell arrays (GONIMA) that enable both highly efficient uniform cancer spheroid formation and precise electrochemical detection of cell viability. A nanostructured gold on indium tin oxide (ITO) substrate facilitated the initial cell aggregation and further 3D cell growth, while the non-cytophilic polymer microwell arrays restricted the size and shape of the spheroids. As a result, approximately 150 human glioblastoma spheroids were formed on a chip area of 1.13 cm2 with an average diameter of 224 µm and a size variation of only 5% (±11.36 µm). The high uniformity of cancer spheroids contributed to the stability of electrical signals measuring cell viability. Using the fabricated GONIMA, the effects of a representative chemotherapeutic agent, hydroxyurea, on the glioblastoma spheroids were precisely monitored under conditions of varying drug concentrations (0-0.3 mg/mL) and incubation times (24-48 h). Therefore, we conclude that the newly developed platform is highly useful for rapid and precise in vitro drug screening, as well as for the pharmacokinetic analyses of specific drugs using 3D cellular cancer models.


Subject(s)
Biosensing Techniques , Glioblastoma , Humans , Spheroids, Cellular , Drug Evaluation, Preclinical , Gold , Early Detection of Cancer
9.
Bioelectrochemistry ; 148: 108228, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35970121

ABSTRACT

A new electrode based on glassy carbon modified with a sulphur-doped graphene material was successfully developed and applied for caffeic acid (CA) voltammetric detection and quantification. The structural features of sulphur-doped graphene (exfGR-S) characterized by different physicochemical and analytical techniques are presented. Cyclic voltammetry (CV) technique was employed to evaluate the electrochemical behavior of both bare glassy carbon (GCE) and modified GCE/exfGr-S electrodes towards CA oxidation. The study revealed that the modified electrode exhibits superior electrochemical performances compared to the bare electrode, with a broad CA detecting range (from 0.1 to 100.0 µM), a low detection limit 3.03 × 10-8 M), excellent anti-interference capabilities, as well as good stability and repeatability. The developed electrochemical sensor appears to be a promising candidate for real sample quality control analysis since it successfully displayed its ability to directly detect CA in commercially available coffee product without any pretreatment.


Subject(s)
Graphite , Caffeic Acids , Carbon/chemistry , Coffee , Electrochemical Techniques , Graphite/chemistry , Sulfur
10.
Adv Sci (Weinh) ; 9(20): e2200074, 2022 07.
Article in English | MEDLINE | ID: mdl-35506260

ABSTRACT

Organoids that mimic the structural and cellular characteristics of kidneys in vitro have recently emerged as a promising source for biomedical research. However, uncontrollable cellular heterogeneity after differentiation often results in the generation of off-target cells, one of the most challenging issues in organoid research. This study proposes a new method that enables the real-time assessment of kidney organoids derived from stem cells. When placed on a conductive surface, these organoids generate unique electrochemical signals at ≈0.3 V with intensities proportional to the amount of kidney-specific cell types. Off-target cells (i.e., non-kidney cells) produce an electrical signature at 0 V that is distinguishable from other surrounding cell types, enabling non-destructive assessment of both the differentiation, and maturation levels of kidney organoids. The developed platform can be applied to other types of organoids and is thus highly promising as a tool for organoid-based drug screening, toxicity assessment, and therapeutics.


Subject(s)
Organoids , Pluripotent Stem Cells , Cell Differentiation , Drug Evaluation, Preclinical , Kidney
11.
Biosens Bioelectron ; 209: 114243, 2022 Aug 01.
Article in English | MEDLINE | ID: mdl-35421671

ABSTRACT

Chronic wounds represent an important healthcare challenge in developed countries, being wound infection a serious complication with significant impact on patients' life conditions. However, there is a lack of methods allowing an early diagnosis of infection and a right decision making for a correct treatment. In this context, we propose a novel methodology for the electrical monitoring of infection biomarkers in chronic wound exudates, using nanoporous alumina membranes. Lysozyme, an enzyme produced by the human immune system indicating wound infection, is selected as a model compound to prove the concept. Peptidoglycan, a component of the bacterial layer and the native substrate of lysozyme, is immobilized on the inner walls of the nanochannels, blocking them both sterically and electrostatically. The steric blocking is dependent on the pore size (20-100 nm) and the peptidoglycan concentration, whereas the electrostatic blocking depends on the pH. The proposed analytical method is based on the electrical monitoring of the steric/electrostatic nanochannels unblocking upon the specific degradation of peptidoglycan by lysozyme, allowing to detect the infection biomarker at 280 ng/mL levels, which are below those expected in wounds. The low protein adsorption rate and thus outstanding filtering properties of the nanoporous alumina membranes allowed us to discriminate wound exudates from patients with both sterile and infected ulcers without any sample pre-treatment usually indispensable in most diagnostic devices for analysis of physiological fluids. Although size and charge effects in nanochannels have been previously approached for biosensing purposes, as far as we know, the use of nanoporous membranes for monitoring enzymatic cleavage processes, leading to analytical systems for the specific detection of the enzymes has not been deeply explored so far. Compared with previously reported methods, our methodology presents the advantages of no need of neither bioreceptors (antibodies or aptamers) nor competitive assays, low matrix effects and quantitative and rapid analysis at the point-of-care, being also of potential application for the determination of other protease biomarkers.


Subject(s)
Biosensing Techniques , Wound Infection , Aluminum Oxide/chemistry , Biomarkers , Biosensing Techniques/methods , Humans , Muramidase , Peptidoglycan , Wound Infection/diagnosis
12.
J Sep Sci ; 45(10): 1797-1805, 2022 May.
Article in English | MEDLINE | ID: mdl-35247931

ABSTRACT

A supercritical fluid chromatography with electrochemical detection system was developed for the simultaneous determination of tocopherol and tocotrienol isomers. The supercritical fluid chromatography with electrochemical detection system was connected with an additional pump to create a flow path to add a supporting electrolyte solution. The supporting electrolyte solution was mixed with a mobile phase in a post-column fashion, enabling the independent control of the separation and detection. After optimization of the measurement conditions, vitamin E isomers and an internal standard substance (2,2,5,7,8-pentamethyl-6-hydroxychroman) were separated within 30 min using a mixture of supercritical carbon dioxide and methanol (99:1, v/v) as a mobile phase and a cyanopropyl column (4.6 mm inner diameter × 250 mm length, 5 µm). For the electrochemical detection, methanol containing 1.0 mol/L ammonium acetate was used as a supporting electrolyte solution, and the applied potential was set at +0.8 V. This analytical method showed good linearity (5-100 µg/mL) and repeatability (less than 2.5% relative standard deviation, n = 6) and was applicable to the determination of tocopherol and tocotrienol isomers in nutrition supplements.


Subject(s)
Chromatography, Supercritical Fluid , Tocotrienols , Chromatography, High Pressure Liquid/methods , Chromatography, Supercritical Fluid/methods , Electrolytes , Methanol , Tocopherols , Tocotrienols/analysis , Vitamin E/analysis
13.
J Sep Sci ; 44(20): 3777-3788, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34418299

ABSTRACT

A combinative method using high-performance liquid chromatography-electrochemical detection for fingerprinting and quantitative analysis was developed and successfully applied for the quality evaluation of Lophatherum gracile Brongn leaves collected from 21 geographical locations in China. In the fingerprint analysis, 18 common peaks were observed among the 21 samples, and 10 peaks were identified. Simultaneous quantification of the 10 components was conducted to interpret the variations in these compounds among the L. gracile Brongn leaves originating from different geographical locations. The correlation between the chromatograms and the antioxidant activities of the samples was further studied. The results indicated a linear correlation between the antioxidant activity and the total common peak areas of the fingerprints obtained by high-performance liquid chromatography-electrochemical detection. Importantly, it was found that high-performance liquid chromatography-electrochemical detection fingerprinting can not only determine the quantities of individual components present in such samples but also evaluate the antioxidant activities of the samples. The developed method is a valuable reference for the further study and development of L. gracile Brongn.


Subject(s)
Antioxidants/pharmacology , Drugs, Chinese Herbal/pharmacology , Electrochemical Techniques , Phytochemicals/pharmacology , Plant Extracts/pharmacology , Poaceae/chemistry , Antioxidants/analysis , Benzothiazoles/antagonists & inhibitors , Biphenyl Compounds/antagonists & inhibitors , Chromatography, High Pressure Liquid , Drugs, Chinese Herbal/analysis , Phytochemicals/analysis , Picrates/antagonists & inhibitors , Plant Extracts/analysis , Sulfonic Acids/antagonists & inhibitors
14.
Mikrochim Acta ; 188(6): 185, 2021 05 11.
Article in English | MEDLINE | ID: mdl-33977395

ABSTRACT

An abdominal aortic aneurysm (AAA) is abnormal swelling in the abdominal aorta and a prevalent life-threatening disease. This research introduces a new interdigitated microelectrode (IDME)-sensing surface modified by iron oxide nanoworms (IONWs) for detecting the AAA biomarker insulin-like growth factor-1 (IGF1). A sandwich pattern was formulated with the IGF1 aptamer and IGFBP1 (IGF binding protein-1) on the IONW-constructed IDME hybrid to identify IGF1. The surface morphology of the IONWs revealed a uniform distribution of worm-like structures (80-100 nm) as confirmed by FESEM and FETEM analyses. Further, the presence of the major elements, Fe and O, was confirmed by EDX and XPS studies. The crystal planes that appeared in the IONW reflect cubic magnetite. IONW-modified IDME attained a limit of detection for IGF1 of 1 fM (3σ) with an aptamer-IGF1-IGFBP1 sandwich. This sandwich with IGFBP1 enhanced the current level at all concentrations of IGF1 and displayed linearity in the range 1 fM to 100 pM with a determination coefficient of R2 = 0.9373 [y = 3.38221x - 4.79]. Control experiments with complementary aptamer sequences, IGF2 and IGFBP3 did not show notable signal changes, indicating the specific detection of IGF1. This IONW constructed electrode helps to achieve the detection of low amounts of IGF1 and diagnose AAA at the stage prior to rupture.


Subject(s)
Aortic Aneurysm, Abdominal/diagnosis , Insulin-Like Growth Factor I/analysis , Nanostructures/chemistry , Aortic Aneurysm, Abdominal/blood , Aptamers, Nucleotide/chemistry , Biomarkers/blood , Biomarkers/chemistry , Biosensing Techniques/instrumentation , Biosensing Techniques/methods , Electrochemical Techniques/instrumentation , Electrochemical Techniques/methods , Ferrous Compounds/chemistry , Humans , Immobilized Nucleic Acids/chemistry , Insulin-Like Growth Factor I/chemistry , Limit of Detection , Microelectrodes
15.
Mikrochim Acta ; 188(3): 71, 2021 02 06.
Article in English | MEDLINE | ID: mdl-33547976

ABSTRACT

A glassy carbon electrode (GCE) was modified with magnetic molecularly imprinted polymers (mMIPs) using catechin as a template, reduced graphene oxide (rGO), and zeolitic imidazolate frameworks-8 (ZIF-8) for the sensitive detection of catechin (mMIPs/rGO-ZIF-8/GCE). The prepared rGO, ZIF-8, and mMIPs exhibited typical structures and properties determined by various characterizations. The mMIPs showed good selectivity for catechin among several structural analogs. The mMIPs/rGO-ZIF-8/GCE showed a higher maximum peak current for catechin than that of a single component modified GCE. After the optimization of the material ratio, coating amounts, pH, and scan rate, the mMIPs/rGO-ZIF-8/GCE exhibited good selectivity, good linearity, and a low detection limit (LOD) for catechin. The linear range was 0.01 nmol/L-10 µmol/L and the LOD was 0.003 nmol/L (S/N = 3). The relative standard deviations for reproducibility and stability tests (n = 6) were 5.2% and 6.1%, respectively. A recovery between 99.1 and 101.3% was obtained in the detection of catechin in spiked samples. Based on these findings, the proposed mMIPs/rGO-ZIF-8/GCE could be developed further, and future research could be conducted on alternate fabrication strategies and methods to create more portable and practical electrochemical sensors. Graphical Abstract.


Subject(s)
Catechin/analysis , Graphite/chemistry , Imidazoles/chemistry , Molecularly Imprinted Polymers/chemistry , Nanocomposites/chemistry , Zeolites/chemistry , Adsorption , Catechin/chemistry , Electrochemical Techniques/instrumentation , Electrochemical Techniques/methods , Electrodes , Limit of Detection , Reproducibility of Results , Tea/chemistry
16.
Mikrochim Acta ; 187(7): 397, 2020 06 21.
Article in English | MEDLINE | ID: mdl-32564257

ABSTRACT

Gold nanoparticle (AuNP)-anchored BP nanosheets were synthesized through in situ growth of AuNPs onto BP. Due to the strong chelating ability of P or phosphorus oxides with AuNPs, the stability of BP is improved. As proof-of-concept demonstration of the functionalized BP, electrochemical detection of circulating tumor cells (CTCs) based on BP@AuNPs@aptamer as a probe combined with immunomagnetic separation is reported. The aptamer can specifically bind with CTCs, while the phosphorus oxides including phosphite ion and phosphate ion (PxOy species) on BP and aptamer can react with molybdate to generate an electrochemical current, leading to dual signal amplification. The biosensor is applied to MCF-7 cell detection and displays good analytical performance with a detection limit of 2 cell mL-1. Furthermore, the practicality of this biosensor was validated through sensitive determination of MCF-7 cells in human blood. Therefore, the reported biosensor could be applied to detect other biomarkers, offering an ultrasensitive strategy for clinical diagnostics. Graphical abstract Electrochemical detection of circulating tumor cells based on gold nanoparticle-modified black phosphorus nanosheets is reported.


Subject(s)
Biosensing Techniques/methods , Electrochemical Techniques/methods , Immunomagnetic Separation/methods , Metal Nanoparticles/chemistry , Neoplastic Cells, Circulating/chemistry , Phosphorus/chemistry , Antibodies, Immobilized/immunology , Aptamers, Nucleotide/chemistry , Base Sequence , Cell Line, Tumor , Epithelial Cell Adhesion Molecule/immunology , Gold/chemistry , Humans , Immobilized Nucleic Acids/chemistry , Limit of Detection , Molybdenum/chemistry , Mucin-1/chemistry , Neoplastic Cells, Circulating/immunology , Proof of Concept Study , Reproducibility of Results
17.
J Pharm Biomed Anal ; 186: 113253, 2020 Jul 15.
Article in English | MEDLINE | ID: mdl-32305737

ABSTRACT

A highly sensitive method for determining urine homogentisic acid (HGA) is required to provide adequate diagnosis and therapy for alkaptonuria in early stages. In this study, we developed a highly sensitive high-performance liquid chromatography with electrochemical detection (HPLC-ECD) for determining HGA in urine. In order to obtain a chromatogram of HGA by HPLC-ECD, an oxidation current was monitored at +0.5 V vs. Ag/AgCl. The peak heights of HGA showed linearity (r = 0.999) ranging from 4.2 ng/mL to 168 ng/mL, and the detection limit was 1.2 ng/mL (signal-to-noise ratio, S/N = 3). In recovery tests using human control urine spiked with an HGA standard, the recoveries of HGA were more than 93.2 %, and the relative standard deviations (n = 6) were less than 1.9 %. As an in vivo application using male Wistar rats, the level of urine HGA, which was metabolized from tyrosine in tyrosine-enriched food, was determined by this HPLC-ECD method. The determination of HGA in urine by this HPLC-ECD method requires only 0.1 mL of a rat urine specimen and simple sample preparation consisting of dilution and filtration.


Subject(s)
Homogentisic Acid/urine , Tyrosine/metabolism , Alkaptonuria/urine , Animal Feed , Animals , Chromatography, High Pressure Liquid , Electrochemical Techniques , Food, Fortified , Limit of Detection , Male , Rats , Rats, Wistar , Tandem Mass Spectrometry
18.
Diseases ; 7(2)2019 May 27.
Article in English | MEDLINE | ID: mdl-31137870

ABSTRACT

For the purpose of human disease prevention, several methods have been developed, and are still developing, to assess the oxidative stress status (OSS) of individuals. In the present paper, we describe an approach based on electrochemical detection able to evaluate skin oxidative stress status (SOSS) as a PAOT (Pouvoir AntiOxydant Total)-Skin Score®. Normal reference values for the PAOT-Skin Score® were: 0-62.94 (n = 263). Intra- and inter-assay coefficients of variation were, respectively, 12.47 ± 4.29% and 7.0 ± 2.5%. Our technology showed increased skin antioxidant activity following topical application of reduced coeznyme Q10 cream or vitamin C intake as orange juice or supplements. Moreover, we found significant correlations between some blood oxidative stress biomarkers and the PAOT-Skin Score ® (-tocopherol/α-tocopherol ratio (r = 0.43, p = 0.020); copper (r = -0.42, p = 0.022); copper/zinc ratio (r = -0.49, p = 0.006), and lipid peroxides (r = -0.43, p = 0.002)). In addition to being non-invasive, the present electrochemical methodology is also not expensive, fast, and easy to use.

19.
Talanta ; 200: 72-77, 2019 Aug 01.
Article in English | MEDLINE | ID: mdl-31036227

ABSTRACT

The sensitive monitoring of mercury (II) selenide nanoparticles (HgSe NPs) is of great potential relevance in environmental studies, since such NPs are believed to be the ultimate metabolic product of the lifesaving mechanism pathway of Hg detoxification in biological systems. In this context, we take advantage of using gold-nanostructured screen-printed carbon electrodes (SPCE-Au) for the rapid, simple and sensitive electrochemical quantification of engineered water-stable HgSe NPs, as an advantageous alternative to conventional elemental analysis techniques. HgSe NPs are first treated in an optimized oxidative/acidic medium for Hg2+ release, followed by sensitive electrochemical detection by anodic stripping voltammetry (ASV). To the best of our knowledge, this is the first time that water-stable HgSe NPs are quantified using electrochemical techniques. The low limit of detection achieved (3.86 × 107 HgSe NPs/mL) together with the excellent repeatability (RSD: 3%), reproducibility (RSD: 5%) and trueness (relative error: 10%), the good performance in real sea water samples (recoveries of the analytical signal higher than 90%) and the simplicity/low cost of analysis make our method an ideal candidate for HgSe NPs monitoring in future environmental studies.


Subject(s)
Electrochemical Techniques , Environmental Monitoring , Mercury/analysis , Nanoparticles/analysis , Selenium/analysis , Water Pollutants, Chemical/analysis
20.
Food Chem ; 289: 84-94, 2019 Aug 15.
Article in English | MEDLINE | ID: mdl-30955677

ABSTRACT

Developing selective and sensitive methods for tertiary butylhydroquinone (TBHQ) detection is of great significance to ensure the quality and safety of food. Herein, an electrochemical sensor was designed for selective and sensitive detection of TBHQ by integrating molecularly imprinted polymer, noble metal nanoparticles and carbon materials. The electrochemical sensor exhibited excellent performance for sensitive determination of TBHQ. The linear range was 0.5-60 µg mL-1 with a low detection limit of 0.046 µg mL-1. In addition, the results obtained by electrochemical method were well agreement with the detection results obtained by HPLC with good recoveries ranging from 99.4 to 108.5% in spiked edible oil samples. The present study not only has theoretical value to establish new methods for rapid detection of food additives but also has potential application values for monitoring the overuse of TBHQ.


Subject(s)
Electrochemical Techniques/methods , Hydroquinones/analysis , Molecular Imprinting , Plant Oils/chemistry , Polymers/chemistry , Carbon/chemistry , Chromatography, High Pressure Liquid , Electrochemical Techniques/instrumentation , Electrodes , Graphite/chemistry , Hydrogen-Ion Concentration , Limit of Detection , Metal Nanoparticles/chemistry
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