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1.
ACS Omega ; 9(18): 20021-20029, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38737026

RESUMO

The growing requirement for real-time monitoring of health factors such as heart rate, temperature, and blood glucose levels has resulted in an increase in demand for electrochemical sensors. This study focuses on enzyme-free glucose sensors based on 2D-MoS2 nanostructures explored by simple hydrothermal route. The 2D-MoS2 nanostructures were characterized by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and XPS techniques and were immobilized at GCE to obtain MoS2-GCE interface. The fabricated interface was characterized by electrochemical impedance spectroscopy which shows less charge transfer resistance and demonstrated superior electrocatalytic properties of the modified surface. The sensing interface was applied for the detection of glucose using amperometry. The MoS2-GCE-sensing interface responded effectively as a nonenzymatic glucose sensor (NEGS) over a linearity range of 0.01-0.20 µM with a very low detection limit of 22.08 ng mL-1. This study demonstrates an easy method for developing a MoS2-GCE interface, providing a potential option for the construction of flexible and disposable nonenzymatic glucose sensors (NEGS). Moreover, the fabricated MoS2-GCE electrode precisely detected glucose molecules in real blood serum and urine samples of diabetic and nondiabetic persons. These findings suggest that 2D-MoS2 nanostructured materials show considerable promise as a possible option for hyperglycemia detection and therapy. Furthermore, the development of NEGS might create new prospects in the glucometer industry.

2.
J Colloid Interface Sci ; 669: 506-517, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38723539

RESUMO

Graphitic phase carbon nitride (g-C3N5), as a novel n-type metal-free material, is employed as a visible light-receptive catalyst because of its narrow band gap and abundant nitrogen. To overcome the low carrier mobility efficiency of g-C3N5, its modification by K ions was adopted. In addition, In2S3 was selected to couple with modified g-C3N5 to overcome the recombination of photogenerated e-/h+. As a novel photocatalytic material, it was proven to possess a high visible light absorption capacity and a strong H2O2 production ability (up to 3.89 mmol⋅L-1 in 2 h). Moreover, a S-scheme heterojunction structure was successfully constructed between the two materials, which was tested and confirmed to be successful in raising the photogenerated e-/h+ separation efficiency. Ultimately, the primary processes of photocatalytic H2O2 production were summarized by superoxide radical and rotating disc electron measurements. This research provides a fresh perspective for the synthesis of C3N5-based S-scheme heterojunction photocatalysts for producing H2O2.

3.
J Hazard Mater ; 465: 133036, 2024 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-38000286

RESUMO

A highly efficient system incorporates the real-time visualization of the two toxic molecules (H2S and N2H4) and the recognition of corresponding transforms using a fluorescent sensor. In this paper, a dual-responsive probe (QS-DNP) based on methylquinolinium-salicyaldehyde-2,4-dinitrophenyl was developed that can simultaneously detect H2S and N2H4 at two independent fluorescent channels without signal crosstalk. QS-DNP showed excellent anti-interference, high selectivity, outstanding water solubility, low LOD values (H2S: 51 nM; N2H4: 40 nM), low cytotoxicity, and mitochondrial localization properties. The 2,4-dinitrophenyl site was sensitive to H2S, and the CC bridge was reactive to N2H4, with strong fluorescence at 680 and 488 nm, respectively. The wavelength gap between these two channels is 192 nm; verify that there is no signal crosstalk throughout detection. By this means, the probe was used to simultaneously detect H2S and N2H4 in real soil samples, food samples, and living cells. The endogenous H2S and N2H4 were monitored in HeLa cells and investigated the mitochondria organelle of living cells with a positive charge on QS-DNP. Overall, all results emphasize that the QS-DNP probe is a powerful tool for the simultaneous detection of H2S and N2H4 and presents a potential new sensing approach.


Assuntos
Corantes Fluorescentes , Hidrazinas , Sulfeto de Hidrogênio , Humanos , Células HeLa , Mitocôndrias , Espectrometria de Fluorescência
5.
Sci Rep ; 13(1): 20482, 2023 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-37993482

RESUMO

In modern era, deficiency of Vitamin D3 is predominantly due to limited exposure to sunlight and UV radiation resulting from indoor lifestyles. Several studies have revealed that vitamin D deficiency can lead to chronic vascular inflammation, diabetes mellitus, hypertension, congestive left ventricular hypertrophy, and heart failure. This study introduces a green synthesis of novel bimetallic nanoporous composite, CuO/Ag using lemon extract. The synthesized nanoporous material, CuO/Ag@lemon extract was characterized using several analytical techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The CuO/Ag@lemon extract nanoparticles were immobilized on glassy carbon electrode (GCE) to prepare modified CuO/Ag@lemon extract-GCE interface. The electrocatalytic and electrochemical properties investigation was carried out on the modified electrode. using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometry for detecting of Vitamin D3. The DPV method displayed a linear response range of 0.02-22.5 µM with a detection limit of 2.62 nM, while the amperometric method showed a broader linear range of 0.25-23.25 µM with a detection limit of 2.70 nM with 82% modified electrode stability. The designed electrode exhibited a positive response to the inclusion of Vitamin D3 with electro-oxidation, reaching steady-state within 3.4 s, with 87% reproducibility within a day. The proposed method offers a rapid and sensitive platform for detection of Vitamin D3 with minimal interference from other molecules. The early diagnosis of Vitamin D3 deficiency using modified electrodes allows for early treatment, thereby preventing severe health complications.


Assuntos
Nanoporos , Reprodutibilidade dos Testes , Colecalciferol , Técnicas Eletroquímicas/métodos , Carbono/química , Eletrodos , Limite de Detecção
6.
Biosensors (Basel) ; 13(5)2023 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-37232903

RESUMO

Wide-ranging research efforts have been directed to prioritize scientific and technological inventions for healthcare monitoring. In recent years, the effective utilization of functional nanomaterials in various electroanalytical measurements realized a rapid, sensitive, and selective detection and monitoring of a wide range of biomarkers in body fluids. Owing to good biocompatibility, high organic capturing ability, strong electrocatalytic activity, and high robustness, transition metal oxide-derived nanocomposites have led to enhancements in sensing performances. The aim of the present review is to describe key advancements of transition metal oxide nanomaterials and nanocomposites-based electrochemical sensors, along with current challenges and prospects towards the development of a highly durable and reliable detection of biomarkers. Moreover, the preparation of nanomaterials, electrode fabrication, sensing mechanism, electrode-bio interface, and performance of metal oxides nanomaterials and nanocomposite-based sensor platforms will be described.


Assuntos
Nanocompostos , Elementos de Transição , Técnicas Eletroquímicas , Óxidos , Biomarcadores
7.
Anal Bioanal Chem ; 415(16): 3111-3129, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37169938

RESUMO

Pathogenic bacterial infection is one of the principal causes affecting human health and ecosystems. The accurate identification of bacteria in food and water samples is of significant interests to maintain safety and health for humans. Culture-based tests are practically tedious and may produce false-positive results, while viable but non-culturable microorganisms (NCMs) cannot be retrieved. Thus, it requires fast, reliable, and low-cost detection strategies for on-field analysis and point-of-care (POC) monitoring. The standard detection methods such as nucleic acid analysis (RT-PCR) and enzyme-linked immunosorbent assays (ELISA) are still challenging in POC practice due to their time-consuming (several hours to days) and expensive laboratory operations. The optical (surface plasmon resonance (SPR), fluorescence, and surface-enhanced Raman scattering (SERS)) and electrochemical-based detection of microbes (early stage of infective diseases) have been considered as alternative routes in the emerging world of nanostructured biosensing since they can attain a faster and concurrent screening of several pathogens in real samples. Moreover, optical and electrochemical detection strategies are opening a new route for the ability of detecting pathogens through the integration of cellphones, which is well fitted for POC analysis. This review article covers the current state of sensitive mechanistic approaches for the screening and detection of Escherichia coli O157:H7 (E. coli) pathogens in food and water samples, which can be potentially applied in clinical and environmental monitoring.


Assuntos
Técnicas Biossensoriais , Escherichia coli O157 , Humanos , Técnicas Biossensoriais/métodos , Ecossistema , Ressonância de Plasmônio de Superfície/métodos , Escherichia coli O157/química , Água , Microbiologia de Alimentos
8.
Curr Med Chem ; 2023 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-37170993

RESUMO

Detection of emergent biomolecules or biomarkers remains crucial for early diagnosis in advancing healthcare monitoring and biomedicine. The possibility for rapid detection, real-time monitoring, high sensitivity, low detection limit, good selectivity, and low cost is central, among other significant issues for advancing point-of-care diagnosis. Carbon-based nanocomposites have been employed as sensing materials for various biomarkers due to their high surface-to-volume ratio, high electrical conductivity, chemical stability, and biocompatibility. The carbon nanomaterials, such as carbon nanotubes (CNTs), graphene (GR), carbon quantum dots (CQDs), carbon fibres (CFs), and their nanocomposites have broadly integrated with numerous sensing electrode materials for the detection of biomarkers under various experimental settings. The present review includes the recent advances in the development of carbon nanomaterials-based electrochemical sensors and biosensors for biomedical applications. The preparation, electrode preparation, effective utilization of carbon-derived nanomaterials, and their sensing performances towards numerous biomarkers have been highlighted. The state-of-the-merit, challenges, and prospects for designing carbon nanocomposites-based electrochemical sensor/biosensor platforms for biomedical diagnostics have also been described.

10.
Curr Top Med Chem ; 23(4): 284-294, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36475346

RESUMO

Engineered nanostructures of mixed transition metal sulfides have emerged as promising nanomaterials (NMs) for various electrochemical sensors and biosensors applications, including glucose sensors (GS) and lactic acid sensors (LAS) in clinical aspects. Electrochemical sensors based on nanostructured materials, such as transition metal sulfides and their nanocomposites, including graphene, carbon nanotubes, molecularly imprinted polymers, and metal-organic frameworks, have emerged as potent tools for the monitoring and quantification of biomolecules. Highly sensitive and selective electrochemical detection systems have generally been established credibly by providing new functional surfaces, miniaturization processes, and different nanostructured materials with exceptional characteristics. This review provides an overview of glucose and lactic acid sensors based on transition metal nanomaterials and their nanocomposites with a detailed discussion about the advantages and challenges. The merits of nanoscale transition metal sulphide-based electrochemical sensors and biosensor systems include cost-effectiveness, ease of miniaturization process, energy- and time-efficient, simple preparation, etc. Moreover, online sensing competence is the dynamic strength for sustained progress of electrochemical detection systems, thus fascinating interdisciplinary research. In particular, we discuss the synthesis, characteristics, electrode construction strategies, and uses in electrochemical sensing of glucose and lactic acid primarily based on our most recent research and other reports. In addition, the challenges and future perspectives of the nanostructured transition metal sulfides-based electrochemical sensing and biosensing systems toward the detection of glucose and lactic acid are described.


Assuntos
Técnicas Biossensoriais , Nanocompostos , Nanoestruturas , Nanotubos de Carbono , Glucose , Ácido Láctico , Nanotubos de Carbono/química , Técnicas Eletroquímicas , Nanoestruturas/química
11.
Biosensors (Basel) ; 12(12)2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36551095

RESUMO

Herein, gold nanoclusters (Au NC) dispersed on gold dendrite (Au DS)-based flexible carbon fibre (AuNC@AuDS|CF) microelectrodes are developed using a one-step electrochemical approach. The as-fabricated AuNC@AuDS|CF microelectrodes work as the prospective electrode materials for the sensitive detection of nitric oxide (NO) in a 0.1 M phosphate buffer (PB) solution. Carbon microfibre acts as an efficient matrix for the direct growth of AuNC@AuDS without any binder/extra reductant. The AuNC@AuDS|CF microelectrodes exhibit outstanding electrocatalytic activity towards NO oxidation, which is ascribed to their large electrochemical active surface area (ECSA), high electrical conductivity, and high dispersion of Au nanoclusters. As a result, the AuNC@AuDS|CF microelectrodes attain a rapid response time (3 s), a low limit of detection (LOD) (0.11 nM), high sensitivity (66.32 µA µM cm-2), a wide linear range (2 nM-7.7 µM), long-term stability, good reproducibility, and a strong anti-interference capability. Moreover, the present microsensor successfully tested for the discriminating detection of NO in real human serum samples, revealing its potential practicability.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Humanos , Microeletrodos , Fibra de Carbono , Óxido Nítrico , Ouro , Reprodutibilidade dos Testes , Estudos Prospectivos , Carbono , Dendritos , Técnicas Eletroquímicas
12.
Nanomaterials (Basel) ; 12(20)2022 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-36296823

RESUMO

The electro-oxidation of urea (EOU) is a remarkable but challenging sustainable technology, which largely needs a reduced electro-chemical potential, that demonstrates the ability to remove a notable harmful material from wastewater and/or transform the excretory product of humans into treasure. In this work, an Ni2P-nanoparticle-integrated porous nickel oxide (NiO) hetero-structured nanosheet (Ni2P@NiO/NiF) catalyst was synthesized through in situ acid etching and a gas-phase phosphating process. The as-synthesized Ni2P@NiO/NiF catalyst sample was then used to enhance the electro-oxidation reaction of urea with a higher urea oxidation response (50 mA cm-2 at 1.31 V vs. RHE) and low onset oxidation potential (1.31 V). The enhanced activity of the Ni2P@NiO/NiF catalyst was mainly attributed to effective electron transport after Ni2P nanoparticle insertion through a substantial improvement in active sites due to a larger electrochemical surface area, and a faster diffusion of ions occurred via the interactive sites at the interface of Ni2P and NiO; thus, the structural reliability was retained, which was further evidenced by the low charge transfer resistance. Further, the Ni2P nanoparticle insertion process into the NiO hetero-structured nanosheets effectively enabled a synergetic effect when compared to the counter of the Ni2P/NiF and NiO/NiF catalysts. Finally, we demonstrate that the as-synthesized Ni2P@NiO/NiF catalyst could be a promising electrode for the EOU in urea-rich wastewater and human urine samples for environmental safety management. Overall, the Ni2P@NiO/NiF catalyst electrode combines the advantages of the Ni2P catalyst, NiO nanosheet network, and NiF current collector for enhanced EOU performance, which is highly valuable in catalyst development for environmental safety applications.

13.
Nanomaterials (Basel) ; 11(11)2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34835623

RESUMO

Structural engineering is an effective methodology for the tailoring of the quantities of active sites in nanostructured materials for fuel cell applications. In the present study, Co nanoparticles were incorporated into the network of 3D nitrogen-doped carbon tubes (Co@NCNTs) that were obtained via the molten-salt synthetic approach at 800 °C. Morphological representation reveals that the Co@NCNTs are encompassed with Co nanoparticles on the surface of the mesoporous walls of the carbon nanotubes, which offers a significant active surface area for electrochemical reactions. The CoNPs/NCNTs-1 (treated with CaCl2) nanomaterial was used as a potential candidate for the electro-oxidation of hydrazine, which improved the response of hydrazine (~8.5 mA) in 1.0 M NaOH, as compared with CoNPs/NCNTs-2 (treated without CaCl2), NCNTs, and the unmodified GCE. Furthermore, the integration of Co helps to improve the conductivity and promote the lower onset electro-oxidation potential (-0.58 V) toward the hydrazine electro-oxidation reaction. In particular, the CoNPs/NCNTs-1 catalysts showed significant catalytic activity and stability performances i.e., the i-t curves showed notable stability when compared with their initial current responses, even after 10 days, which indicates the significant durability of the catalyst materials. This work could present a new approach for the design of efficient electrode materials, which can be used as a favorable candidate for the electro-oxidation of liquid fuels in fuel cell applications.

14.
Analyst ; 146(23): 7168-7177, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34700332

RESUMO

The uneven distribution of metal nanoparticles is a vital influencing factor in the poor uniformity of surface-enhanced Raman scattering (SERS) substrates, which is a challenge in SERS quantitative analysis. Recent reports showed that the reproducibility of a nonuniform SERS substrate can be effectively improved by the use of an internal standard (IS). However, most of these approaches require the investment of time for precise regulation, and those approaches based on the addition of an IS are specific to a certain substrate. In this work, we proposed a simple, rapid and universal method to incorporate an IS into a SERS substrate for improving the reproducibility of Raman signals based on the systematic evaluation of the influencing factors of the competitive adsorption between the IS and the target analytes. Following the proposed pressure drop-coating (PDC) method, an IS-modified gold nanobipyramids (Au NBPs)/anodic aluminum oxide (AAO) SERS substrate was fabricated within 1 min, showing high reproducibility of Raman signals. In addition, the IS-modified Au NBPs/AAO SERS substrate was successfully applied to analyze thiram in freshly squeezed apple juice and the result showed a stable Raman signal with a relative standard deviation of less than 6.00%. What is more, three different commercial SERS chips were modified with an IS molecule using the PDC method. Compared to the traditional SERS chips, the Raman signal reproducibility of the functionalized SERS chips was improved significantly. Since the addition of an IS is not based on a certain substrate, the proposed approach could be useful for all the researchers working in the field of SERS.


Assuntos
Ouro , Nanopartículas Metálicas , Limite de Detecção , Reprodutibilidade dos Testes , Análise Espectral Raman
15.
Micromachines (Basel) ; 13(1)2021 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-35056240

RESUMO

Diabetes is a foremost health issue that results in ~4 million deaths every year and ~170 million people suffering globally. Though there is no treatment for diabetes yet, the blood glucose level of diabetic patients should be checked closely to avoid further problems. Screening glucose in blood has become a vital requirement, and thus the fabrication of advanced and sensitive blood sugar detection methodologies for clinical analysis and individual care. Bimetallic nanoparticles (BMNPs) are nanosized structures that are of rising interest in many clinical applications. Although their fabrication shares characteristics with physicochemical methodologies for the synthesis of corresponding mono-metallic counterparts, they can display several interesting new properties and applications as a significance of the synergetic effect between their two components. These applications can be as diverse as clinical diagnostics, anti-bacterial/anti-cancer treatments or biological imaging analyses, and drug delivery. However, the exploitation of BMNPs in such fields has received a small amount of attention predominantly due to the vital lack of understanding and concerns mainly on the usage of other nanostructured materials, such as stability and bio-degradability over extended-time, ability to form clusters, chemical reactivity, and biocompatibility. In this review article, a close look at bimetallic nanomaterial based glucose biosensing approaches is discussed, concentrating on their clinical applications as detection of glucose in various real sample sources, showing substantial development of their features related to corresponding monometallic counterparts and other existing used nanomaterials for clinical applications.

16.
Analyst ; 145(20): 6524-6531, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-32760976

RESUMO

The detection of biomarkers in exhaled breath condensates (EBCs) is regarded as a promising non-invasive diagnostic approach. However, the ultralow concentration of biomarkers in EBCs is a great challenge. Herein, a sensitive dual signal amplification strategy was developed based on surface-enhanced electrochemiluminescence (SEECL) combined with resonance energy transfer (RET). Gold nanoparticles-functionalized graphite-like carbon nitride nanohybrids (Au-g-C3N4 NHs) could be used as an energy transfer donor because of the good overlap between its emission peak and the absorption peak of tris(2,2'-bipyridine)ruthenium dichloride (Ru(bpy)3Cl2) at 460 nm. Gold-silicon dioxide core-shell nanoparticles doped with Ru(bpy)32+(Au@SiO2-Ru) were employed as an energy transfer acceptor emitting at 620 nm. Moreover, the signals at 620 nm emitted by Ru (bpy)32+ were enhanced by 5 times, attributed to the localized surface plasmon resonance (LSPR) of gold nanoparticles (Au NPs). The detection of carcinoembryonic antigen (CEA) was performed by using two aptamers as the recognition unit; whereby aptamer 1 (Apt1) was modified on the surface of Au-g-C3N4 NHs, and aptamer 2 (Apt2) was banded on the surface of Au@SiO2-Ru. In the presence of CEA, a sandwich structure was formed between Au-g-C3N4 NHs-Apt1-CEA and Apt2-Au@SiO2-Ru, which resulted in an ultrasensitive detection of CEA. The proposed electrochemiluminescence sensor showed a wide linear relationship with the CEA concentration in the range from 1.0 pg mL-1 to 5.0 ng mL-1, with a limit of detection (LOD) of 0.3 pg mL-1. Finally, the practicality of the proposed sensor was demonstrated to detect CEA in EBCs, and the obtained results were in good agreement with the enzyme-linked immunosorbent assay (ELISA) method.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Testes Respiratórios , Antígeno Carcinoembrionário , Técnicas Eletroquímicas , Transferência de Energia , Ouro , Limite de Detecção , Medições Luminescentes , Dióxido de Silício
17.
Anal Chim Acta ; 1110: 56-63, 2020 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-32278400

RESUMO

In this work, core-satellite assemblies and exonuclease assisted double amplification strategy is developed to produce surface-enhanced Raman scattering (SERS) biosensor towards ultrasensitive detection of biotoxin. In the presence of target molecules, the exonuclease III (Exo III) assisted efficient recycling amplification provides an excellent pathway for the fabrication of core-satellite SERS sensor. Briefly, the proposed strategy includes the following double amplifications: (i) Exo III induced target-related signal amplification; (ii) core-satellite assemblies assisted formation of SERS "hot-spots" induced signal amplification. To show the applicability of the suggested strategy, the detection of ochratoxin A (OTA), one of the most toxic and widely distributed biotoxin, is demonstrated as an example. The results show that the limit of detection (LOD) of OTA is 0.83 fg mL-1 (S/N = 3). On the basis of the DNA aptamer induced specific target recognition, hence our sensing strategy is easy to be expended to the ultrasensitive detection of other targets, e.g., DNAs, RNAs, and other molecules that have corresponding DNA aptamers.


Assuntos
Técnicas Biossensoriais , Exodesoxirribonucleases/metabolismo , Ocratoxinas/análise , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Exodesoxirribonucleases/química , Ocratoxinas/metabolismo , Análise Espectral Raman , Propriedades de Superfície
18.
Talanta ; 209: 120511, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31892041

RESUMO

An electrochemical immuno-nanogenosensor is developed based on noble-metal-free nickel phosphate nanostructure (NiPNs) as an excellent biocompatible material for miRNA detection in blood serum and urine samples without using indicators for the first time. The pompon flower-like morphology of NiPNs is synthesized, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction pattern (XRD), fourier transform-infrared spectroscopy (FT-IR), and electrochemical impedance methods. The novel NiPNs nanostructured interface was constructed by coordinate covalent bonding between Ni and phosphate group of probe DNA. The constructed NiPNs-p-DNA surface served as the amplified hybridization platform enabling efficient access to numerous target microRNA sequences. As a result, the developed NiPFNs biosensing platform displayed excellent sensitivity, selectivity, and ultralow experimental limit-of-detection (LOD) of 0.034 pM (S/N = 3) as compared with other Ni phosphide nanostructures. This simple and efficient approach is highly suitable for the development of point-of-care detection systems. To the extent of our knowledge, this is the first report on trace level detection of miRNAs employing non-noble Ni metal nanostructures based biosensing platform.


Assuntos
MicroRNAs/sangue , MicroRNAs/urina , Nanoestruturas/química , Níquel/química , Fosfatos/química , Técnicas Biossensoriais/métodos , DNA/química , DNA/genética , Sondas de DNA/química , Sondas de DNA/genética , Espectroscopia Dielétrica , Limite de Detecção , MicroRNAs/genética , Hibridização de Ácido Nucleico
19.
Food Chem ; 307: 125528, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31648181

RESUMO

Simple, rapid, convenient, and economical surface enhanced Raman scattering (SERS) substrate is developed for on-site evaluation of Aflatoxin B1 (AFB1) in food matrix using handheld Raman Spectrometer. Self-assembly of gold nanobipyramids (Au NBPs) into the nanoholes of anodic aluminum oxide (AAO) template/pattern using 'drop-dry' approach provides a reliable pathway for the rapid fabrication of highly active and uniform SERS substrate. It shows enhanced and reproducible SERS signals towards the probe molecule, 4-aminothiophenol (4-ATP) with a relative standard deviation (RSD) of less than 10% and an average enhancement factor (EF) of 1 × 108. For practical application, the proposed method is demonstrated for the detection of aflatoxin B1 (AFB1) in peanut extracts. The results show that the AFB1 in peanut extracts can be identified within 1 min, with a limit of detection of 0.5 µg/L. Compared with conventional ELISA based AFB1 analysis, our method is much more efficient (1 min versus >30 min).


Assuntos
Aflatoxina B1/análise , Arachis/química , Nanoestruturas/química , Extratos Vegetais/química , Análise Espectral Raman/métodos , Óxido de Alumínio/química , Arachis/metabolismo , Ouro/química , Limite de Detecção
20.
Anal Chem ; 91(23): 14792-14802, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31692335

RESUMO

Electrochemiluminescence immunoassays are usually carried out through "on-electrode" strategy, i.e., sandwich-type immunoassay format, the sensitivity of which is restricted by two key bottlenecks: (1) the number of signal labels is limited and (2) only a part of signal labels could participate in the electrode reaction. In this Perspective, we discuss the development of an "in-electrode" Faraday-cage-type concept-based immunocomplex immobilization strategy. The biggest difference from the traditional sandwich-type one is that the designed "in-electrode" Faraday-cage-type immunoassay uses a conductive two-dimensional (2-D) nanomaterial simultaneously coated with signal labels and a recognition component as the detection unit, which could directly overlap on the electrode surface. In such a case, electrons could flow freely from the electrode to the detection unit, the outer Helmholtz plane (OHP) of the electrode is extended, and thousands of signal labels coated on the 2-D nanomaterial are all electrochemically "effective." Thus, then, the above-mentioned bottlenecks obstructing the improvement of the sensitivity in sandwich-type immunoassay are eliminated, and as a result a much higher sensitivity of the Faraday-cage-type immunoassay can be obtained. And, the applications of the proposed versatile "in-electrode" Faraday-cage-type immunoassay have been explored in the detection of target polypeptide, protein, pathogen, and microRNA, with the detection sensitivity improved tens to hundreds of times. Finally, the outlook and challenges in the field are summarized. The rise of Faraday-cage-type electrochemiluminescence immunoassay (FCT-ECLIA)-based biosensing strategies opens new horizons for a wide range of early clinical identification and diagnostic applications.


Assuntos
Anticorpos/química , Técnicas Biossensoriais , Técnicas Eletroquímicas , Imunoensaio , Nanoestruturas/química , Eletrodos , Óxido Ferroso-Férrico/química , Ouro/química , Grafite/química , Humanos , Limite de Detecção , Luminescência , MicroRNAs/análise , Neurotensina/análise , Vibrio parahaemolyticus/química , Vibrio parahaemolyticus/isolamento & purificação , Vibrio vulnificus/química , Vibrio vulnificus/isolamento & purificação , Fatores de Transcrição de p300-CBP/análise
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