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1.
Anal Chim Acta ; 1177: 338787, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34482893

RESUMO

The detection of glucose in human blood is of great importance in the diagnosis and prevention of diabetes. In this work, we fabricated a novel electrochemical non-enzymatic glucose sensor, NiCo-LDH nanoflake arrays-supported Au nanoparticles on copper foam (NiCo-LDH@ Au/Cu) by galvanic replacement and electrodeposition methods. Owing to the synergistic effect of three-dimensional (3D) architecture of Cu foam, high electrocatalytic activity of Au nanoparticles and NiCo-LDH nanoflake arrays, the NiCo-LDH@Au/Cu electrode exhibits excellent electrocatalytic ability for glucose oxidation in NaOH solution. Under optimized conditions, the NiCo-LDH@Au/Cu electrode shows excellent activity with a linear range from 0.5 to 3000 µM at the potential of 0.50 V (vs. Ag/AgCl), a low detection limit of 0.23 µM (S/N = 3), an ultra-prompt response time of 0.5 s, and a high sensitivity of 23100 µA mM-1 cm-2, as well as good selectivity and stability. Furthermore, the as-fabricated non-enzymatic glucose sensor was successfully applied to the glucose detection in human serum as a promising candidate in the development of electrochemical non-enzymatic glucose sensor.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Cobre , Técnicas Eletroquímicas , Glucose , Ouro , Humanos
2.
J Hazard Mater ; 416: 125895, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492833

RESUMO

Ce-MOF/CNTs nanocomposites were prepared by a simple method and post-treated with NaOH/H2O2 mixed solution. The morphology and structure of the treated samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that the post treatment induces the Ce-MOF morphological changing from rod-like structure into particles, which are covered on the surface of CNTs. XPS demonstrates that there are two-valence (TV) of Ce3+/Ce4+ in the post-treated Ce-MOF/CNTs (TV) composite. The electrochemical behaviors of nanocomposite were also investigated on electrochemical work station. By utilization of the good electrical conductivity of CNT, the two-valence of Ce and the high surface area of MOF, the nanocomposites were used to fabricate the electrochemical sensor for the simultaneous electrochemical detection of hydroquinone (HQ) and catechol (CC). Compared to the Ce-MOF/CNTs/GCE, the post-treated Ce-MOF (TV)/CNTs/GCE exhibited two well-defined peaks for the electrochemical oxidation of HQ and CC. The linear ranges responding to HQ and CC are 10~100 µM and 5~50 µM respectively.


Assuntos
Nanocompostos , Nanotubos de Carbono , Catecóis , Técnicas Eletroquímicas , Peróxido de Hidrogênio , Hidroquinonas
3.
Talanta ; 235: 122694, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517578

RESUMO

This work reports a simple strategy for Candida auris genomic DNA (gDNA) detection, a multi-resistant fungus associated with nosocomial outbreaks in healthcare settings, presenting high mortality and morbidity rates. The platform was developed using gold electrode sensitized with specific DNA capture probe and ninhydrin as a novel DNA hybridization indicator. The genosensor was able to detect C. auris in urine sample by differential pulse voltammetry and electrochemical impedance spectroscopy. The biosensor's analytical performance was evaluated by differential pulse voltammetry, detecting up to 4.5 pg µL-1 of C. auris gDNA in urine (1:10, V/V). Moreover, the genosensor was reused eight times with no loss in the current signal response. The genosensor showed selectivity and stability, maintaining 100% of its response up to 80 days of storage. In order to analyze interactions of single and double-stranded DNA with ninhydrin, SEM, AFM and molecular dynamics studies followed by docking simulations were performed. Theoretical calculations showed ninhydrin interactions more favorably with dsDNA in an A-T rich binding pocket rather than with the ssDNA. Therefore, the proposed system is a promising electrochemical detection device towards a more accurate detection of C. auris gDNA in biological samples.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Candida/genética , DNA , Ninidrina
4.
Talanta ; 235: 122717, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517585

RESUMO

Groundnut bud necrosis orthotospovirus (GBNV) is one of the causative plant viruses responsible for the outbreak of many viral epidemics in food crops across India and other south-Asian countries. Its management is a major challenge due to fast vector transmission, and the non-availability of appropriate agrochemical treatment. The timely detection of GBNV becomes indispensable for the effective management of viral infection and the periodic monitoring of plant health. We report the fabrication of graphene oxide (GO) based electrochemical immunosensor for the rapid and sensitive detection of GBNV. The immunoelectrode is prepared by depositing GO onto indium-tin oxide (ITO) coated glass substrates and functionalized by anti-GBNV antibodies using N-ethyl-N'-(3- dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide (EDC-NHS) conjugation chemistry. The response measurements of the immunoelectrodes revealed a sensitivity of 221 ± 1 µA µg-1 mL-1(n = 3) and limit of detection (LOD) of 5.7 ± 0.7 ng mL-1(n = 3) for the standard concentrations of GBNV antigen. Further, the GBNV detection was carried out in infected leaf extracts of three different host plants i.e., Tomato, Cowpea, and N. benthamiana, and the results have been compared with the conventionally used direct antigen coated enzyme-linked immunosorbent assay (DAC-ELISA) technique. The comparable results obtained for the detection of GBNV in infected plants using electrochemical immunosensing and DAC-ELISA techniques advocated the immense potential of GO based immunosensor as a point-of-care sensing device that is poised to overcome the limitations of the traditional methods of virus detection in field conditions and may transform the diagnostics in agriculture.


Assuntos
Técnicas Biossensoriais , Grafite , Tospovirus , Produtos Agrícolas , Técnicas Eletroquímicas , Humanos , Imunoensaio , Necrose , Doenças das Plantas
5.
Talanta ; 235: 122732, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517600

RESUMO

A novel competitive mechanism electrochemiluminescence (ECL) immunoassay based on resonance energy transfer was used to detect florfenicol for the first time. In this work, CeO2@TiO2 nanocomposite, which was used as a donor, was prepared in sol-gel method and the effective band gap of TiO2 could be reduced by CeO2, which promoted the ECL emission of TiO2 and made the ECL performance of the donor more outstanding. The absorption spectrum of Cu2S and the ECL emission spectrum of the donor could be highly matched, which ensured the occurrence of electrochemiluminescence resonance energy transfer (ECL-RET). In addition, the snowflake-like structure of cuprous sulfide could load more antibodies. It is worth mentioning that as far as we know, there have been no reports of this material as an ECL receptor before. Furthermore, the ECL-RET system based on this has shown excellent performance in the detection of florfenicol. The proposed immunoassay showed satisfactory sensitivity with a wide linear range from 0.001 to 1000 ng mL-1 and a low detection limit (0.3 pg mL-1). Due to the remarkable quenching effect and simple assembly process, the immunoassay is of great practical significance and has reference value for the detection of florfenicol or other biological small molecules.


Assuntos
Técnicas Biossensoriais , Ouro , Técnicas Eletroquímicas , Transferência de Energia , Imunoensaio , Limite de Detecção , Medições Luminescentes , Tianfenicol/análogos & derivados
6.
Talanta ; 235: 122734, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517603

RESUMO

Polyphenols are bioactive substances of vegetal origin with a significant impact on human health. The assessment of polyphenol intake and excretion is therefore important. In this work, a new electrochemical approach based on molecularly imprinted polymer extraction and preconcentration, combined with a disposable carbon screen-printed sensor and adsorptive transfer differential pulse voltammetry detection has been proposed for quantifying of 4-hydroxyphenylacetic acid (4-HPA), which is a biomarker of flavan-3-ols intake, and other phenolic acids. The simple experimental performance has allowed the rapid data collection with relevant information about the profile of catabolites extracted. The method was validated over a concentration range of 10-200 mg L-1, R2 > 0.999. In the optimized conditions, the recovery value was 94% with RSD 8%. The limits of detection and quantification were 2.38 mg L-1 and 7.21 mg L-1, respectively. The method was validated by means of a chromatographic method, being the differences between the values of the 4-HPA concentrations obtained by both methods under 1%. The proposed method showed high recoveries, low detection limit, and good accuracy, providing a fast, reliable, and cheap procedure to quantify phenolic metabolites in urine, and representing therefore a good and interesting alternative method. Also, the procedure offers other advantages, including the miniaturization, the low use of organic solvents, the ability to analyse small volumes of samples, in situ analysis and simple instrumentation requirement.


Assuntos
Impressão Molecular , Técnicas Eletroquímicas , Eletrodos , Flavonoides , Humanos , Limite de Detecção , Extração em Fase Sólida , Solventes
7.
Talanta ; 235: 122736, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517604

RESUMO

Methods to improve the sensitivity of electrochemical sensors based on catalytic reactions generally require adscititious or pre-modified catalysts, which make the sensitive detection of sensors extremely challenging. This is because the activity of the catalyst is susceptible to the storage and modification process, such as aggregation during storage or loss of active sites during multi-step modification, which impairs the performance of the sensor. To solve this thorny issue, a novel electrochemical sensor based on a process-formed laccase-like catalyst was constructed for sensitive detection of tumor markers. Cu2+-polydopamine (CuPDA) combined with antibody (Ab2) were employed as copper-containing immunoprobe, which released Cu(Ⅱ) ions under acidic stimulation. Cu(Ⅱ) ions coordinate with the self-assembly cationic diphenylalanine-glutaraldehyde nanospheres (CDPGA) to form a laccase-like catalyst, which had stronger catalytic activity than laccase. The freshly formed catalyst was immediately used to degrade the polyhydroquinone-reduced graphene oxide (PHQ-rGO) composite, resulting in a significant reduction in the current signal. The PHQ-rGO composite plays dual roles of signal substance and substrate on the sensing interface. The proposed electrochemical sensor demonstrated wide linearity for the determination of a model analyte, human epididymis protein 4 (HE4), from 1 pg mL-1 to 100 ng mL-1, and the detection limit was as low as 0.302 pg mL-1 (S/N = 3), which had good consistency with that of electrochemiluminescence method. This process-formed catalyst approach will have potential reference significance for the construction of other sensors.


Assuntos
Técnicas Eletroquímicas , Grafite , Biomarcadores Tumorais , Catálise , Cobre , Humanos , Lacase
8.
Talanta ; 235: 122744, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517612

RESUMO

The detection of trace tumor-related serum miRNA biomarkers is in great demand for the early diagnosis of cancer. Herein, for the first time, an electrochemical sensing platform based on atom transfer radical polymerization (ATRP) signal amplification strategy for ultrasensitive determination of the breast and prostate cancer marker miRNA-141 has been developed. The hairpin DNAs were immobilized on the benzoic acid modified electrode to capture the target miRNA-141, the recognition of miRNA-141 released thiol groups on the end of probes, followed by the association of ATRP initiators modified gold nanoparticles with thiol groups, and then triggered the polymerization on electrode surface, causing a great number of ferrocene (Fc) signal molecules grafted on the sensor interface. As a result, the electrochemical signal intensity of signal molecule has been greatly increased. The proposed biosensor has a linear range from 10 pM to 10 aM with a detection limit of 3.23 aM for miRNA-141, opening a new and promising path for ultrasensitive analysis of tumor-related miRNAs.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , MicroRNAs , Técnicas Eletroquímicas , Ouro , Humanos , Limite de Detecção , Masculino , Polimerização
9.
Talanta ; 235: 122751, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517619

RESUMO

Developing a convenient and accurate method for the determination of acetaminophen (APAP) content is very vital, and ferrocene (Fc) based nanocomposites coupled with polyoxometalates (POMs) as electrochemical sensor is a promising approach to address the issues. Herein, a new ternary nanocomposite of Fc based carbon nanomaterials (Fc-rGO) with PMo12 (Fc-rGO/PMo12, rGFP-n) was successfully fabricated, and the electrochemical activities and APAP detection of rGFP-n as electro-active materials were systematically investigated, and results of the differential pulse voltammetry (DPV) and electro-active surface area (0.0332 cm2) show that rGFP-1 is an excellent electrochemical sensor for APAP, and the proportion of Fc in rGFP-n can affect the charge transfer between APAP and rGFP. Under the optimal experimental conditions, rGFP-1 can be used to detect APAP with the limit of detection (LOD) of 13.27 nM (S/N = 3), the sensitivity of 36.81µA⋅µM-1cm-2, and the detection range from 1×10-6 to 1×10-3M, meeting the lowest plasma concentration of APAP (1.3 mM).


Assuntos
Acetaminofen , Nanocompostos , Técnicas Eletroquímicas , Grafite , Metalocenos , Compostos de Tungstênio
10.
Talanta ; 235: 122753, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517621

RESUMO

The design and fabrication of high sensitive and selective biosensing platforms areessential goals to precisely recognize biomaterials in biological assays. In particular, determination of adenosine triphosphate (ATP) as the main energy currency of the cells and one of the most important biomolecules in living organisms is a pressing need in advanced biological detection. Recently, aptamer-based biosensors are introduced as a new direct strategy in which the aptamers (Apts) directly bind to the different targets and detect them on the basis of conformational changes and physical interactions. They can also be conjugated to optical and electronic probes such as quantum dot (QD) nanomaterials and provide unique QD aptasensing platforms. Currently, these Apt-based biosensors with excellent recognition features have attracted extensive attention due to the high specificity, rapid response and facile construction. Therefore, in this review article, recent achievements and advances in aptasensing detection of ATP based on different detection methods and types of QDs are discussed. In this regard, the optical and electrochemical aptasensors have been categorized based on detection methods; fluorescence (FL), electrochemiluminescence (ECL) and photoelectrochemical (PEC) and they have been also divided to two main groups based on QDs; metal-based (M-based) and carbon-based (C-based) materials. Then, their advantages and limitations have been highlighted, compared and discussed in detail.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Pontos Quânticos , Trifosfato de Adenosina , Técnicas Eletroquímicas , Oligonucleotídeos
11.
Talanta ; 235: 122782, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517640

RESUMO

Previous 17ß-estradiol sensors required expensive reagents or complicated fabrication of sensing probes. In this work, a cheap, simple, and reusable electrochemical sensor based on commercially available polyaniline (PANI) and carbon dots (CDs) synthesized from iota-carrageenan was developed for the sensitive detection of 17ß-estradiol. The sensor was simply prepared by drop-casting CDs/PANI composite on a glassy carbon electrode (GCE) using poly(vinylidene fluoride) as a binder. With synergistic contributions from both CDs and PANI, the CDs-PANI/GCE was much more electrochemically stable than the CDs/GCE or PANI/GCE. The CDs-PANI/GCE was sensitive to 17ß-estradiol across a linear range from 0.001 to 100 µmol L-1 with a detection limit of 43 nmol L-1. The electrochemical measurement can be performed in 2 min and the probe can be reused for several hundred times. The CDs-PANI/GCE was selective towards 17ß-estradiol against several interferences and gave excellent recovery between 94.4 and 103.7 % from real sample analysis. From intensive investigation on electron transfer process and energy levels, the oxidation reaction of 17ß-estradiol occurred on the surface of CDs-PANI/GCE via favorable energy levels and dominantly surface adsorption process through π-π stacking and hydrogen bonding between 17ß-estradiol and CDs/PANI. Such unique interfacial interactions also resulted in the synergistically enhanced electrochemical stability of the modified electrode.


Assuntos
Carbono , Técnicas Eletroquímicas , Compostos de Anilina , Eletrodos , Estradiol
12.
Talanta ; 235: 122790, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517648

RESUMO

Abnormal glycosylation of exosomal proteins is related to many diseases. However, there is still a lack of convenient and easy methods for the determination of exosomal glycoproteins. In this work, a ratiometric electrochemical sensor based on the recognition of glycoproteins by boronic acid and core-shell nanoparticles of silica-silver (SiO2@Ag) amplified signals was developed for the highly sensitive detection of exosomal glycoproteins. The CD63 aptamer-SiO2-N-(2-((2-aminoethyl)disulfanyl)ethyl) ferrocene carboxamide (FcNHSSNH2) probe was first connected to graphene oxide-cucurbit [7] (GO-CB [7]) modified GCE through host-guest recognition. The CD63 aptamer was employed for the specific capture of exosomes, and the FcNHSSNH2 molecule was used as the internal reference signal of the sensor. The mercaptophenylboronic acid (MPBA) of MPBA-SiO2@Ag probe was used for the identification of exosomes surface glycoproteins. SiO2 nanoparticle has a large specific surface area, which can load a large amount of silver nanoparticles (AgNPs) for electrochemical signal amplification. The results were expressed as the current ratio of AgNPs and FcNHSSNH2. The introduction of the internal reference molecule FcNHSSNH2 could effectively reduce the measurement error caused by the different DNA density of the substrate, and further improve the sensitivity and accuracy of the detection. Under the optimal experimental conditions, this sensor allowed the sensitive detection of exosomal glycoproteins in the range of 4.2 × 102 to 4.2 × 108 particles/µL with a limit of detection (LOD) of 368 particles/µL. Furthermore, the ratiometric electrochemical sensor could be employed for the detection of exosomal glycoproteins in human serum samples, which has a good clinical application prospect.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Técnicas Eletroquímicas , Glicoproteínas , Humanos , Limite de Detecção , Dióxido de Silício , Prata
13.
Talanta ; 235: 122803, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517661

RESUMO

An electrochemical biosensor for highly sensitive detection of tobacco mosaic virus (TMV) RNA (tRNA) based on click chemistry and photoinduced atom transfer radical polymerization (photoATRP) is developed for the first time. Herein, tRNA is recognized and captured by hairpin DNA immobilized on the gold electrode surface by Au-S self-assembly. Propyl 2-bromoisobutyrate (PBIB), a photoATRP initiator containing an alkyne group, is conjugated to the azide group of hairpin DNA via a Cu(I)-catalyzed azidoalkyl cyclization reaction (CuAAC). Under the irradiation of 470 nm blue light, photoATRP is activated by the photoredox catalyst (eosin Y, EY), resulting in the formation of a large number of electroactive probes (ferrocenylmethyl methacrylate, FMMA), which significantly amplifies the signal. Under the optimal experimental parameters, the strategy has a wide linear detection (0.1 pM-10 nM) (R2 = 0.995) with a limit of detection (LOD) as low as 3.5 fM. In addition, the biosensor also exhibited good selectivity for mismatched bases, excellent stability and reproducibility. Moreover, satisfactory result was achieved when the biosensor was applied to the detection of tRNA from healthy rehmannia total RNA extracts, which demonstrates the great potential of the method in the practical detection of TMV.


Assuntos
Técnicas Biossensoriais , Vírus do Mosaico do Tabaco , Química Click , Técnicas Eletroquímicas , Limite de Detecção , Polimerização , RNA , Reprodutibilidade dos Testes
14.
Nanoscale ; 13(34): 14316-14329, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34477715

RESUMO

Non-invasive liquid biopsies offer hope for a rapid, risk-free, real-time glimpse into cancer diagnostics. Recently, hydrogen peroxide (H2O2) was identified as a cancer biomarker due to its continued release from cancer cells compared to normal cells. The precise monitoring and quantification of H2O2 are hindered by its low concentration and the limit of detection (LOD) in traditional sensing methods. Plasmon-assisted electrochemical sensors with their high sensitivity and low LOD make a suitable candidate for effective detection of H2O2, yet their electrical properties need to be improved. Here, we propose a new nanostructured microfluidic device for ultrasensitive, quantitative detection of H2O2 released from cancer cells in a portable fashion. The fluidic device features a series of self-organized gold nanocavities, enhanced with graphene nanosheets having optoelectrical properties, which facilitate the plasmon-assisted electrochemical detection of H2O2 released from human cells. Remarkably, the device can successfully measure the released H2O2 from breast cancer (MCF-7) and prostate cancer (PC3) cells in human plasma. Briefly, direct amperometric detection of H2O2 under simulated visible light illumination showed a superb LOD of 1 pM in a linear range of 1 pM-10 µM. We thoroughly studied the formation of self-organized plasmonic nanocavities on gold electrodes via surface and photo-electrochemical characterization techniques. In addition, the finite-difference time domain (FDTD) simulation of the electric field demonstrates the intensity of charge distribution at the nanocavity structure edges under visible light illumination. The superb LOD of the proposed electrode combining gold plasmonic nanocavities and graphene sheets paves the way for the development of non-invasive plasmon-assisted electrochemical sensors that can effectively detect low concentrations of H2O2 released from cancer cells.


Assuntos
Grafite , Neoplasias , Técnicas Eletroquímicas , Ouro , Humanos , Peróxido de Hidrogênio , Dispositivos Lab-On-A-Chip , Neoplasias/diagnóstico
15.
Nanoscale ; 13(30): 13014-13023, 2021 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-34477784

RESUMO

A facile one-pot precipitation method was employed to prepare a petal-shaped hybrid under mild conditions. The hybrid is composed of urate oxidase (UOx) encapsulated into a zeolite-like metal-organic framework (MOF) with the doping of a hollow gold nanocage (AuNC). As one of the MOF-enzyme composites, a UOx@MOF(AuNC) hybrid with the features of artificial nanoenzymes was developed as a novel dual-channel biosensing platform for fluorescence (FL) and electrochemical detection of uric acid (UA). As for FL biosensing, enzymatic catalysis of the hybrid in the presence of UA triggered tandem catalysis and oxidation reactions to cause FL quenching. UA was linearly detected in the 0.1-10 µM and 10-300 µM ranges, with the limit of detection (LOD) of 20 nM. As for electrochemical biosensing, the hybrid was dropped on a glassy carbon electrode (GCE) surface to construct a hybrid/GCE platform. Based on the redox reaction of UA on the platform surface, UA was linearly detected in the 0.05-55 µM range, with a LOD of 15 nM. Experimental results confirmed that the hybrid-based dual-channel biosensing platform enabled selective and sensitive responses to UA over potential interferents. The platform has an excellent detection capability in physiological samples. The dual-channel biosensing platform facilitates the exploration of new bioanalysis techniques for early clinical diagnosis of diseases.


Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas , Catálise , Técnicas Eletroquímicas , Eletrodos , Ouro , Limite de Detecção , Urato Oxidase
16.
Analyst ; 146(18): 5528-5532, 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34515710

RESUMO

Conventional photoelectrochemical (PEC) analysis mostly utilizes photoactive material modified planar indium tin oxides (ITOs) to obtain photocurrent responses for the measurement of analytes in solution. In this work, a CdS quantum dot (QD) modified nanopipette was prepared for the PEC analysis of the alkaline phosphatase (ALP) activity in single MCF-7 cells. The nanopipette was filled with ascorbic acid 2-phosphate (AAP) that was egressed outside the nanopipette by electrochemical pumping. Next, AAP was catalyzed by ALP to generate ascorbic acid (AA), which is an efficient electron donor for CdS QDs under illumination. Based on the result that the nanopipette showed a linear photocurrent response to AA, a nearly linear correlation between the photocurrent and the activity of ALP was established. Accordingly, using these CdS QD modified nanopipettes, the ALP activity in single MCF-7 cells was determined to be 0.12 U mL-1 by PEC analysis. This work does not expand the application of PEC bioanalysis, but offers a new strategy for single cell analysis.


Assuntos
Técnicas Biossensoriais , Pontos Quânticos , Fosfatase Alcalina , Técnicas Eletroquímicas
17.
Anal Chem ; 93(36): 12367-12373, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34469106

RESUMO

Development of sensors uniting different sensing principles is in line with the concept of reliable, comprehensive, and diversified equipment construction. However, the current exploration in this field is obstructed by compromise of reaction conditions and inevitable mutual interference arising from different sensing modes. This work reported a closed bipolar electrode (c-BPE) strategy for dual-modality detection or dual-target detection. To this end, a c-BPE sensing platform installed in physically separated anode and cathode compartments was well designed and carefully optimized. If luminol was present in the anode section and Prussian blue (PB) was at the cathode part, single stimulation could realize electrochemiluminescence (ECL) from luminol at the anode and conversion of PB to Prussian white (PW) at the cathode. The latter reaction helped elevate the ECL signal and also prepared for colorimetric detection as color change from PW to PB under the trigger of oxidant (like H2O2) was used to track the content of the oxidant. Thus, dual signals were obtained for dual-modality detection of single target or the detection of different targets was realized at different poles. Detection of glucose was carried out to validate the application for dual-modality detection, while VLDL/AChE and NADH/H2O2 assays illustrated the potential of dual-target detection. The proposed platform possesses outstanding sensing performance including selectivity, repeatability, long-term stability, accuracy, and so forth. This work implements a breakthrough in designing dual-mode sensors and is expected to present a rational basis for development of a diversified sensing platform.


Assuntos
Técnicas Biossensoriais , Colorimetria , Técnicas Eletroquímicas , Eletrodos , Peróxido de Hidrogênio , Medições Luminescentes
18.
J Hazard Mater ; 416: 125988, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492885

RESUMO

It is important to develop highly-active photoelectrochemical (PEC) materials and use novel sensing strategy for constructing high-PEC-performance sensors with multiplex detection abilities, owing to the simultaneous presence of multiple antibiotic residues in food. Herein, a bias-potential-based PEC aptasensor was prepared for the trace detection of dual antibiotic analytes, enrofloxacin (ENR) and ciprofloxacin (CIP), which often coexist in milk samples. Here, two materials were developed with excellent PEC performance: three-dimensional nitrogen-doped graphene-loaded copper indium disulfide (CuInS2/3DNG) and Bi3+-doped black anatase titania nanoparticles decorated with reduced graphene oxide (Bi3+/B-TiO2/rGO). By applying different bias potentials to the two materials near one ITO electrode, the cathodic current generated by CuInS2/3DNH and the anodic current generated by Bi3+/B-TiO2/rGO could be clearly distinguished without interfering with each other. Then, ENR and CIP aptamers were respectively modified onto the surface of CuInS2/3DNH and Bi3+/B-TiO2/rGO to construct a PEC aptasensor for the sensitive detection of ENR and CIP. Under optimal conditions, the proposed aptasensor exhibited wide linear ranges of ENR (0.01-10000 ng/mL) and CIP (0.01-1000 ng/mL), and relatively low detection limits of 3.3 pg/mL to ENR and CIP (S/N = 3). The aptasensor was successfully applied to the detection of ENR and CIP in milk samples.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Grafite , Animais , Ciprofloxacina , Técnicas Eletroquímicas , Enrofloxacina , Limite de Detecção , Leite
19.
J Hazard Mater ; 416: 126196, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492960

RESUMO

A Schottky junction based on Ti3C2Tx MXene sheet integrated with marigold flower-like V2O5/CuWO4 heterojunction was designed and fabricated for robust ammonia sensing by monitoring the electrical resistance changes in air and ammonia. The electron transport behavior of the sensor was investigated by electrochemical analysis, ultraviolet photoelectron spectroscopy and reflection electron energy loss spectroscopy. Besides, negative zeta potential obtained for sensor components was in consistent with surface functional groups (e.g. OH and F) observed by XPS analysis helping better understanding of the ammonia sensing mechanism. The results desirably confirmed high sensitivity, selectivity, linear range (1-160 ppm), the limit of quantification, repeatability, long-term stability, very short response time (few seconds) and low working temperature (25 °C) of the sensor. The measurements on the resistance changes of the MXene/V2O5/CuWO4-based sensor under the exposure to various types of analytes (Ammonia, Acetone, Benzene, Chloroform, DMF, Ethanol, humidity (80%), Methanol and Toluene as well as NO, NO2, H2S, SO2, CO and CH4) at different concentrations revealed that the fabricated sensor is excellently selective to ammonia with ultra-high sensitivity. Intra-day stability (7 runs a day) and long-term stability (every 10 days over 70 days) as important sensor characteristics were investigated at 51 ppm and ambient temperature, which showed very good repeatability and recoverability in both short and long periods for sensing the ammonia. Overall, MXene/V2O5/CuWO4 was shown to be cost-effective, easy to handle and suitably applicable for simple, ultrafast and extremely efficient trace ammonia detection, which could be of high interest for future exhaled breath analysis and the development of a novel noninvasive diagnostic strategy to monitor chronic kidney disease to stop a large measure of unnecessary invasive testing.


Assuntos
Amônia , Testes Respiratórios , Técnicas Eletroquímicas , Umidade , Temperatura
20.
J Hazard Mater ; 416: 126201, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492964

RESUMO

In this study, lead(II) sulfide (PbS) nanocrystals were modified on nickel(II)oxide nanosheets (NiO NSs) via the chemical bath method. Afterwards, Au nanoparticles (NPs) were also modified successfully. A photoelectrochemical (PEC) self-powered platform for detecting sarcosine with high PEC activity was constructed. The capacity of NiO NSs to be loaded with other sensitizing materials was mainly attributed to its porous structure and large specific surface area. Under optimum conditions, the constructed PEC self-powered cathodic sensor for detecting sarcosine exhibited a linear range in 5.0 × 10-8-5.0 × 10-2 mol/L with a detection limit (LOD) of 1.7 × 10-8 mol/L. The biosensor demonstrated good reproducibility, acceptable stability and high specificity, thus confirming its potential application in the detection of other similar substances.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Técnicas Eletroquímicas , Ouro , Limite de Detecção , Reprodutibilidade dos Testes , Sarcosina
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