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1.
J Environ Sci (China) ; 103: 185-195, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33743900

RESUMEN

In this work, Bi2XO6 (X = W, Mo) are synthesized at different temperatures. The results of tests find the optimal temperatures of Bi2WO6 and Bi2MoO6 are 180 and 160°C (BW-180, BM-160). Then, BW-180 and BM-160 are further compounded with different contents of CuS. The results of photoelectrochemical (PEC) tests show that CuS can improve the PEC performance of semiconductor materials, and it has better performance when CuS mass fraction is 5%. These maybe the photoelectron potentials generated by CuS/Bi2XO6 (X = Mo, W) heterojunction reduce the combination of photogenerated electrons and holes. When the PEC sensor based on 5%-CuS/BW-180 detects Cr(VI), it has a linear range of 1-80 µmol/L with detection limit of 0.95 µmol/L, while the PEC sensor based on 5%-CuS/BM-160 detects Cr(VI) has a linear range of 0.5-230 µmol/L and a detection limit of 0.12 µmol/L. Thus, 5%-CuS/Bi2XO6 has potential application in hexavalent chromium detection.


Asunto(s)
Cromo , Técnicas Electroquímicas , Cobre
2.
Nat Commun ; 12(1): 1868, 2021 03 25.
Artículo en Inglés | MEDLINE | ID: mdl-33767166

RESUMEN

It is very attractive yet underexplored to synthesize heterocyclic moieties pertaining to biologically active molecules from biomass-based starting compounds. Herein, we report an electrocatalytic Achmatowicz reaction for the synthesis of hydropyranones from furfuryl alcohols, which can be readily produced from biomass-derived and industrially available furfural. Taking advantage of photo-induced polymerization of a bipyridyl ligand, we demonstrate the facile preparation of a heterogenized nickel electrocatalyst, which effectively drives the Achmatowicz reaction electrochemically. A suite of characterization techniques and density functional theory computations were performed to aid the understanding of the reaction mechanism. It is rationalized that the unsaturated coordination sphere of nickel sites in our electrocatalyst plays an important role at low applied potential, not only allowing the intimate interaction between the nickel center and furfuryl alcohol but also enabling the transfer of hydroxide from nickel to the bound furfuryl alcohol.


Asunto(s)
Técnicas Electroquímicas/métodos , Furanos/química , 2,2'-Dipiridil/química , Biomasa , Catálisis , Níquel/química
3.
Biosens Bioelectron ; 180: 113112, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33706158

RESUMEN

Infectious diseases caused by viruses can elevate up to undesired pandemic conditions affecting the global population and normal life function. These in turn impact the established world economy, create jobless situations, physical, mental, emotional stress, and challenge the human survival. Therefore, timely detection, treatment, isolation and prevention of spreading the pandemic infectious diseases not beyond the originated town is critical to avoid global impairment of life (e.g., Corona virus disease - 2019, COVID-19). The objective of this review article is to emphasize the recent advancements in the electrochemical diagnostics of twelve life-threatening viruses namely - COVID-19, Middle east respiratory syndrome (MERS), Severe acute respiratory syndrome (SARS), Influenza, Hepatitis, Human immunodeficiency virus (HIV), Human papilloma virus (HPV), Zika virus, Herpes simplex virus, Chikungunya, Dengue, and Rotavirus. This review describes the design, principle, underlying rationale, receptor, and mechanistic aspects of sensor systems reported for such viruses. Electrochemical sensor systems which comprised either antibody or aptamers or direct/mediated electron transfer in the recognition matrix were explicitly segregated into separate sub-sections for critical comparison. This review emphasizes the current challenges involved in translating laboratory research to real-world device applications, future prospects and commercialization aspects of electrochemical diagnostic devices for virus detection. The background and overall progress provided in this review are expected to be insightful to the researchers in sensor field and facilitate the design and fabrication of electrochemical sensors for life-threatening viruses with broader applicability to any desired pathogens.


Asunto(s)
Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Virosis/diagnóstico , Anticuerpos Antivirales/inmunología , Humanos , Técnicas Analíticas Microfluídicas , Técnica SELEX de Producción de Aptámeros
4.
Sensors (Basel) ; 21(5)2021 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-33668211

RESUMEN

The electrochemical-based detection of uric acid (UA) is widely used for diagnostic purposes. However, various interfering species such as ascorbic acid, dopamine, and glucose can affect electrochemical signals, and hence there is an outstanding need to develop improved sensing platforms to detect UA with high selectivity. Herein, we report a pentagonal mediator-based non-enzymatic electrochemical biosensing platform to selectively measure UA in the presence of interfering species. The working electrode was fabricated by electrodepositing polymerized 1-vinylimidazole (PVI), which has an imidazole ligand, onto indium tin oxide (ITO), and then conjugating nickel ions to the PVI-coated ITO electrode. Electrode performance was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements and integrated together with pentacyanoammineferrate, which can bind to the amine groups of UA and function as an electron transferring mediator. The experimental results showed a wide linear range of UA concentration-dependent responses and the multi-potential step (MPS) technique facilitated selective detection of UA in the presence of physiologically relevant interfering species. Altogether, these findings support that pentacyanoammineferrate-based non-enzymatic electrodes are suitable biosensing platforms for the selective measurement of UA, and such approaches could potentially be extended to other bioanalytes as well.


Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , Ferrocianuros/química , Ácido Úrico/análisis , Electrodos
5.
Mikrochim Acta ; 188(3): 105, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33651173

RESUMEN

Severe acute respiratory syndrome SARS-CoV-2 has caused a global pandemic starting in 2020. Accordingly, testing is crucial for mitigating the economic and public health effects. In order to facilitate point-of-care diagnosis, this study aims at presenting a label-free electrochemical biosensor as a powerful nanobiodevice for SARS-CoV-2 spike protein detection. Utilizing the IgG anti-SARS-CoV-2 spike antibody onto the electrode surface as a specific platform in an ordered orientation through staphylococcal protein A (ProtA) is highly significant in fabricating the designed nanobiodevice. In this sense, the screen-printed carbon electrode modified with Cu2O nanocubes (Cu2O NCs), which provide a large surface area in a very small space, was applied in order to increase the ProtA loading on the electrode surface. Accordingly, the sensitivity and stability of the sensing platform significantly increased. The electrochemical evaluations proved that there is a very good linear relationship between the charge transfer resistance (Rct) and spike protein contents via a specific binding reaction in the range 0.25 fg mL-1 to 1 µg mL-1. Moreover, the assay when tested with influenza viruses 1 and 2 was performed in 20 min with a low detection limit of 0.04 fg mL-1 for spike protein without any cross-reactivity. The designed nanobiodevice exhibited an average satisfactory recovery rate of ~ 97-103% in different artificial sample matrices, i.e., saliva, artificial nasal, and universal transport medium (UTM), illustrating its high detection performance and practicability. The nanobiodevice was also tested using real patients and healthy samples, where the results had been already obtained using the standard polymerase chain reaction (PCR) procedure, and showed satisfactory results. Graphical abstract.


Asunto(s)
Técnicas Biosensibles/métodos , /diagnóstico , Cobre/química , Técnicas Electroquímicas/métodos , Nanoestructuras/química , Glicoproteína de la Espiga del Coronavirus/análisis , Anticuerpos Antivirales/metabolismo , Electrodos , Humanos , Inmunoensayo/métodos , Inmunoglobulina G/metabolismo , Unión Proteica , Sensibilidad y Especificidad , Proteína Estafilocócica A/química , Propiedades de Superficie
6.
Molecules ; 26(4)2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33672044

RESUMEN

In spite of unique structural, spectroscopic and redox properties, the synthetic variants of the planar, antiaromatic hexaphyrin (1.0.1.0.1.0) derivatives 2, has been limited due to the low yields and difficulty in access to the starting material. A chemical modification of the meso-substituents could be good alternative overcoming the synthetic barrier. Herein, we report a regio-selective nucleophilic aromatic substitution (SNAr) of meso-pentafluorophenyl group in rosarrin 2 with catechol. The reaction afforded benzodioxane fused rosarrin 3 as single product with high yield. The intrinsic antiaromatic character of the starting rosarrin 2 retained throughout the reactions. Clean, two electron reduction was achieved by treatment of 3 with SnCl2•2H2O affording 26π-electron aromatic rosarrin 4. The synthesized compounds exhibited noticeable changes in photophysical and redox properties compared with starting rosarrin 2.


Asunto(s)
Porfirinas/química , Porfirinas/síntesis química , Técnicas Electroquímicas , Espectrofotometría Ultravioleta , Estereoisomerismo
7.
Molecules ; 26(5)2021 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-33668393

RESUMEN

We herein report the design and synthesis of small-donor molecules, 2,1,3-benzothiadiazole derivatives (2a-d), by Stille or Suzuki reaction. The synthesized compounds were characterized by spectroscopic and electrochemical methods. The compounds 2a-d absorb the light in a wide range (the UV-green/yellow light (2c)) and emit from green to red/near IR light (2c). Furthermore, these compounds show a narrow energy gap (1.75-2.38 eV), and high Ea values increasing for polymers, which prove their electron-donating nature and semiconductor properties. The measurements were enhanced by theoretical modeling.


Asunto(s)
Teoría Funcional de la Densidad , Técnicas Electroquímicas , Tiadiazoles/química , Estructura Molecular , Fenómenos Ópticos , Tiadiazoles/síntesis química
8.
Adv Mater ; 33(10): e2007847, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33538037

RESUMEN

The graphene revolution, which has taken place during the last 15 years, has represented a paradigm shift for science. The extraordinary properties possessed by this unique material have paved the road to a number of applications in materials science, optoelectronics, energy, and sensing. Graphene-related materials (GRMs) are now produced in large scale and have found niche applications also in the biomedical technologies, defining new standards for drug delivery and biosensing. Such advances position GRMs as novel tools to fight against the current COVID-19 and future pandemics. In this regard, GRMs can play a major role in sensing, as an active component in antiviral surfaces or in virucidal formulations. Herein, the most promising strategies reported in the literature on the use of GRM-based materials against the COVID-19 pandemic and other types of viruses are showcased, with a strong focus on the impact of functionalization, deposition techniques, and integration into devices and surface coatings.


Asunto(s)
/diagnóstico , Grafito/química , Nanoestructuras/química , Anticuerpos Inmovilizados/química , Anticuerpos Inmovilizados/inmunología , Antivirales/química , Antivirales/farmacología , Técnicas Biosensibles/métodos , /virología , Técnicas Electroquímicas , Electrodos , Humanos , Límite de Detección , Nanoestructuras/toxicidad , /aislamiento & purificación , Propiedades de Superficie , Proteínas Virales/análisis , Proteínas Virales/inmunología
9.
Food Chem ; 351: 129252, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33626469

RESUMEN

Herein, an innovative enzyme free electrochemiluminescence chlorpyrifos sensor was reported based on the incorporation of ternary nanocomposite (ruthenium nanobeads/silver nanoparticles/graphene oxide) on the surface of glassy carbon electrode. The silver nanoparticles as a robust signal enhancing agent were well deposited on the modified graphene oxide/glassy carbon electrode and exhibited supreme electrocatalytic proficiency. Then, Ru(bipy)32+ species in bead-like nanoparticles were uniformly anchored on the surface of the modified electrode with the help of chitosan, as a good crosslinking agent. Boron nitride quantum dots as a new coreactant species showed the excellent proficiency for signal enhancement of the fabricated electrode. The fabricated electrode was successfully used as an ultra-sensitive sensor for trace analysis of chlorpyrifos by ECL technique. The wide linear range and the low detection limit were obtained from 5.0 × 10-15 to 4.2 × 10-9 M and 6.5 × 10-16 M, respectively.


Asunto(s)
Cloropirifos/análisis , Técnicas Electroquímicas/métodos , Mediciones Luminiscentes/métodos , Nanocompuestos/química , Compuestos de Boro/química , Catálisis , Técnicas Electroquímicas/instrumentación , Electrodos , Grafito/química , Límite de Detección , Mediciones Luminiscentes/instrumentación , Nanopartículas del Metal/química , Puntos Cuánticos/química , Rutenio/química , Plata/química
10.
Sensors (Basel) ; 21(4)2021 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-33572293

RESUMEN

Chloramphenicol (CAP) is a harmful compound associated with human hematopathy and neuritis, which was widely used as a broad-spectrum antibacterial agent in agriculture and aquaculture. Therefore, it is significant to detect CAP in aquatic environments. In this work, carbon nanotubes/silver nanowires (CNTs/AgNWs) composite electrodes were fabricated as the CAP sensor. Distinguished from in situ growing or chemical bonding noble metal nanomaterials on carbon, this CNTs/AgNWs composite was formed by simple solution blending. It was demonstrated that CNTs and AgNWs both contributed to the redox reaction of CAP in dynamics, and AgNWs was beneficial in thermodynamics as well. The proposed electrochemical sensor displayed a low detection limit of up to 0.08 µM and broad linear range of 0.1-100 µM for CAP. In addition, the CNTs/AgNWs electrodes exhibited good performance characteristics of repeatability and reproducibility, and proved suitable for CAP analysis in real water samples.


Asunto(s)
Cloranfenicol , Nanotubos de Carbono , Nanocables , Cloranfenicol/análisis , Técnicas Electroquímicas , Electrodos , Humanos , Reproducibilidad de los Resultados , Plata
11.
Biosensors (Basel) ; 11(2)2021 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-33525714

RESUMEN

A graphene sample (EGr) was prepared by electrochemical exfoliation of graphite rods in solution containing 0.05 M (NH4)2SO4 + 0.1 M H3BO3 + 0.05 M NaCl. The exfoliation was performed by applying a constant voltage (12 V) between the graphite rods, while the temperature was kept constant (18 °C) with a temperature-controlled cryostat. The structural investigation of the graphene sample, performed by X-ray powder diffraction (XRD), revealed that the sample consists of a mixture of few-layer (69%), multi-layer graphene (14%) and graphene oxide (17%). In addition, XPS analysis proved that the sample was triple-doped with heteroatoms such as nitrogen (1.7 at%), sulfur (2.5 at%), and boron (3 at%). The sample was deposited onto the surface of a clean, glassy carbon electrode (GC) and investigated for the non-enzymatic electrochemical detection of L-tryptophan (TRP). The electrocatalytic properties of the EGr/GC electrode led to a considerable decrease in the oxidation potential from +0.9 V (bare GC) to +0.72 V. In addition, the EGr/GC electrode has higher sensitivity (two times) and a lower detection limit (ten times) in comparison with the bare GC electrode.


Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , Electrodos , Grafito/química , Triptófano/análisis , Oxidación-Reducción
12.
Biosensors (Basel) ; 11(2)2021 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-33562505

RESUMEN

Circulating tumour DNA (ctDNA) is widely used in liquid biopsies due to having a presence in the blood that is typically in proportion to the stage of the cancer and because it may present a quick and practical method of capturing tumour heterogeneity. This paper outlines a simple electrochemical technique adapted towards point-of-care cancer detection and treatment monitoring from biofluids using a label-free detection strategy. The mutations used for analysis were the KRAS G12D and G13D mutations, which are both important in the initiation, progression and drug resistance of many human cancers, leading to a high mortality rate. A low-cost DNA sensor was developed to specifically investigate these common circulating tumour markers. Initially, we report on some developments made in carbon surface pre-treatment and the electrochemical detection scheme which ensure the most sensitive measurement technique is employed. Following pre-treatment of the sensor to ensure homogeneity, DNA probes developed specifically for detection of the KRAS G12D and G13D mutations were immobilized onto low-cost screen printed carbon electrodes using diazonium chemistry and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide coupling. Prior to electrochemical detection, the sensor was functionalised with target DNA amplified by standard and specialist PCR methodologies (6.3% increase). Assay development steps and DNA detection experiments were performed using standard voltammetry techniques. Sensitivity (as low as 0.58 ng/µL) and specificity (>300%) was achieved by detecting mutant KRAS G13D PCR amplicons against a background of wild-type KRAS DNA from the representative cancer sample and our findings give rise to the basis of a simple and very low-cost system for measuring ctDNA biomarkers in patient samples. The current time to receive results from the system was 3.5 h with appreciable scope for optimisation, thus far comparing favourably to the UK National Health Service biopsy service where patients can wait for weeks for biopsy results.


Asunto(s)
Técnicas Biosensibles , Mutación Puntual , ADN , Técnicas Electroquímicas , Subunidades alfa de la Proteína de Unión al GTP G12-G13 , Mutación , Proteínas Proto-Oncogénicas p21(ras)
13.
Biosensors (Basel) ; 11(2)2021 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-33579006

RESUMEN

An origami three-dimensional design of a paper-based potentiometric sensor is described. In its simplest form, this electrochemical paper-based analytical device (ePAD) is made from three small parts of the paper. Paper layers are folded on each other for the integration of a solid contact ion selective electrode (here a carbon-paste composite electrode) and a solid-state pseudo-reference electrode (here writing pencil 6B on the paper), which are in contact with a hydrophilic channel fabricated on the middle part (third part) of the paper. In this case, the pseudo-reference and working electrodes are connected to the two sides of the hydrophilic channel and hence the distance between them is as low as the width of paper. The unmodified carbon paste electrode (UCPE) and modification with the crown ether benzo15-crown-5 (B15C5) represented a very high sensitivity to Cu (II) and Cd2+ ions, respectively. The sensor responded to H2O2 using MnO2-doped carbon paste electrode (CPE). Furthermore, a biosensor was achieved by the addition of glucose oxidase to the MnO2-doped CPE and hence made it selective to glucose with ultra-sensitivity. In addition to very high sensitivity, our device benefits from consuming a very low volume of sample (10.0 µL) and automatic sampling without need for sampling devices.


Asunto(s)
Técnicas Biosensibles/instrumentación , Técnicas Analíticas Microfluídicas , Potenciometría/métodos , Carbono , Técnicas Electroquímicas , Electrodos , Glucosa Oxidasa , Peróxido de Hidrógeno , Electrodos de Ion-Selectivo , Compuestos de Manganeso , Microfluídica , Óxidos
14.
Sensors (Basel) ; 21(4)2021 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-33562790

RESUMEN

Deoxyribonucleic acid (DNA) electrochemical biosensors are devices that incorporate immobilized DNA as a molecular recognition element on the electrode surface, and enable probing in situ the oxidative DNA damage. A wide range of DNA electrochemical biosensor analytical and biotechnological applications in pharmacology are foreseen, due to their ability to determine in situ and in real-time the DNA interaction mechanisms with pharmaceutical drugs, as well as with their degradation products, redox reaction products, and metabolites, and due to their capacity to achieve quantitative electroanalytical evaluation of the drugs, with high sensitivity, short time of analysis, and low cost. This review presents the design and applications of label-free DNA electrochemical biosensors that use DNA direct electrochemical oxidation to detect oxidative DNA damage. The DNA electrochemical biosensor development, from the viewpoint of electrochemical and atomic force microscopy (AFM) characterization, and the bottom-up immobilization of DNA nanostructures at the electrode surface, are described. Applications of DNA electrochemical biosensors that enable the label-free detection of DNA interactions with pharmaceutical compounds, such as acridine derivatives, alkaloids, alkylating agents, alkylphosphocholines, antibiotics, antimetabolites, kinase inhibitors, immunomodulatory agents, metal complexes, nucleoside analogs, and phenolic compounds, which can be used in drug analysis and drug discovery, and may lead to future screening systems, are reviewed.


Asunto(s)
Técnicas Biosensibles , Daño del ADN , Estrés Oxidativo/fisiología , Preparaciones Farmacéuticas , ADN , Técnicas Electroquímicas , Oxidación-Reducción
15.
Anal Methods ; 13(7): 874-883, 2021 02 25.
Artículo en Inglés | MEDLINE | ID: mdl-33576354

RESUMEN

Using the children's toy, Shrinky-Dink©, we present an aptamer-based electrochemical (E-AB) assay that recognizes the spike protein of SARS-CoV-2 in saliva for viral infection detection. The low-cost electrodes are implementable at population scale and demonstrate detection down to 1 ag mL-1 of the S1 subunit of the spike protein.


Asunto(s)
Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Poliestirenos/química , Saliva/química , Glicoproteína de la Espiga del Coronavirus/análisis , Aptámeros de Nucleótidos/química , Técnicas Electroquímicas/instrumentación , Electrodos , Oro/química , Humanos , Límite de Detección , Dominios Proteicos , Glicoproteína de la Espiga del Coronavirus/química
16.
ACS Appl Mater Interfaces ; 13(7): 7897-7912, 2021 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-33570904

RESUMEN

Titanium dioxide (TiO2) nanostructures including nanopores and nanotubes have been fabricated on titanium (Ti)-based orthopedic/dental implants via electrochemical anodization (EA) to enable local drug release and enhanced bioactivity. EA using organic electrolytes such as ethylene glycol often requires aging (repeated anodization of nontarget Ti) to fabricate stable well-ordered nanotopographies. However, limited information is available with respect to its influence on topography, chemistry, mechanical stability, and bioactivity of the fabricated structures. In the current study, titania nanopores (TNPs) using a similar voltage/time were fabricated using different ages of electrolyte (fresh/0 h to 30 h aged). Current density vs time plots of EA, changes in the electrolyte (pH, conductivity, and Ti/F ion concentration), and topographical, chemical, and mechanical characteristics of the fabricated TNPs were compared. EA using 10-20 h electrolytes resulted in stable TNPs with uniform size and improved alignment (parallel to the underlying substrate microroughness). Additionally, to evaluate bioactivity, primary human gingival fibroblasts (hGFs) were cultured onto various TNPs in vitro. The findings confirmed that the proliferation and morphology of hGFs were enhanced on 10-20 h aged electrolyte anodized TNPs. This pioneering study systematically investigates the optimization of anodization electrolyte toward fabricating nanoporous implants with desirable characteristics.


Asunto(s)
Nanoporos , Titanio/química , Técnicas Electroquímicas , Electrólitos/química , Flúor/química , Concentración de Iones de Hidrógeno , Tamaño de la Partícula , Propiedades de Superficie , Factores de Tiempo
17.
Nat Commun ; 12(1): 802, 2021 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-33547323

RESUMEN

Coronavirus disease 2019 (COVID-19) is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diagnosis of COVID-19 depends on quantitative reverse transcription PCR (qRT-PCR), which is time-consuming and requires expensive instrumentation. Here, we report an ultrasensitive electrochemical biosensor based on isothermal rolling circle amplification (RCA) for rapid detection of SARS-CoV-2. The assay involves the hybridization of the RCA amplicons with probes that were functionalized with redox active labels that are detectable by an electrochemical biosensor. The one-step sandwich hybridization assay could detect as low as 1 copy/µL of N and S genes, in less than 2 h. Sensor evaluation with 106 clinical samples, including 41 SARS-CoV-2 positive and 9 samples positive for other respiratory viruses, gave a 100% concordance result with qRT-PCR, with complete correlation between the biosensor current signals and quantitation cycle (Cq) values. In summary, this biosensor could be used as an on-site, real-time diagnostic test for COVID-19.


Asunto(s)
Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , /aislamiento & purificación , /virología , Humanos , Técnicas de Amplificación de Ácido Nucleico/métodos , ARN Viral/genética , /fisiología , Sensibilidad y Especificidad
18.
ACS Sens ; 6(3): 1270-1278, 2021 03 26.
Artículo en Inglés | MEDLINE | ID: mdl-33629833

RESUMEN

The COVID-19 pandemic has highlighted the importance and urgent need for rapid and accurate diagnostic tests for COVID-19 detection and screening. The objective of this work was to develop a simple immunosensor for rapid and high sensitivity measurements of SARS-CoV-2 nucleocapsid protein in serum. This assay is based on a unique sensing scheme utilizing dually-labeled magnetic nanobeads for immunomagnetic enrichment and signal amplification. This immunosensor is integrated onto a microfluidic chip, which offers the advantages of minimal sample and reagent consumption, simplified sample handling, and enhanced detection sensitivity. The functionality of this immunosensor was validated by using it to detect SARS-CoV-2 nucleocapsid protein, which could be detected at concentrations as low as 50 pg/mL in whole serum and 10 pg/mL in 5× diluted serum. We also adapted this assay onto a handheld smartphone-based diagnostic device that could detect SARS-CoV-2 nucleocapsid protein at concentrations as low as 230 pg/mL in whole serum and 100 pg/mL in 5× diluted serum. Lastly, we assessed the capability of this immunosensor to diagnose COVID-19 infection by testing clinical serum specimens, which revealed its ability to accurately distinguish PCR-positive COVID-19 patients from healthy, uninfected individuals based on SARS-CoV-2 nucleocapsid protein serum levels. To the best of our knowledge, this work is the first demonstration of rapid (<1 h) SARS-CoV-2 antigen quantification in whole serum samples. The ability to rapidly detect SARS-CoV-2 protein biomarkers with high sensitivity in very small (<50 µL) serum samples makes this platform a promising tool for point-of-care COVID-19 testing.


Asunto(s)
/métodos , /sangre , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , /inmunología , Técnicas Electroquímicas , Humanos , Inmunoensayo , Fenómenos Magnéticos , Microfluídica
19.
J Mater Chem B ; 9(5): 1175-1188, 2021 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-33458727

RESUMEN

The use of sensitive electrochemical sensors to detect biomarkers is an effective method for the early diagnosis of several neurodegenerative diseases (NDs), such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, etc. However, the commercialization of enzyme/aptamer-based sensors is still hampered owing to the historic drawbacks of biorecognition elements including high cost, poor stability, and complex integration technology. Non-enzymatic electrochemical sensors are more attractive compared to their traditional counterparts and can be widely harnessed owing to their low cost, high stability, sensitivity, and ease of miniaturization. This review summarizes recent research progress focusing on the construction of non-enzymatic electrochemical sensors and analyzes their present use in the early diagnosis of NDs. Additionally, this review addresses the limitations and challenges of the use of current non-enzymatic electrochemical sensor technologies for the diagnosis of NDs and highlights the possible directions for future research.


Asunto(s)
Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Enfermedades Neurodegenerativas/diagnóstico , Humanos
20.
Food Chem ; 347: 128980, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33465693

RESUMEN

In order to achieve accurate detection and evaluation of the freshness of fish samples, high sensitivity and selectivity of histamine sensors based on solution-gated graphene transistors (SGGT) have been successfully developed. By using graphene (Gra), multi-walled carbon nanotubes (MWNT) and gold nanoparticles (AuNP) to functionalize the gate electrode, the electrocatalytic performance of the device can be significantly improved. We have found that graphene, MWNT and AuNP modified SGGT sensors exhibit an ultra-low detection limit of 100 nM for histamine, a linear range of 3 µM-100 µM. We have also demonstrated that the SGGT-based histamine sensor has a high recovery rate and is capable of assessing the histamine content of actual fish samples in a fast and accurate manner. Considering the superior performance of the SGGT-based histamine sensor, it can be readily extended to histamine determination in many other real food samples for their freshness assessment.


Asunto(s)
Técnicas Electroquímicas/métodos , Histamina/análisis , Nanopartículas del Metal/química , Nanotubos de Carbono/química , Animales , Técnicas Electroquímicas/instrumentación , Electrodos , Peces/metabolismo , Oro/química , Grafito/química , Límite de Detección , Reproducibilidad de los Resultados , Transistores Electrónicos
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