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1.
J Hazard Mater ; 401: 123794, 2021 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-33113737

RESUMO

In this work, an ultrasensitive and selective electrochemiluminescence (ECL) aptasensor with Au-tetrahedral aptamer nanostructure (Au-TAN) for acetamiprid detection was developed, which employed luminescence property of luminol and hydrogen peroxide (H2O2) as a co-reactant to apply the prepared Au-TAN to the luminescence systems. Au-TAN was prepared to modify an electrode surface via an Au-S bond to form a stable tetrahedral nanostructure. Fixed on the surface of the working electrode, Au-TAN could not only enhance the function of the aptamer but also boost the sensing performance. At the same time, Au nanoparticles (AuNPs) of the Au-TAN could also catalyze H2O2, thereby enhancing the luminescence performance of this aptasensor. The pH of the buffer solution, the concentration of H2O2 and the concentration of Au-TAN were optimized. Under the optimal conditions, the aptasensor had a detection limit of 0.0576 pM (S/N = 3), which was lower than those of other aptasensors for acetamiprid detection. Moreover, the weak alkaline environment explored in the experiment could expand its application range. Above all, the proposed method presented a high accuracy and sensitivity.

2.
Artigo em Inglês | MEDLINE | ID: mdl-33161490

RESUMO

Broad-spectrum antibodies can effectively recognize substances with similar structures and have broad application prospects in field rapid detection. In this study, broad-spectrum antibodies (Abs) against organophosphorus pesticides (OPs) were used as sensitive recognition elements, which could effectively recognize most OPs. Gold nanoparticles (AuNPs) have good biocompatibility. It combined with Abs to form a gold-labeled probe (AuNPs-Abs), which enhances the effective binding of antibodies to nanomaterials. Prussian blue (PB) was added to electrodeposition solution to enhance the conductivity, resulting in superior electrochemical performance. The AuNP-Abs-PB composite film was prepared by electrodeposition on the electrode surface to improve the anti-interference ability and stability of the immunosensor. Under the optimal experimental conditions, the immunosensor had a wide detection range (IC20-IC80: 1.82 × 10-3-3.29 × 104 ng/mL) and high sensitivity. Most importantly, it was simple to be prepared and could be used to detect multiple OPs.

3.
Sensors (Basel) ; 20(22)2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33217912

RESUMO

Immunoassay has the advantages of high sensitivity, high specificity, and simple operation, and has been widely used in the detection of mycotoxins. For several years, time-resolved fluorescence immunochromatography (TRFIA) paper-based sensors have attracted much attention as a simple and low-cost field detection technology. However, a traditional TRFIA paper-based sensor is based on antibody labeling, which cannot easily meet the current detection requirements. A second antibody labeling method was used to amplify the fluorescence signal and improve the detection sensitivity. Polystyrene fluorescent microspheres were combined with sheep anti-mouse IgG to prepare fluorescent probes (Eu-IgGs). After the probe fully reacted with the antibody (Eu-IgGs-Abs) in the sample cell, it was deployed on the paper-based sensor using chromatography. Eu-IgGs-Abs that were not bound to the target were captured on the T-line, while those that were bound were captured on the C-line. The paper-based sensor reflected the corresponding fluorescence intensity change. Because a single molecule of the deoxynivalenol antibody could bind to multiple Eu-IgGs, this method could amplify the fluorescence signal intensity on the unit antibody and improve the detection sensitivity. The working standard curve of the sensor was established under the optimum working conditions. It showed the lower limit of detection and higher recovery rate when it was applied to actual samples and compared with other methods. This sensor has the advantages of high sensitivity, good accuracy, and good specificity, saving the amount of antibody consumed and being suitable for rapid field detection of deoxynivalenol.

4.
Sci Total Environ ; : 143129, 2020 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-33121792

RESUMO

Aminoglycoside antibiotics (AAs) have been extensively applied in medical field and animal husbandry owing to desirable broad-spectrum antibacterial activity. Excessive AAs residues in the environment can be accumulated in human body through food chain and cause detrimental effect on human health. The establishment of highly specific, simple and sensitive detection methods for monitoring AAs residues is highly in demand. Aptasensor using aptamer as the biological recognition element is the efficient and promising sensing method for detection of AAs. In this review, we have made a summary of specific aptamers sequences against AAs. Subsequently, we provide a systematical and comprehensive overview of modern techniques in aptasensors for detection of AAs according to optical aptasensors as well as electrochemical aptasensors and further summarize their advantages and disadvantages to compare their applications. In addition, we present an overview of practical applications of aptasensors in sample detection of AAs. Moreover, the current challenges and future trends in this field are also included to reveal a promising perspective for developing novel aptasensors for AAs.

5.
Sci Total Environ ; 737: 139785, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32516665

RESUMO

In order to effectively monitor the residue of kanamycin (KAN), a dual-signal-amplified electrochemiluminescence (ECL) aptasensor based on multi-walled carbon nanotubes@titanium dioxide/thionine (MWCNTs@TiO2/Thi) was proposed. MWCNTs@TiO2 with large specific surface area and favorable biocompatibility could accelerate charge transfer and enable high loading of luminol to enhance ECL response. As a perfect electronic mediator, Thi could also accelerate electron conductivity to further enhance ECL intensity. The ECL intensity of MWCNTs@TiO2/Thi was enhanced for 3.6-fold compared with that of individual Thi because Thi could strongly interact with MWCNTs through π-π stacking force to enhance the electronic transmission. With the outstanding electron transfer property of MWCNTs@TiO2 and Thi, ECL intensity of the proposed aptasensor was obviously increased. Upon addition of KAN, the aptamer bound to its target, which caused that the ECL intensity decrease significantly. Therefore, KAN concentration could be monitored on the basis of signal intensity. Under optimal conditions, the constructed aptasensor exhibited a sensitive response towards KAN and a low detection limit of 0.049 ng mL-1 was obtained. It also possessed the excellent specificity, favorable stability and good reproducibility. Importantly, the application of proposed ECL aptasensor provides an efficient approach for highly sensitive detection of various small molecular contaminants.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Nanotubos de Carbono , Técnicas Eletroquímicas , Canamicina , Medições Luminescentes , Reprodutibilidade dos Testes
6.
Sci Total Environ ; 712: 136410, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32050375

RESUMO

In order to solve the problem that the sensor cannot be reused due to the passivation of the electrode surface, a refreshable electrochemical aptasensor based on a hydrophobic electrode and a magnetic nanocomposite had been developed. Therein, the hydrophobic electrode was formed by modifying a screen-printed carbon electrode (SPCE) with polydimethylsiloxane (PDMS), which could avoid adsorption of molecules on the electrode surface due to its hydrophobicity. Combined with aptamer (Apt), the synthesized graphene oxide-ferroferric oxide (GO-Fe3O4) was used as a magnetic catcher to capture specific organophosphorus pesticides (OPs), which could be removed to the working area of SPCE with a magnet for electrochemical detection. The performance analysis of hydrophobic electrode showed that the SPCE could be used twice. When the electrochemical signals of Apt/GO-Fe3O4 and OPs/Apt/GO-Fe3O4 were recorded using the same SPCE, the current differences between them were directly related to the concentrations of OPs. Through the contrast test between the spiked vegetable samples and the OPs standard solutions, it was found that the OPs concentrations could be qualitatively evaluated by comparing the current differences. At the same time, the characteristic of collecting target with magnetic catcher was helpful for detecting OPs with a low concentration. Therefore, the refreshable aptasensor provided a huge potential to small molecule target evaluation.

7.
Sci Total Environ ; 705: 135905, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-31838423

RESUMO

In this work, a novel dual signal amplification strategy for aptasensor employing reduced graphene with silver nanoparticles and prussian blue-gold nanocomposites was developed for detection of acetamiprid. To improve the sensitivity of aptasensors, reduced graphene oxide-silver nanoparticles (rGo-AgNPs) were modified on a bare glassy carbon electrode surface, which provided a large specific surface area for subsequent material immobilization and amplified current signal. The electrical signal output and sensitivity of the aptasensor was significantly improved after the immobilization of prussian blue-gold nanoparticles (PB-AuNPs) as a catalyst for the redox reaction. The analysis experiment exhibited that it had super-high sensitivity with a detection limit of 0.30 pM (S/N = 3), which met the requirements of the vast majority of daily leaf vegetable testing. Under optimized conditions, the proposed aptasensor showed a wide linear detection range from 1 pM to 1 µM. This aptasensor also had good stability and high selectivity for acetamiprid detection without an interfering effect of some other pesticides. The proposed aptasensor displayed good recovery rates in real samples, which proposed a new method for constructing electrochemical sensors and provided a novel tool for rapid, sensitive analysis of pesticides with low cost.


Assuntos
Neonicotinoides/química , Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Técnicas Eletroquímicas , Ouro , Grafite , Limite de Detecção , Nanopartículas Metálicas , Prata
8.
Mikrochim Acta ; 187(1): 36, 2019 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-31820139

RESUMO

An aptasensor is described for electrochemical determination of organophosphorus pesticides (OPPs), specifically of profenofos, phorate, isocarbophos, and omethoate. The method uses a hairpin aptamer as signalling donor. Its 5' and 3' ends were modified with amino groups and the redox probe ferrocene (Fc), respectively. A nanocomposite consisting of graphene oxide and chitosan (GO-chit) was used to immobilize the aptamer via formation of an amide link. Its good conductivity facilitates monitoring of the electrochemical responses. Upon addition of an OPP, it will be bound by the aptamer. This results in an opening of the hairpin structure. Thus, Fc is shifted away from the surface of the electrode. As a result, the impedance increases and the redox signal of Fc decreases. The electrochemical performance, binding capacity and response of the aptasensor for profenofos, phorate, isocarbophos and omethoate were studied. The limits of detection are as low as 0.01, 0.1, 0.01 and 0.1 nM, respectively. Graphical abstract Schematic representation of an electrochemical aptasensor prepared by immobilizing ferrocene (Fc) labeled hairpin aptamer (HP) on the surface of graphene oxide-chitosan (GO-chit) modified electrode, and its application to the determination of organophosphorus pesticides (OPPs) by voltammetry.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Técnicas Eletroquímicas , Compostos Organofosforados/análise , Praguicidas/análise , Quitosana/química , Grafite/química , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
9.
Sensors (Basel) ; 19(8)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999637

RESUMO

The Internet of Things (IoT) has tremendous success in health care, smart city, industrial production and so on. Protected agriculture is one of the fields which has broad application prospects of IoT. Protected agriculture is a mode of highly efficient development of modern agriculture that uses artificial techniques to change climatic factors such as temperature, to create environmental conditions suitable for the growth of animals and plants. This review aims to gain insight into the state-of-the-art of IoT applications in protected agriculture and to identify the system structure and key technologies. Therefore, we completed a systematic literature review of IoT research and deployments in protected agriculture over the past 10 years and evaluated the contributions made by different academicians and organizations. Selected references were clustered into three application domains corresponding to plant management, animal farming and food/agricultural product supply traceability. Furthermore, we discussed the challenges along with future research prospects, to help new researchers of this domain understand the current research progress of IoT in protected agriculture and to propose more novel and innovative ideas in the future.


Assuntos
Agricultura/tendências , Redes de Comunicação de Computadores , Abastecimento de Alimentos , Internet/tendências , Cidades , Humanos , Tecnologia sem Fio
10.
Anal Chim Acta ; 1033: 185-192, 2018 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-30172325

RESUMO

An ultrasensitive electrochemical aptasensor for kanamycin (KAN) detection was constructed with a dual-signal amplification strategy. The aptasensor achieved greatly amplified sensitivity due to the excellent electrical conductivity of the ordered mesoporous carbon-chitosan (OMC-CS)/gold nanoparticles-streptavidin (AuNPs-SA) and DNA2 labelled with ferrocene (Fc-DNA2). The AuNPs-SA was used to immobilize the DNA strand (biotin labelled) with the biotin-streptavidin system. The DNA2 strand containing the KAN aptamer was labelled with ferrocene to increase the current signal on the electrode surface when bound to KAN. Some factors that affect the performance of the aptasensor were optimized, and the proposed aptasensor provided a wide linear range from 1 × 10-10 M to 4 × 10-6 M, with a detection limit as low as 35.69 pM for KAN under the optimized conditions. This aptasensor had satisfactory electrochemical performance with good stability, sensitivity and reproducibility. Additionally, it also displayed a good specificity for KAN without interference from competitive analogues. Furthermore, the constructed aptasensor was successfully used to detect KAN in a real milk sample. The proposed method for KAN detection has great potential for the detection of other antibiotics.


Assuntos
Aptâmeros de Nucleotídeos , DNA/química , Técnicas Eletroquímicas , Canamicina/análise , Animais , Carbono/química , Bovinos , Quitosana/química , Compostos Ferrosos/química , Ouro/química , Nanopartículas Metálicas/química , Metalocenos/química , Leite/química , Tamanho da Partícula , Porosidade , Estreptavidina/química , Propriedades de Superfície
11.
Biosens Bioelectron ; 115: 7-13, 2018 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-29783082

RESUMO

A dual-target electrochemical aptasensor was developed for the simultaneous detection of multiple antibiotics based on metal ions as signal tracers and nanocomposites as signal amplification strategy. Metal ions such as Cd2+ and Pb2+ could generate distinct differential pulse voltammetry (DPV) peaks. When targets were present, kanamycin (KAN) and streptomycin (STR) as models, the KAN aptamer (KAP) and STR aptamer (STP) were released from their complementary strands, with more change of Cd2+ and Pb2+ corresponding to peak currents. At the same time, complementary strand of KAP (cKAP) and STP (cSTP) were linked with the poly (A) structure (cSTP-PolyA-cKAP) to increase their conformational freedom. Graphitized multi-walled carbon nanotubes (MWCNTGr) and carbon nanofibers-gold nanoparticles (CNFs-AuNPs) as a biosensor platform enhanced the surface area to capture a large amount of cSTP-PolyA-cKAP, thus amplifying the detection response. Under the optimal conditions, the aptasensor could detect KAN and STR as low as 74.50 pM and 36.45 pM respectively with the range from 0.1 to 100 nM and exhibited excellent selectively. Moreover, this aptasensor showed promising applications for the detection of other analytes by changing corresponding aptamers.


Assuntos
Antibacterianos/isolamento & purificação , Técnicas Biossensoriais , Nanopartículas Metálicas/química , Leite/química , Animais , Antibacterianos/química , Aptâmeros de Nucleotídeos/química , Bovinos , Técnicas Eletroquímicas , Íons/química , Limite de Detecção , Metais , Nanotubos de Carbono/química
12.
Sci Rep ; 7(1): 14729, 2017 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-29116241

RESUMO

A sensitive and efficient ratiometric electrochemical aptasensor was designed for tetracycline (TET) detection in milk. The ratiometric electrochemical aptasensor was constructed by integrating two aptasensors termed as aptasensor 1 and aptasensor 2. The aptasensor 1 was fabricated that based on ferrocene (Fc) and gold nanoparticles (AuNPs) nanocomposite. Meanwhile, the aptasensor 2 was prepared that based on carbon nanofibers (CNFs) and AuNPs nanocomposite. TET-aptamer was immobilized effectively onto screen-printed carbon electrodes (SPCEs) surface through forming Au-S bond between AuNPs and thiol of aptamer at 5' end to construct the aptasensor 1 and aptasensor 2. And their detection results were calculated by ratio. Thus, the proposed ratiometric aptasensor solved the problem of low accuracy and large differences between batches. Under the optimized conditions, the TET was detected by differential pulse voltammetry (DPV). Taken advantage of ratio calculation, the as-prepared ratiometric aptasensor could detect TET quantitatively in the range of 10-8-10-3gL-1, with a detection limit of 3.3 × 10-7gL-1. Moreover, its applicability to TET-contaminated real samples (milk) showed an excellent agreement with the values determined by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-ESI-MS/MS). With high sensitivity, accuracy and reliability, the developed ratiometric aptasensor held a great potential in TET detection for food safety.


Assuntos
Antibacterianos/análise , Técnicas Biossensoriais , Carbono/química , Resíduos de Drogas/análise , Técnicas Eletroquímicas/instrumentação , Compostos Ferrosos/química , Metalocenos/química , Leite/química , Nanofibras/química , Tetraciclina/análise , Animais , Cromatografia Líquida de Alta Pressão/métodos , Eletrodos , Inocuidade dos Alimentos , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray/métodos
13.
Bioprocess Biosyst Eng ; 40(9): 1419-1425, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28717833

RESUMO

In this study an impedance aptasensor was designed for sensitive, selective, and fast detection of tetracycline (TET) based on an interdigital array microelectrode (IDAM). The IDAM was integrated with impedance detection to miniaturize the conventional electrodes, enhance the sensitivity, shorten the detection time, and minimize interfering effects of non-target analytes in the solution. Due to their excellent conductivity, good biocompatibility, the multi-walled carbon nanotubes (MWCNTs) were used to modify the IDAM to immobilize TET aptamer effectively. The proposed aptasensor produced a sensitive impedance change which was characterized by the electrochemical impedance spectroscopy (EIS). With the addition of TET, the formation of TET-aptamer complex on the surface of MWCNTs modified electrode resulted in an increase of electron transfer resistance (R et). The change of R et depends on the concentration of TET, which is applied for the quantification of TET. A wide linear range was obtained from 10-9 to 10-3 M. The linear regression equation was y(ΔR) = 21.310 × x(LogC) (M) + 217.25. It was successfully applied to detect TET in real milk samples.


Assuntos
Espectroscopia Dielétrica/métodos , Nanotubos de Carbono/química , Tetraciclina/análise , Espectroscopia Dielétrica/instrumentação , Microeletrodos
14.
Bioprocess Biosyst Eng ; 38(8): 1455-68, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25801002

RESUMO

A sensitive electrochemical immunosensor based on NiAl-layered double hydroxide/graphene nanocomposites (NiAl-LDH/G) and hollow gold nanospheres (HGNs) was proposed for chlorpyrifos detection. The NiAl-LDH/G was prepared using a conventional coprecipitation process and reduction of the supporting graphene oxide. Subsequently, the nanocomposites were dispersed with chitosan (CS). The NiAl-LDH/G possessed good electrochemical behavior and high binding affinity to the electrode. The high surface areas of HGNs and the vast aminos and hydroxyls of CS provided a platform for the covalently crosslinking of antibody. Under optimal conditions, the immunosensor exhibited a wide linear range from 5 to 150 µg/mL and from 150 to 2 µg/mL, with a detection limit of 0.052 ng/mL. The detection results showed good agreement with standard gas chromatography method. The constructed immunosensor exhibited good reproducibility, high specificity, acceptable stability and regeneration performance, which provided a new promising tool for chlorpyrifos detection in real samples.


Assuntos
Hidróxido de Alumínio/química , Técnicas Biossensoriais/métodos , Ouro/química , Grafite/química , Hidróxidos/química , Nanocompostos/química , Nanosferas/química , Níquel/química , Técnicas Eletroquímicas/métodos
15.
Bioprocess Biosyst Eng ; 38(2): 315-21, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25147124

RESUMO

A sensitive amperometric acetylcholinesterase (AChE) biosensor was developed based on the nanocomposite of multi-walled carbon nanotubes (MWCNTs), tin oxide (SnO2) nanoparticles and chitosan (CHIT). Acetylcholinesterase (AChE) and Nafion were immobilized onto the nanocomposite film to prepare AChE biosensor for pesticide residues detection. The morphologies and electrochemistry properties of the surface modification were investigated using cyclic voltammetry, differential pulse voltammetry, and scanning electron microscopy, respectively. Compared with individual MWCNTs-CHIT, SnO2-CHIT and bare gold electrode, this nanocomposite showed the most obvious electrochemical signal in the presence of [Fe(CN)6](3-/4-) as a redox couple. Incorporating MWCNTs and SnO2 into 0.2% CHIT solution can promote electron transfer, enhance the electrochemical response, and improve the microarchitecture of the electrode surface. All variables involved in the preparation process and analytical performance of the biosensor were optimized. Under optimized conditions, the AChE biosensor exhibited a wide linear range from 0.05 to 1.0 × 10(5 )µg/L and with a detection limit for chlorpyrifos was 0.05 µg/L. Based on the inhibition of pesticides on the AChE activity, using chlorpyrifos as model pesticide, the proposed biosensor exhibited a wide range, low detection limit, good reproducibility, and high stability. Using cabbages, lettuces, leeks, and pakchois as model samples, acceptable recovery of 98.7-105.2% was obtained. The proposed method was proven to be a feasible quantitative method for chlorpyrifos analysis, which may open a new door ultrasensitive detection of chlorpyrifos residues in vegetables and fruits.


Assuntos
Acetilcolinesterase/química , Técnicas Biossensoriais/instrumentação , Quitosana/química , Clorpirifos/análise , Nanocompostos/química , Compostos de Estanho/química , Acetilcolinesterase/análise , Clorpirifos/química , Inibidores da Colinesterase/análise , Inibidores da Colinesterase/química , Condutometria/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento , Microeletrodos , Nanocompostos/ultraestrutura , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
Bioprocess Biosyst Eng ; 38(2): 307-13, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25119301

RESUMO

An electrochemical immunosensor based on interdigitated array microelectrodes (IDAMs) was developed for sensitive, specific and rapid detection of chlorpyrifos. Anti-chlorpyrifos monoclonal antibodies were orientedly immobilized onto the gold microelectrode surface through protein A. Chlorpyrifos were then captured by the immobilized antibody, resulting in an impedance change in the IDAMs surface. Electrochemical impedance spectroscopy was used in conjunction with the fabricated sensor to detect chlorpyrifos. Under optimum conditions, the impedance value change of chlorpyrifos was proportional to its concentrations in the range of 10(0)-10(5) ng/mL. The detection limit was found to be 0.014 ng/mL for chlorpyrifos. The proposed chlorpyrifos immunosensor could be used as a screening method in pesticide determination for the analysis of environmental, agricultural and pharmaceutical samples due to its rapidity, sensitivity and low cost.


Assuntos
Clorpirifos/análise , Condutometria/instrumentação , Imunoensaio/instrumentação , Análise em Microsséries/instrumentação , Microeletrodos , Anticorpos Monoclonais/imunologia , Técnicas Biossensoriais/instrumentação , Clorpirifos/imunologia , Desenho de Equipamento , Análise de Falha de Equipamento , Inseticidas/análise , Inseticidas/imunologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
17.
Enzyme Microb Technol ; 58-59: 8-13, 2014 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-24731819

RESUMO

In this study, a novel acetylcholinesterase-based biosensor was fabricated. Acetylcholinesterase (AChE) was immobilized onto a glassy carbon electrode (GCE) with the aid of Cu-Mg-Al calcined layered double hydroxide (CLDH). CLDH can provide a bigger effective surface area for AChE loading, which could improve the precision and stability of AChE biosensor. However, the poor electroconductibility of CLDHs could lead to the low sensitivity of AChE biosensor. In order to effectively compensate the disadvantages of CLDHs, graphene-gold nanocomposites were used for improving the electron transfer rate. Thus, the graphene-gold nanocomposite (GN-AuNPs) was firstly modified onto the GCE, and then the prepared CLDH-AChE composite was immobilized onto the modified GCE to construct a sensitive AChE biosensor for pesticides detection. Relevant parameters were studied in detail and optimized, including the pH of the acetylthiocholine chloride (ATCl) solution, the amount of AChE immobilized on the biosensor and the inhibition time governing the analytical performance of the biosensor. The biosensor detected chlorpyrifos at concentrations ranging from 0.05 to 150µg/L. The detection limit for chlorpyrifos was 0.05µg/L.


Assuntos
Acetilcolinesterase , Técnicas Biossensoriais , Clorpirifos/análise , Inibidores da Colinesterase/análise , Técnicas Eletroquímicas/instrumentação , Enzimas Imobilizadas , Contaminação de Alimentos/análise , Nanocompostos , Resíduos de Praguicidas/análise , Adsorção , Silicatos de Alumínio , Ânions , Argila , Coloides , Eletrodos , Determinação de Ponto Final , Desenho de Equipamento , Metais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Propriedades de Superfície , Verduras/química
18.
Bioprocess Biosyst Eng ; 37(10): 1929-34, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24770986

RESUMO

In this study, an acetylcholinesterase (AChE) biosensor with superior accuracy and sensitivity was successfully developed based on interdigitated array microelectrodes (IAMs). IAMs have a series of parallel microband electrodes with alternating microbands connected together. Chitosan was used as the enzyme immobilization material, and AChE was used as the model enzyme for carbaryl detection to fabricate AChE biosensor. Electrochemical impedance spectroscopy was used in conjunction with the fabricated biosensor to detect pesticide residues. Based on the inhibition of pesticides on the AChE activity, using carbaryl as model compounds, the biosensor exhibited a wide range, low detection limit, and high stability. Moreover, the biosensor can also be used as a new promising tool for pesticide residue analysis.


Assuntos
Acetilcolinesterase/metabolismo , Técnicas Biossensoriais , Carbaril/análise , Inibidores da Colinesterase/análise , Microeletrodos , Limite de Detecção , Espectrofotometria Ultravioleta
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