Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.951
Filtrar
1.
Biosens Bioelectron ; 166: 112431, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32862842

RESUMO

Last few decades, viruses are a real menace to human safety. Therefore, the rapid identification of viruses should be one of the best ways to prevent an outbreak and important implications for medical healthcare. The recent outbreak of coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus which belongs to the single-stranded, positive-strand RNA viruses. The pandemic dimension spread of COVID-19 poses a severe threat to the health and lives of seven billion people worldwide. There is a growing urgency worldwide to establish a point-of-care device for the rapid detection of COVID-19 to prevent subsequent secondary spread. Therefore, the need for sensitive, selective, and rapid diagnostic devices plays a vital role in selecting appropriate treatments and to prevent the epidemics. During the last decade, electrochemical biosensors have emerged as reliable analytical devices and represent a new promising tool for the detection of different pathogenic viruses. This review summarizes the state of the art of different virus detection with currently available electrochemical detection methods. Moreover, this review discusses different fabrication techniques, detection principles, and applications of various virus biosensors. Future research also looks at the use of electrochemical biosensors regarding a potential detection kit for the rapid identification of the COVID-19.


Assuntos
Betacoronavirus , Técnicas Biossensoriais/instrumentação , Técnicas de Laboratório Clínico/instrumentação , Infecções por Coronavirus/diagnóstico , Técnicas Eletroquímicas/instrumentação , Pneumonia Viral/diagnóstico , Vírus/isolamento & purificação , Animais , Betacoronavirus/isolamento & purificação , Betacoronavirus/patogenicidade , Infecções por Coronavirus/virologia , Desenho de Equipamento , Humanos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Varredura , Pandemias , Pneumonia Viral/virologia , Testes Imediatos , Vírus/patogenicidade
2.
Biosens Bioelectron ; 166: 112431, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: covidwho-654767

RESUMO

Last few decades, viruses are a real menace to human safety. Therefore, the rapid identification of viruses should be one of the best ways to prevent an outbreak and important implications for medical healthcare. The recent outbreak of coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus which belongs to the single-stranded, positive-strand RNA viruses. The pandemic dimension spread of COVID-19 poses a severe threat to the health and lives of seven billion people worldwide. There is a growing urgency worldwide to establish a point-of-care device for the rapid detection of COVID-19 to prevent subsequent secondary spread. Therefore, the need for sensitive, selective, and rapid diagnostic devices plays a vital role in selecting appropriate treatments and to prevent the epidemics. During the last decade, electrochemical biosensors have emerged as reliable analytical devices and represent a new promising tool for the detection of different pathogenic viruses. This review summarizes the state of the art of different virus detection with currently available electrochemical detection methods. Moreover, this review discusses different fabrication techniques, detection principles, and applications of various virus biosensors. Future research also looks at the use of electrochemical biosensors regarding a potential detection kit for the rapid identification of the COVID-19.


Assuntos
Betacoronavirus , Técnicas Biossensoriais/instrumentação , Técnicas de Laboratório Clínico/instrumentação , Infecções por Coronavirus/diagnóstico , Técnicas Eletroquímicas/instrumentação , Pneumonia Viral/diagnóstico , Vírus/isolamento & purificação , Animais , Betacoronavirus/isolamento & purificação , Betacoronavirus/patogenicidade , Infecções por Coronavirus/virologia , Desenho de Equipamento , Humanos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Varredura , Pandemias , Pneumonia Viral/virologia , Testes Imediatos , Vírus/patogenicidade
3.
Biosens Bioelectron ; 169: 112604, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32980805

RESUMO

Virus severely endangers human life and health, and the detection of viruses is essential for the prevention and treatment of associated diseases. Metal-organic framework (MOF), a novel hybrid porous material which is bridged by the metal clusters and organic linkers, has become a promising biosensor platform for virus detection due to its outstanding properties including high surface area, adjustable pore size, easy modification, etc. However, the MOF-based sensing platforms for virus detection are rarely summarized. This review systematically divided the detection platforms into nucleic acid and immunological (antigen and antibody) detection, and the underlying sensing mechanisms were interpreted. The nucleic acid sensing was discussed based on the properties of MOF (such as metal ion, functional group, geometry structure, size, porosity, stability, etc.), revealing the relationship between the sensing performance and properties of MOF. Moreover, antibodies sensing based on the fluorescence detection and antigens sensing based on molecular imprinting or electrochemical immunoassay were highlighted. Furthermore, the remaining challenges and future development of MOF for virus detection were further discussed and proposed. This review will provide valuable references for the construction of sophisticated sensing platform for the detection of viruses, especially the 2019 coronavirus.


Assuntos
Técnicas Biossensoriais/métodos , Estruturas Metalorgânicas/química , Viroses/virologia , Vírus/isolamento & purificação , Animais , Anticorpos Antivirais/análise , Antígenos Virais/análise , Técnicas Biossensoriais/instrumentação , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Modelos Moleculares , Impressão Molecular/instrumentação , Impressão Molecular/métodos , Ácidos Nucleicos/análise , Espectrometria de Fluorescência/instrumentação , Espectrometria de Fluorescência/métodos , Viroses/diagnóstico
4.
ACS Sens ; 5(9): 2747-2752, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32820626

RESUMO

With the current intense need for rapid and accurate detection of viruses due to COVID-19, we report on a platform technology that is well suited for this purpose, using intact measles virus for a demonstration. Cases of infection due to the measles virus are rapidly increasing, yet current diagnostic tools used to monitor for the virus rely on slow (>1 h) technologies. Here, we demonstrate the first biosensor capable of detecting the measles virus in minutes with no preprocessing steps. The key sensing element is an electrode coated with a self-assembled monolayer containing the measles antibody, immobilized through an N-heterocyclic carbene (NHC). The intact virus is detected by changes in resistance, giving a linear response to 10-100 µg/mL of the intact measles virus without the need to label or process the sample. The limit of detection is 6 µg/mL, which is at the lower limit of concentrations that can cause infections in primates. The NHC-based biosensors are shown to be superior to thiol-based systems, producing an approximately 10× larger response and significantly greater stability toward repeated measurements and long-term storage. This NHC-based biosensor thus represents an important development for both the rapid detection of the measles virus and as a platform technology for the detection of other biological targets of interest.


Assuntos
Anticorpos Imobilizados/imunologia , Benzimidazóis/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Vírus do Sarampo/isolamento & purificação , Anticorpos Imobilizados/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Ouro/química , Limite de Detecção , Vírus do Sarampo/imunologia
5.
ACS Sens ; 5(9): 2747-2752, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: covidwho-740029

RESUMO

With the current intense need for rapid and accurate detection of viruses due to COVID-19, we report on a platform technology that is well suited for this purpose, using intact measles virus for a demonstration. Cases of infection due to the measles virus are rapidly increasing, yet current diagnostic tools used to monitor for the virus rely on slow (>1 h) technologies. Here, we demonstrate the first biosensor capable of detecting the measles virus in minutes with no preprocessing steps. The key sensing element is an electrode coated with a self-assembled monolayer containing the measles antibody, immobilized through an N-heterocyclic carbene (NHC). The intact virus is detected by changes in resistance, giving a linear response to 10-100 µg/mL of the intact measles virus without the need to label or process the sample. The limit of detection is 6 µg/mL, which is at the lower limit of concentrations that can cause infections in primates. The NHC-based biosensors are shown to be superior to thiol-based systems, producing an approximately 10× larger response and significantly greater stability toward repeated measurements and long-term storage. This NHC-based biosensor thus represents an important development for both the rapid detection of the measles virus and as a platform technology for the detection of other biological targets of interest.


Assuntos
Anticorpos Imobilizados/imunologia , Benzimidazóis/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Vírus do Sarampo/isolamento & purificação , Anticorpos Imobilizados/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Ouro/química , Limite de Detecção , Vírus do Sarampo/imunologia
6.
PLoS One ; 15(8): e0237583, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804936

RESUMO

Identification and quantification of plant flavonoids are critical to pharmacokinetic study and pharmaceutical quality control due to their distinct pharmacological functions. Here we report on a novel plant flavonoid electrochemical sensor for sensitive and selective detection of dihydromyricetin (DMY) based on double- layered membranes consisting of gold nanoparticles (Au) anchored on reduced graphene oxide (rGO) and molecularly imprinted polymers (MIPs) modified glassy carbon electrode (GCE). Both rGO-Au and MIPs membranes were directly formed on GCE via in-situ electrochemical reduction and polymerization processes step by step. The compositions, morphologies, and electrochemical properties of membranes were investigated with X-ray powder diffractometry (XRD), Fourier transform infrared spectrum (FTIR), Field emission scanning electron microscopy (FESEM) combined with various electrochemical methods. The fabricated electrochemical sensor labeled as GCE│rGO-Au/MIPs exhibited excellent performance in determining of DMY under optimal experimental conditions. A wide linear detection range (LDR) ranges from 2.0×10-8 to 1.0×10-4 M together with a low limit of detection (LOD) of 1.2×10-8 M (S/N = 3) were achieved. Moreover, the electrochemical sensor was employed to determine DMY in real samples with satisfactory results.


Assuntos
Carbono/química , Técnicas Eletroquímicas/instrumentação , Flavonoides/análise , Flavonóis/análise , Grafite/química , Técnicas Biossensoriais/métodos , Eletrodos , Ouro , Limite de Detecção , Nanopartículas Metálicas , Impressão Molecular , Extratos Vegetais/análise , Polímeros/síntese química , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
7.
Nat Commun ; 11(1): 3743, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32719350

RESUMO

Ions are ubiquitous biological regulators playing a key role for vital processes in animals and plants. The combined detection of ion concentration and real-time monitoring of small variations with respect to the resting conditions is a multiscale functionality providing important information on health states. This multiscale functionality is still an open challenge for current ion sensing approaches. Here we show multiscale real-time and high-sensitivity ion detection with complementary organic electrochemical transistors amplifiers. The ion-sensing amplifier integrates in the same device both selective ion-to-electron transduction and local signal amplification demonstrating a sensitivity larger than 2300 mV V-1 dec-1, which overcomes the fundamental limit. It provides both ion detection over a range of five orders of magnitude and real-time monitoring of variations two orders of magnitude lower than the detected concentration, viz. multiscale ion detection. The approach is generally applicable to several transistor technologies and opens opportunities for multifunctional enhanced bioelectronics.


Assuntos
Amplificadores Eletrônicos , Sistemas Computacionais , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Íons/análise , Compostos Orgânicos/química , Transistores Eletrônicos , Eletricidade , Humanos , Íons/sangue , Potássio/análise
8.
Biosens Bioelectron ; 165: 112435, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32729548

RESUMO

COVID-19 is the shocking viral pandemics of this year which affected the health, economy, communications, and all aspects of social activities all over the world. Early diagnosis of this viral disease is very important since it can prevent lots of mortalities and care consumption. The functional similarities between COVID-19 and COVID-2 in inducing acute respiratory syndrome lightened our mind to find a diagnostic mechanism based on early traces of mitochondrial ROS overproduction as lung cells' dysfunctions induced by the virus. We designed a simple electrochemical sensor to selectively detect the intensity of ROS in the sputum sample (with a volume of less than 500 µl). Comparing the results of the sensor with clinical diagnostics of more than 140 normal and involved cases resulted in a response calibration with accuracy and sensitivity both 97%. Testing the sensor in more than 4 hospitals shed promising lights in ROS based real-time tracing of COVID-19 from the sputum sample.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais/métodos , Infecções por Coronavirus/diagnóstico , Técnicas Eletroquímicas/métodos , Pneumonia Viral/diagnóstico , Espécies Reativas de Oxigênio/análise , Escarro/virologia , Adulto , Idoso , Técnicas Biossensoriais/instrumentação , Infecções por Coronavirus/virologia , Diagnóstico Precoce , Técnicas Eletroquímicas/instrumentação , Desenho de Equipamento , Feminino , Humanos , Pulmão/química , Pulmão/virologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/virologia , Sensibilidade e Especificidade , Escarro/química , Adulto Jovem
9.
Biosens Bioelectron ; 165: 112435, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: covidwho-635645

RESUMO

COVID-19 is the shocking viral pandemics of this year which affected the health, economy, communications, and all aspects of social activities all over the world. Early diagnosis of this viral disease is very important since it can prevent lots of mortalities and care consumption. The functional similarities between COVID-19 and COVID-2 in inducing acute respiratory syndrome lightened our mind to find a diagnostic mechanism based on early traces of mitochondrial ROS overproduction as lung cells' dysfunctions induced by the virus. We designed a simple electrochemical sensor to selectively detect the intensity of ROS in the sputum sample (with a volume of less than 500 µl). Comparing the results of the sensor with clinical diagnostics of more than 140 normal and involved cases resulted in a response calibration with accuracy and sensitivity both 97%. Testing the sensor in more than 4 hospitals shed promising lights in ROS based real-time tracing of COVID-19 from the sputum sample.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas Biossensoriais/métodos , Infecções por Coronavirus/diagnóstico , Técnicas Eletroquímicas/métodos , Pneumonia Viral/diagnóstico , Espécies Reativas de Oxigênio/análise , Escarro/virologia , Adulto , Idoso , Técnicas Biossensoriais/instrumentação , Infecções por Coronavirus/virologia , Diagnóstico Precoce , Técnicas Eletroquímicas/instrumentação , Desenho de Equipamento , Feminino , Humanos , Pulmão/química , Pulmão/virologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/virologia , Sensibilidade e Especificidade , Escarro/química , Adulto Jovem
10.
Food Chem ; 333: 127495, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32663747

RESUMO

Various pesticides employed in modern agriculture result in large amounts of pesticide residues in agricultural production, greatly threatening human health. Herein, we report a facile approach to fabricate a reduced graphene oxide/cyclodextrin modified glassy carbon electrode (rGO/CD/GCE) for the sensitive electrochemical sensing of imidacloprid (IDP). Three different modified electrodes using CDs (α-, ß-, γ-CD) were fabricated, and their electrochemical performance was further studied. The results demonstrate that α-CD possesses the best signal amplification for IDP. Compared with wet-chemical synthesis of rGO/CDs (W-rGO/CDs), the electrochemical synthesis of rGO/CDs (E-rGO/CDs) produced sensors that showed better performance for IDP sensing. Taking advantage of prepared E-rGO/α-CD nanocomposite, the fabricated sensor offered a low detection limit (0.02 µM) with a wider linear range (0.5-40 µM) and long-term stability. The new sensor was successfully applied for the detection of IDP in brown rice, providing a new technique for efficient and convenient monitoring of pesticide residues in food.


Assuntos
Ciclodextrinas/química , Técnicas Eletroquímicas/métodos , Grafite/química , Inseticidas/análise , Neonicotinoides/análise , Nitrocompostos/análise , Oryza/química , Carbono/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Contaminação de Alimentos/análise , Nanocompostos/química , Oxirredução , Sementes/química , Sensibilidade e Especificidade
11.
Food Chem ; 331: 127368, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32569962

RESUMO

A novel strategy for AFB1 detection in grains was proposed based on DNA tetrahedron-structured probe (DTP) and horseradish peroxidase (HRP) triggered polyaniline (PANI) deposition. Briefly, the DNA tetrahedron nanostructures were assembled on the gold electrode, with carboxylic group designed on top vertex of them. The carboxylic group was conjugated with the AFB1 monoclonal antibody (mAb) to form DTP. The test sample and a known fixed concentration of HRP-labeled AFB1 were mixed and they compete for binding to DTP. The HRP assembled on the gold electrode catalyzed the polymerization of aniline on DTP. AFB1 in grains could be determined by using PANI as electrochemical signal molecules. Interestingly, DNA tetrahedron-structure, which has mechanical rigidity and structural stability, can improve antigen-antibody specific recognition and binding efficiency through the use of mAb ordered assembly. Meanwhile, nucleic acid backbone with a large amount of negative charge is good template for aniline polymerization under mild conditions.


Assuntos
Aflatoxina B1/análise , Compostos de Anilina/química , Técnicas Eletroquímicas/métodos , Contaminação de Alimentos/análise , Nanoestruturas/química , Aflatoxina B1/imunologia , Anticorpos Monoclonais/química , DNA/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Ouro/química , Peroxidase do Rábano Silvestre/química , Polimerização , Sensibilidade e Especificidade
12.
PLoS One ; 15(6): e0234981, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32574186

RESUMO

The corrosion behavior of an AZ91D magnesium alloy was investigated under a heterogeneous electrolyte layer by using electrochemical methods and surface analysis techniques. Dynamic polarization curves and morphological characterization were obtained at the center and near the edge zones under the electrolyte layer. The influence of the gas/liquid/solid three-phase boundary zone (TPB) on the corrosion behavior of the AZ91D magnesium alloy was discussed. The corrosion rate changed more significantly near the TPB zone than that at the other zones. The AZ91D alloy exhibited the characteristics of filiform corrosion together with shallow pitting corrosion. Different from the randomly distributed shallow pits, the filiform corrosion preferred to initiate near the TPB region and then progressively expanded adjacent to the edge of the electrolyte layer. The TPB zone played a vital role in determining the corrosion location, the corrosion morphologies and the corrosion rate of the magnesium alloy by influencing the mass transport process of carbon dioxide.


Assuntos
Ligas/química , Eletrólitos/química , Magnésio/química , Corrosão , Técnicas Eletroquímicas/instrumentação , Eletrodos , Propriedades de Superfície , Difração de Raios X
13.
Chemosphere ; 255: 126964, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32416391

RESUMO

A water quality early-warning instrument for evaluating acute water toxicity based on the electrochemical biosensor, Model ETOX18-01, was developed and manufactured with the features of low current detection (0.1 nA), precise thermostatic control, self-cleaning as well as remote data transmission. A sensitive integrated microbial electrode, made up of a glass carbon electrode that was modified by an active biofilm consisting of Escherichia coli, thionine, carbon nanodots and chitosan, has been fabricated as the biosensor. To validate the performance, multiple real water samples and artificial water samples were tested by Model ETOX18-01, and compared with ISO standardized luminescent bacterial test simultaneously. The correlation between the Model ETOX18-01 and luminescent bacterial test for these water samples showed good determination coefficient (R2 = 0.9827). In addition, Model ETOX18-01 is more sensitive to colored metal ionic samples. With its characteristics of high sensitivity, excellent repeatability and easy operation, the instrument Model ETOX18-01 provides a promising tool for large-scale water environmental assessment, and has a potential application in evaluating the water quality and early risk warning.


Assuntos
Técnicas Biossensoriais/instrumentação , Monitoramento Ambiental/instrumentação , Poluentes Químicos da Água/análise , Carbono , Quitosana/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Monitoramento Ambiental/métodos , Íons , Fenotiazinas , Água , Poluentes Químicos da Água/toxicidade
14.
Food Chem ; 322: 126762, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32283369

RESUMO

A novel electrochemical aptasensor modified with highly porous gold and aptamer was prepared for the determination of acetamiprid in fruits and vegetables. Highly porous gold was synthesized by electroreduction at -4 V in an electrolyte containing 2.5 mol/L NH4Cl and 10 mmol/L HAuCl4. Acetamiprid-binding aptamer was immobilized on highly porous gold by self-assembly. Acetamiprid could be captured by aptamer on the sensing interface, resulting in an increment of electron transfer resistance. Thanks to the large specific surface area of highly porous gold and the high affinity of aptamer, the aptasensor exhibited a highly sensitive impedance response for acetamiprid. Under optimal condition, the aptasensor displayed a linear response for acetamiprid in the concentration range of 0.5-300 nmol/L, and the detection limit was 0.34 nmol/L. Furthermore, the aptasensor showed high selectivity, good reproducibility and stability. Finally, the aptasensor was applied for the determination of acetamiprid in fruits and vegetables with satisfactory results.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Eletroquímicas/métodos , Análise de Alimentos/métodos , Neonicotinoides/análise , Impedância Elétrica , Técnicas Eletroquímicas/instrumentação , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Frutas/química , Ouro/química , Limite de Detecção , Praguicidas/análise , Porosidade , Reprodutibilidade dos Testes , Verduras/química
15.
Artigo em Inglês | MEDLINE | ID: mdl-32255737

RESUMO

A new and sensitive electrochemical sensor for rutin determination was developed based on cetyltrimethylammonium chloride (CTAC) functionalized graphene (Gr) and palladium nanoparticles (Pd) (CTAC-Gr-PdNPs) composite. Rutin displayed remarkably increased electrochemical activity on the CTAC-Gr-PdNPs composite modified electrode due to the synergistic effect of the large surface area and electrocatalytic activity of both Gr and Pd nanoparticles, which offers the feasibility for highly sensitive determination of rutin via electrochemistry. Under the optimal experimental conditions, the oxidation peak current of rutin was proportional to its concentration in the range of 2.0 × 10-8-1.0 × 10-6 mol L-1, and the limit of detection (LOD) was 5 nM (S/N = 3). The developed method was successfully applied to determine rutin in pharmaceuticals with satisfactory recoveries, which shows that the fabricated sensor has potential in pharmaceutical analysis.


Assuntos
Técnicas Eletroquímicas/métodos , Grafite/química , Nanopartículas Metálicas/química , Paládio/química , Rutina/análise , Técnicas Eletroquímicas/instrumentação , Eletroquímica , Eletrodos , Desenho de Equipamento , Limite de Detecção , Oxirredução , Rutina/farmacologia
16.
Int J Nanomedicine ; 15: 2219-2230, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32280216

RESUMO

Purpose: In the present study, a highly sensitive and simple electrochemical (EC) aptasensor for the detection of serpin A12 as a novel biomarker of diabetes was developed on a platform where flower-like gold microstructures (FLGMs) are electrodeposited onto a disposable screen-printed carbon electrode. Meanwhile, serpin A12-specific thiolated aptamer was covalently immobilized on the FLGMs. Methods: The electrochemical activity of a fabricated aptasensor under various conditions were examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Aptamer concentration, deposition time, self-assembly time, and incubation time were optimized for assay of serpin A12. The differential pulse voltammetry (DPV) was implemented for quantitative detection of serpin A12 in K3 [Fe (CN) 6]/K4 [Fe (CN) 6] solution (redox probe). Results: The label-free aptasensor revealed a linear range of serpin A12 concentration (0.039-10 ng/mL), detection limit of 0.020 ng/mL (S/N=3), and 0.031 ng/mL in solution buffer and plasma, respectively. Conclusion: The results indicate that this aptasensor has a high sensitivity, selectivity, stability, and acceptable reproducibility for detection of serpin A12 in diabetic patients.


Assuntos
Aptâmeros de Nucleotídeos/química , Diabetes Mellitus Tipo 2/sangue , Técnicas Eletroquímicas/instrumentação , Eletrodos , Serpinas/sangue , Animais , Biomarcadores/sangue , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Carbono/química , Diabetes Mellitus Experimental/sangue , Espectroscopia Dielétrica/métodos , Técnicas Eletroquímicas/métodos , Galvanoplastia , Desenho de Equipamento , Ouro/química , Limite de Detecção , Masculino , Ratos Wistar , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Nat Commun ; 11(1): 838, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-32047166

RESUMO

Protein-protein interactions are spatially regulated in living cells to realize high reaction efficiency, as seen in naturally existing electron-transfer chains. Nevertheless, arrangement of chemical/biochemical components at the artificial device interfaces does not possess the same level of control. Here we report a tetrahedral DNA framework-enabled bulk enzyme heterojunction (BEH) strategy to program the multi-enzyme catalytic cascade at the interface of electrochemical biosensors. The construction of interpenetrating network of BEH at the millimeter-scale electrode interface brings enzyme pairs within the critical coupling length (CCL) of ~10 nm, which in turn greatly improve the overall catalytic cascade efficiency by ~10-fold. We demonstrate the BEH generality with a range of enzyme pairs for electrochemically detecting clinically relevant molecular targets. As a proof of concept, a BEH-based sarcosine sensor enables single-step detection of the metabolic biomarker of sarcosine with ultrasensitivity, which hold the potential for precision diagnosis of early-stage prostate cancer.


Assuntos
Técnicas Biossensoriais/métodos , DNA/química , Técnicas Eletroquímicas/métodos , Eletrodos , Enzimas Imobilizadas , Técnicas Biossensoriais/instrumentação , Catálise , Técnicas de Química Analítica/métodos , Técnicas Eletroquímicas/instrumentação , Enzimas/química , Desenho de Equipamento , Humanos , Limite de Detecção , Nanopartículas Metálicas , Modelos Teóricos , Nanotecnologia/métodos , Sarcosina
18.
Chemosphere ; 248: 126033, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32004882

RESUMO

Degradation of phenols with different substituent groups (including -OCH3, -CHO, -NHCOCH3, -NO2, and -Cl) at boron-doped diamond (BDD) anodes has been studied previously based on the removal efficiency and •OH detection. Innovatively, formations of CO2 gas and various inorganic ions were examined to probe the mineralization process combined with quantitative structure-activity relationship (QSAR) analysis. As results, all phenols were efficiently degraded within 8 h with high COD removal efficiency. Three primary intermediates (hydroquinone, 1,4-benzoquinone and catechol) were identified during electrochemical oxidation and degradation pathway was proposed. More importantly, CO2 transformation efficiency ranked as: no N or Cl contained phenols (p-CHO, p-OCH3 and Ph) > N-contained phenols (p-NHCOCH3 and p-NO2) > Cl-contained phenols (p-Cl and o,p-Cl). Carbon mass balance study suggested formation of inorganic carbon (H2CO3, CO32- and HCO3-) and CO2 after organic carbon elimination. Inorganic nitrogen species (NH4+, NO3- and NO2-) and chlorine species (Cl-, ClO3- and ClO4-) were also formed after N- and Cl-contained phenols mineralization, while no volatile nitrogen species were detected. The phenols with electron-withdrawing substituents were easier to be oxidized than those with electron-donating substituents. QSAR analysis indicated that the reaction rate constant (k1) for phenols degradation was highly related to Hammett constant (∑σo,m,p) and energy gap (ELUMO - EHOMO) of the compound (R2 = 0.908), which were key parameters on evaluating the effect of structural moieties on electronic character and the chemical stability upon radical attack for a specific compound. This study presents clear evidence on mineralization mechanisms of phenols degradation at BDD anodes.


Assuntos
Técnicas Eletroquímicas/instrumentação , Eletrodos , Fenóis/química , Relação Quantitativa Estrutura-Atividade , Poluentes Químicos da Água/química , Análise da Demanda Biológica de Oxigênio , Boro/química , Carbono/química , Dióxido de Carbono/química , Cloro/química , Diamante/química , Nitrogênio/química , Oxirredução
19.
Chemosphere ; 248: 126029, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32035385

RESUMO

The use of electrokinetic Fenton (EK Fenton) process, as promising soil remediation approach, was investigated by using an iron electrode with different supporting electrolytes (tap water, H2O2, and citric acid) to depollute soil spiked with petroleum where kaolin was selected as low hydraulic conductivity. The results clearly confirm that, the combination of electrokinetic remediation (EK) and Fenton technologies, is an efficient oxidizing approach for removing hydrocarbons from this kind of soil. In fact, the electrokinetic Fenton reactions and the control of the soil pH conditions by adding citric acid enhanced the oxidation process because the addition of the H2O2 with iron electrode resulted in higher removal efficiencies (89%) for total petroleum hydrocarbons (TPHs). These figures allowed to confirm that EK Fenton process with pH control contributed for the transport of H2O2 and Fe2+ ions in the soil by electromigration and eletro-osmotic phenomena. Conversely, no control of pH conditions when only EK was applied, achieved lower hydrocarbons removal (27%) after 15 d of treatment due to the precipitation of iron ions. Finally, the efficiency of the EK Fenton remediation prevented the generation of secondary effluent with higher organic content, avoiding its treatment by other advanced oxidation process.


Assuntos
Recuperação e Remediação Ambiental/métodos , Poluição por Petróleo , Poluentes do Solo/química , Ácido Cítrico/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Recuperação e Remediação Ambiental/instrumentação , Hidrocarbonetos/química , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Ferro/química , Caulim/química , Osmose , Oxirredução , Solo/química
20.
Anal Bioanal Chem ; 412(8): 1825-1833, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32002581

RESUMO

A selective cortisol sensor based on molecularly imprinted poly(glycidylmethacrylate-co ethylene glycol dimethacrylate) (poly(GMA-co-EGDMA)) has been demonstrated for detection of cortisol in human sweat. The non-enzymatic biomimetric flexible sweat sensor was fabricated inexpensively by layer by layer (LbL) assembly. The sensor layers comprised a stretchable polydimethylsiloxane (PDMS) base with carbon nanotubes-cellulose nanocrystals (CNC/CNT) conductive nanoporous nanofilms. The imprinted (MIP) poly(GMA-co-EGDMA) deposited on the CNC/CNT was the cortisol biomimetric receptor. Rapid in analyte response (3 min), the cortisol MIP sensor demonstrated excellent performance. The sensor has a limit of detection (LOD) of 2.0 ng/mL ± 0.4 ng/mL, dynamic range of 10-66 ng/mL, and a sensor reproducibility of 2.6% relative standard deviation (RSD). The MIP sensor also had high cortisol specificity and was inherently blind to selected interfering species including glucose, epinephrine, ß-estradiol, and methoxyprogestrone. The MIP was four orders of magnitude more sensitive than its non-imprinted (NIP) counterpart. The MIP sensor remains stable over time, responding proportionately to doses of cortisol in human sweat. Graphical abstract.


Assuntos
Técnicas Eletroquímicas/instrumentação , Eletrodos , Hidrocortisona/análise , Impressão Molecular , Suor/química , Humanos , Limite de Detecção , Reprodutibilidade dos Testes , Dispositivos Eletrônicos Vestíveis
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA