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1.
Biosensors (Basel) ; 11(6)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34073756

RESUMO

Despite collaborative efforts from all countries, coronavirus disease 2019 (COVID-19) pandemic has been continuing to spread globally, forcing the world into social distancing period, making a special challenge for public healthcare system. Before vaccine widely available, the best approach to manage severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is to achieve highest diagnostic accuracy by improving biosensor efficacy. For SARS-CoV-2 diagnostics, intensive attempts have been made by many scientists to ameliorate the drawback of current biosensors of SARS-CoV-2 in clinical diagnosis to offer benefits related to platform proposal, systematic analytical methods, system combination, and miniaturization. This review assesses ongoing research efforts aimed at developing integrated diagnostic tools to detect RNA viruses and their biomarkers for clinical diagnostics of SARS-CoV-2 infection and further highlights promising technology for SARS-CoV-2 specific diagnosis. The comparisons of SARS-CoV-2 biomarkers as well as their applicable biosensors in the field of clinical diagnosis were summarized to give scientists an advantage to develop superior diagnostic platforms. Furthermore, this review describes the prospects for this rapidly growing field of diagnostic research, raising further interest in analytical technology and strategic plan for future pandemics.


Assuntos
Técnicas Biossensoriais/instrumentação , Teste para COVID-19/instrumentação , SARS-CoV-2/isolamento & purificação , Animais , Técnicas Biossensoriais/métodos , Teste para COVID-19/métodos , Colorimetria/instrumentação , Colorimetria/métodos , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Ensaio de Imunoadsorção Enzimática/instrumentação , Ensaio de Imunoadsorção Enzimática/métodos , Desenho de Equipamento , Humanos , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Técnicas de Amplificação de Ácido Nucleico/métodos , Testes Imediatos
2.
Nat Protoc ; 16(6): 3141-3162, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33931780

RESUMO

The global pandemic of coronavirus disease 2019 (COVID-19) highlights the shortcomings of the current testing paradigm for viral disease diagnostics. Here, we report a stepwise protocol for an RNA-extraction-free nano-amplified colorimetric test for rapid and naked-eye molecular diagnosis of COVID-19. The test employs a unique dual-prong approach that integrates nucleic acid (NA) amplification and plasmonic sensing for point-of-care detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with a sample-to-assay response time of <1 h. The RNA-extraction-free nano-amplified colorimetric test utilizes plasmonic gold nanoparticles capped with antisense oligonucleotides (ASOs) as a colorimetric reporter to detect the amplified nucleic acid from the COVID-19 causative virus, SARS-CoV-2. The ASOs are specific for the SARS-CoV-2 N-gene, and binding of the ASOs to their target sequence results in the aggregation of the plasmonic gold nanoparticles. This highly specific agglomeration step leads to a change in the plasmonic response of the nanoparticles. Furthermore, when tested using clinical samples, the accuracy, sensitivity and specificity of the test were found to be >98.4%, >96.6% and 100%, respectively, with a detection limit of 10 copies/µL. The test can easily be adapted to diagnose other viral infections with a simple modification of the ASOs and primer sequences. It also provides a low-cost, rapid approach requiring minimal instrumentation that can be used as a screening tool for the diagnosis of COVID-19 at point-of-care settings in resource-poor situations. The colorimetric readout of the test can even be monitored using a handheld optical reader to obtain a quantitative response. Therefore, we anticipate that this protocol will be widely useful for the development of biosensors for the molecular diagnostics of COVID-19 and other infectious diseases.


Assuntos
Teste de Ácido Nucleico para COVID-19/métodos , COVID-19/diagnóstico , Ouro/química , Nanopartículas Metálicas/química , Oligonucleotídeos Antissenso/química , RNA Viral/análise , SARS-CoV-2/isolamento & purificação , COVID-19/virologia , Teste de Ácido Nucleico para COVID-19/instrumentação , Colorimetria/instrumentação , Colorimetria/métodos , Humanos , Limite de Detecção , Oligonucleotídeos Antissenso/genética , Testes Imediatos , RNA Viral/genética , SARS-CoV-2/genética
3.
Food Chem ; 358: 129900, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933980

RESUMO

In this work, a syringe needle-based integrated method was designed for the detection of biogenic amines (BAs) in raw meat samples. Based on a sequential process, the needle-based sampling, micro liquid-phase extraction and peroxidase-like catalysis were adopted for the sample collection, target analytes extraction and colorimetric analysis, respectively. The proposed method exhibited high selectivity towards BAs (the total amount of histamine, putrescine and cadaverine was utilized to present the level of BAs), where the linear range is 5-50 µM and 50-1000 µM, and the limit of detection is 1.52 µM. Specifically, the whole process could be completed in a single syringe needle. In addition, due to the minimized sampling, the change of BAs levels with time in different area of real samples (fish) can be conveniently investigated. This method has the advantages of simplicity, low cost, high sensitivity and selectivity, endowing it a promising candidate for food analysis.


Assuntos
Aminas Biogênicas/análise , Colorimetria/métodos , Análise de Alimentos/instrumentação , Carne/análise , Amina Oxidase (contendo Cobre)/química , Animais , Cadaverina/análise , Catálise , Colorimetria/instrumentação , Produtos Pesqueiros/análise , Análise de Alimentos/métodos , Armazenamento de Alimentos , Histamina/análise , Microextração em Fase Líquida , Nanopartículas Metálicas/química , Agulhas , Peroxidase/química , Carne de Porco/análise , Putrescina/análise , Compostos de Estanho/química
4.
Food Chem ; 356: 129692, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-33819791

RESUMO

To increase milk production, antibiotics are administered to animals to provide weight gain and to prevent or treat diseases. The inappropriate use of these substances can lead to antibiotic resistance and allergic reactions and toxic effects to milk consumers. We describe the development of a simple, fast, portable, and low-cost microfluidic paper-based analytical device (µPAD) to quantify sulfonamides in milk using the inhibition of the colorimetric reaction between carbonic anhydrase (CA) and 4-nitrophenyl acetate. The main advantages presented by the µPAD include reproducible batch production, simple application, and precise analysis without previous treatment. The µPAD displayed good linearity (R2 ≥ 0.986) in a wide range of sulfonamides in milk (2.5 to 40.0 µmol L-1), being selective for the drugs even in a highly complex matrix. We expect that this device allows in situ monitoring of milk quality, reducing the prejudicial conditions associated with high concentrations of sulfonamides in milk.


Assuntos
Anidrases Carbônicas/química , Colorimetria/métodos , Leite/química , Papel , Sulfonamidas/química , Animais , Anidrases Carbônicas/metabolismo , Bovinos , Colorimetria/instrumentação , Concentração de Íons de Hidrogênio , Técnicas Analíticas Microfluídicas , Leite/metabolismo , Nitrofenóis/química , Nitrofenóis/metabolismo , Sulfonamidas/metabolismo
5.
Food Chem ; 354: 129578, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-33756331

RESUMO

A microfluidic colorimetric biosensor was developed using thiolated polystyrene microspheres (SH-PSs) for aggregating of gold nanoparticles (AuNPs), a novel hose-based microvalve for controlling the flow direction, and a smartphone imaging APP for monitoring colorimetric signals. Aptamer-PS-cysteamine conjugates were used as detection probes and reacted with Salmonella in samples. Complementary DNA - magnetic nanoparticle (cDNA - MNP) conjugates were used as capture probes, reacted with the free aptamer-PS-cysteamine conjugates. AuNPs were aggregated on the surface of Salmonella-aptamer-PS-cysteamine conjugates, resulting in a visible color change in the detection chamber, which indicating different concentrations of Salmonella. The limit of detection was low to 6.0 × 101 cfu/mL. The microfluidic biosensor exhibited a good specificity. It was evaluated by analyzing salad samples spiked with Salmonella. The recoveries ranged from 91.68% to 113.76%, which indicated its potential application in real samples.


Assuntos
Técnicas Biossensoriais/instrumentação , Colorimetria/instrumentação , Dispositivos Lab-On-A-Chip , Poliestirenos/química , Salmonella/isolamento & purificação , Smartphone , Verduras/microbiologia , Ouro/química , Limite de Detecção , Nanopartículas Metálicas , Microesferas
6.
Food Chem ; 354: 129548, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-33761333

RESUMO

A low-cost and portable paper-based analytical device has been developed for high throughput and on-site monitoring TC residue in milk through visualized colorimetric reaction. The filtration and concentration effect induced by the porous nature of paper contribute to strengthen the color intensity, leading to quantitative and sensitive detection of tetracycline reaching 1 ppm detection limit, with the linear range of 1-100 ppm both in water and milk samples. The applicability was demonstrated by detection of TC in 18 different types of real milk samples with good recovery ranging from 88% to 113%. Furthermore, the dynamic degradation behavior of tetracycline was monitored through the device. To the best of our knowledge, this is the first report of colorimetric detection of tetracycline in milk using the paper-based device. This simple, fast, cost-effective (~$0.50 per device) and equipment-free paper-based platform provides a promising tool for future application in food and environmental safety.


Assuntos
Antibacterianos/análise , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Leite/química , Papel , Tetraciclina/análise , Animais , Colorimetria/instrumentação , Limite de Detecção , Água/química
7.
Talanta ; 225: 121978, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33592726

RESUMO

In modern times, viruses still threaten people's lives. Among them, norovirus was the main pathogenic factor in the cause of gastroenteritis and foodborne illness, of which the GII.4 and GII.17 genotypes are prevalent in China and most parts of the world. A simple and low-cost platform for rapid and accurate norovirus detection remains a major challenge. After the cell-free system and paper-based chromogenic system were optimized, a rapid and specific norovirus detection method was established based on norovirus-specific sequences in combination with toehold switch elements. The development of a visible color change during detection eliminates the need for any complicated instruments. We validated this strategy and its specificity in differentiating GII.4, GII.17, Zika virus, and human coronavirus HKU1. The results showed that the optimized detection system not only provided a simple and rapid detection method for the sufficient differentiation of the two norovirus genotypes but also showed high specificity and no cross-reactivity with other viruses. Using nucleic acid isothermal amplification, this assay showed a limit of detection of 0.5 pM for the GII.4 genotype and 2.6 fM for the GII.17 genotype in reactions that could be observed directly with the naked eye. Our results suggested that this paper-based colorimetric method could serve as a simple and low-cost visual detection method for pathogens in clinical samples, especially in remote or rural areas.


Assuntos
Infecções por Caliciviridae/diagnóstico , Colorimetria/métodos , Gastroenterite/diagnóstico , Infecções por Caliciviridae/virologia , Colorimetria/economia , Colorimetria/instrumentação , Análise Custo-Benefício , Gastroenterite/virologia , Genótipo , Humanos , Norovirus/genética , Norovirus/fisiologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Papel , RNA Viral/genética , Sensibilidade e Especificidade
8.
J Environ Sci Health B ; 56(4): 370-377, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33616003

RESUMO

This study aimed to develop an aptasensor for paraquat detection by gold nanoparticles. The specific aptamer for paraquat was selected by using the SELEX process via capillary electrophoresis. Sixty-three aptamer candidates were amplified by asymmetric PCR and screened for paraquat binding using gold nanoparticles (AuNPs). Aggregation of AuNPs was specifically induced by desorption of paraquat binding aptamers from the surface of AuNPs as a result of aptamer-target interaction leading to the color change from red to purple. Aptamer 77F with the following sequence: 5'-AGGCTTACACCTGAAAAGCGGCTTAATTTACACTACTGTAT-3' was selected as a highly specific aptamer for paraquat. The detection limit of paraquat was 0.267 µg/mL by colorimetry and 1.573 µg/mL by the quartz crystal microbalance (QCM) technique. This aptamer showed specificity for paraquat by colorimetry. Dimethyl phophite, diethyl phophite and O,O diethyl thiophosphate potassium salt did not react by colorimetry but, exhibited a weak nonspecific reaction by QCM. This is first time that an aptasensor was used for detection of paraquat based on QCM. However, the aptasensor based on the colorimetric method simply uses a generation of a signal that can be detected by the naked eye. This technique is rapid, low cost easy to use and suitable for on-site detection of herbicide residue.


Assuntos
Aptâmeros de Nucleotídeos/química , Colorimetria/métodos , Paraquat/análise , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/metabolismo , Técnicas Biossensoriais/métodos , Colorimetria/instrumentação , Eletroforese Capilar , Ouro/química , Herbicidas/análise , Limite de Detecção , Nanopartículas Metálicas/química , Paraquat/metabolismo , Reação em Cadeia da Polimerase , Técnicas de Microbalança de Cristal de Quartzo/métodos , Sensibilidade e Especificidade
9.
ACS Appl Mater Interfaces ; 13(3): 3576-3590, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33449630

RESUMO

The plasmonic properties of gold nanoparticles (AuNPs) are a promising tool to develop sensing alternatives to traditional, enzyme-catalyzed reactions. The need for sensing alternatives, especially in underdeveloped areas of the world, has given rise to the application of nonenzymatic sensing approaches paired with cellulosic substrates to biochemical analysis. Herein, we present three individual, low-step, wet-chemistry, colorimetric assays for three target biomarkers, namely, glucose, uric acid, and free cholesterol, relevant in diabetes control and their translation into paper-based assays and microfluidic platforms for multiplexed analysis. For glucose determination, an in situ AuNPs synthesis approach was applied into the developed µPAD, giving semiquantitative measures in the physiologically relevant range. For uric acid and cholesterol determination, modified AuNPs were used to functionalize paper with a gold-on-paper approach with the optical properties changing based on different aggregation degrees and hydrophobic properties of particles dependent on analyte concentration. These paper-based assays show sensitivity ranges and limits of detection compatible for target analyte level determination and detection limits comparable to those of similar enzymatic, colorimetric systems, relying only on plasmonic transduction without the need for enzymatic activity or other chromogenic substrates. The resulting paper-based assays were integrated into a single 3D, multiplex paper-based device using paper microfluidics, showing the capability for performing different colorimetric assays with distinct requirements in terms of sample flow and sample uptake in test zones using a combination of both horizontal and vertical flows inside the same device. The presented device allows for multiparametric, colorimetric measures of different metabolite levels from a single complex sample matrix drop using digital color analysis, showing the potential for development of low-cost, low-complexity tools for diagnostics toward the point-of-care.


Assuntos
Colorimetria/instrumentação , Ouro/química , Dispositivos Lab-On-A-Chip , Nanopartículas Metálicas/química , Papel , Animais , Biomarcadores/sangue , Glicemia/análise , Colesterol/sangue , Desenho de Equipamento , Cabras , Humanos , Sistemas Automatizados de Assistência Junto ao Leito , Ácido Úrico/análise
10.
Anal Chem ; 93(2): 769-776, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33320532

RESUMO

Highly toxic chlorine gas imposes serious health risks in the workplace. The ability to on-site, real-time monitoring of instantaneous and time-weighted average (TWA) chlorine gas concentrations in a simple, sensitive, accurate, and reliable manner would be highly beneficial to improve workplace health and safety. Here, we propose and experimentally validate a gaseous chlorine detection principle based on a N,N-diethyl-p-phenylenediamine sulfate salt/Cl2 colorimetric reaction-controlled membrane process to regulate the gaseous chlorine transport across a gas-permeable membrane that enables the establishment of a time-resolved analytical relationship to quantify chlorine concentration by multidata points with dramatically enhanced accuracy and reliability. A gas-permeable membrane-based portable colorimetric gaseous chlorine sensing probe (MCSP) was designed and fabricated. The MCSP embedded the proposed analytical principle that is capable of real-time continuous monitoring of the instantaneous and TWA chlorine gas concentrations within an analytical range of 0.009-2.058 mg L-1 without the need for on-going calibration, which could be a useful analytical tool for managing the toxic chlorine gas-imposed health risks in workplaces.


Assuntos
Cloro/química , Colorimetria/instrumentação , Colorimetria/métodos , Membranas Artificiais , Monitoramento Ambiental , Humanos , Exposição Ocupacional , Reprodutibilidade dos Testes
11.
Biosens Bioelectron ; 172: 112765, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33126179

RESUMO

To accurately diagnose COVID-19 infection and its time-dependent progression, the rapid, sensitive, and noninvasive determination of immunoglobulins A specific to SARS-CoV-2 (IgA) in saliva and serum is needed to complement tests that detect immunoglobulins G and M. We have developed a dual optical/chemiluminescence format of a lateral flow immunoassay (LFIA) immunosensor for IgA in serum and saliva. A recombinant nucleocapsid antigen specifically captures SARS-CoV-2 antibodies in patient specimens. A labelled anti-human IgA reveals the bound IgA fraction. A dual colorimetric and chemiluminescence detection enables the affordable and ultrasensitive determination of IgA to SARS-CoV-2. Specifically, a simple smartphone-camera-based device measures the colour signal provided by nanogold-labelled anti-human IgA. For the ultrasensitive chemiluminescence transduction, we used a contact imaging portable device based on cooled CCD, and measured the light signal resulting from the reaction of the HRP-labelled anti-human IgA with a H2O2/luminol/enhancers substrate. A total of 25 serum and 9 saliva samples from infected and/or recovered individuals were analysed by the colorimetric LFIA, which was sensitive and reproducible enough for the semi-quantification of IgA in subjects with a strong serological response and in the early stage of COVID-19 infection. Switching to CL detection, the same immunosensor exhibited higher detection capability, revealing the presence of salivary IgA in infected individuals. For the patients included in the study (n = 4), the level of salivary IgA correlated with the time elapsed from diagnosis and with the severity of the disease. This IgA-LFIA immunosensor could be useful for noninvasively monitoring early immune responses to COVID-19 and for investigating the diagnostic/prognostic utility of salivary IgA in the context of large-scale screening to assess the efficacy of SARS-CoV-2 vaccines.


Assuntos
Anticorpos Antivirais/análise , Técnicas Biossensoriais/instrumentação , Teste Sorológico para COVID-19/instrumentação , COVID-19/diagnóstico , SARS-CoV-2/imunologia , Especificidade de Anticorpos , Técnicas Biossensoriais/métodos , COVID-19/imunologia , COVID-19/virologia , Teste Sorológico para COVID-19/métodos , Colorimetria/instrumentação , Colorimetria/métodos , Desenho de Equipamento , Humanos , Imunoglobulina A/sangue , Imunoglobulina A Secretora/análise , Medições Luminescentes/instrumentação , Medições Luminescentes/métodos , Saliva/imunologia
12.
Food Chem ; 338: 127800, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32798815

RESUMO

For the first time, a method is proposed for colorimetric determination of reducing sugars in cachaça employing digital image and a smartphone as detector. The method was based on the reduction of Cu(II) to Cu(I) by sugars and followed by the formation of a colored Cu(I)-Neocuproine complex. A calibration curve was linear from 0.1 to 15 g L-1 for glucose and fructose with limits of detection of 0.012 g L-1 and 0.010 g L-1, respectively. It was observed that the non-aged cachaças, known for having inferior flavors and aromas, had a reducing sugar content three times higher than the aged cachaças, once a common practice among producers is to add sugar to adjust sensory deficits in the final product. Furthermore, the method is simple, does not require complex technical knowledge and it could be used as a tool to check possible fraud, adulteration or non-compliance to the law.


Assuntos
Bebidas Alcoólicas/análise , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Smartphone , Açúcares/análise , Colorimetria/instrumentação , Colorimetria/métodos , Cobre/química , Desenho de Equipamento , Contaminação de Alimentos/análise , Frutose/análise , Glucose/análise , Fenantrolinas/química , Saccharum
13.
Food Chem ; 335: 127566, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32745839

RESUMO

In this work, we developed an optical colorimetric sensor array for the discrimination of Chinese teas. The sensor array was carefully designed based on tea polyphenol induced indicators displacement assay (IDA), using phenylboronic acids with different substituents as the receptors to polyphenols. The accurate identification for polyphenols with different species or concentrations proved the potential of the sensor array. The sensor array successfully distinguished tea samples within different categories, grades and origins, coupling with PLS-DA. This work offered an efficient and rapid method to distinguish teas and tea-related products. Besides, the assay is supposed to be suitable for the identification of other polyphenol-related natural products.


Assuntos
Camellia sinensis/química , Colorimetria/instrumentação , Polifenóis/análise , Qualidade dos Alimentos , Limite de Detecção
14.
Food Chem ; 336: 127708, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32768908

RESUMO

Smartphone digital image colorimetry (SDIC), combined with solidification of floating organic drop-dispersive liquid-liquid microextraction (SFOD-DLLME), was proposed for the determination of iodate ions. A colorimetric box was designed to capture images of sample solutions. Factors affecting the efficiency of SDIC included type of phone, region of interest, position of camera, and distance between camera and sample solution. Optimum SFOD-DLLME conditions were achieved with 1-undecanol (500 µL) as the extraction solvent, ethanol (1.5 mL) as the disperser solvent within 20 s extraction time. Limit of detection (LOD) was found as 0.1 µM (0.2 µg g-1) and enrichment factors ranged between 17.4 and 25.0. Calibration graphs showed good linearity with coefficients of determination higher than 0.9954 and relative standard deviations lower than 5.6%. The proposed method was efficiently applied to determine iodate in table salt samples with percentage relative recoveries ranging between 89.3 and 109.3%.


Assuntos
Análise de Alimentos/métodos , Iodatos/análise , Microextração em Fase Líquida/métodos , Smartphone , Cloreto de Sódio na Dieta/análise , Calibragem , Colorimetria/instrumentação , Colorimetria/métodos , Análise de Alimentos/instrumentação , Processamento de Imagem Assistida por Computador , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Solventes/química
15.
PLoS Negl Trop Dis ; 14(9): e0008562, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32881914

RESUMO

BACKGROUND: Dengue is a systemic and dynamic disease with symptoms ranging from undifferentiated fever to dengue shock syndrome. Assessment of patients' severity of dehydration is integral to appropriate care and management. Urine colour has been shown to have a high correlation with overall assessment of hydration status. This study tests the feasibility of measuring dehydration severity in dengue fever patients by comparing urine colour captured by mobile phone cameras to established laboratory parameters. METHODOLOGY/PRINCIPAL FINDINGS: Photos of urine samples were taken in a customized photo booth, then processed using Adobe Photoshop to index urine colour into the red, green, and blue (RGB) colour space and assigned a unique RGB value. The RGB values were then correlated with patients' clinical and laboratory hydration indices using Pearson's correlation and multiple linear regression. There were strong correlations between urine osmolality and the RGB of urine colour, with r = -0.701 (red), r = -0.741 (green), and r = -0.761 (blue) (all p-value <0.05). There were strong correlations between urine specific gravity and the RGB of urine colour, with r = -0.759 (red), r = -0.785 (green), and r = -0.820 (blue) (all p-value <0.05). The blue component had the highest correlations with urine specific gravity and urine osmolality. There were moderate correlations between RGB components and serum urea, at r = -0.338 (red), -0.329 (green), -0.360 (blue). In terms of urine biochemical parameters linked to dehydration, multiple linear regression studies showed that the green colourimetry code was predictive of urine osmolality (ß coefficient -0.082, p-value <0.001) while the blue colourimetry code was predictive of urine specific gravity (ß coefficient -2,946.255, p-value 0.007). CONCLUSIONS/SIGNIFICANCE: Urine colourimetry using mobile phones was highly correlated with the hydration status of dengue patients, making it a potentially useful hydration status tool.


Assuntos
Telefone Celular , Colorimetria/métodos , Desidratação/urina , Dengue/urina , Urina/química , Adolescente , Adulto , Criança , Cor , Colorimetria/instrumentação , Estudos Transversais , Dengue/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
16.
Virus Res ; 288: 198129, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32822689

RESUMO

The COVID-19 pandemic caused by SARS-CoV-2 affects all aspects of human life. Detection platforms that are efficient, rapid, accurate, specific, sensitive, and user friendly are urgently needed to manage and control the spread of SARS-CoV-2. RT-qPCR based methods are the gold standard for SARS-CoV-2 detection. However, these methods require trained personnel, sophisticated infrastructure, and a long turnaround time, thereby limiting their usefulness. Reverse transcription-loop-mediated isothermal amplification (RT-LAMP), a one-step nucleic acid amplification method conducted at a single temperature, has been used for colorimetric virus detection. CRISPR-Cas12 and CRISPR-Cas13 systems, which possess collateral activity against ssDNA and RNA, respectively, have also been harnessed for virus detection. Here, we built an efficient, rapid, specific, sensitive, user-friendly SARS-CoV-2 detection module that combines the robust virus amplification of RT-LAMP with the specific detection ability of SARS-CoV-2 by CRISPR-Cas12. Furthermore, we combined the RT-LAMP-CRISPR-Cas12 module with lateral flow cells to enable highly efficient point-of-care SARS-CoV-2 detection. Our iSCAN SARS-CoV-2 detection module, which exhibits the critical features of a robust molecular diagnostic device, should facilitate the effective management and control of COVID-19.


Assuntos
Betacoronavirus/genética , Sistemas CRISPR-Cas , Técnicas de Laboratório Clínico/métodos , Colorimetria/métodos , Infecções por Coronavirus/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Pneumonia Viral/diagnóstico , Técnicas de Laboratório Clínico/instrumentação , Colorimetria/instrumentação , Infecções por Coronavirus/virologia , Endodesoxirribonucleases/química , Humanos , Técnicas de Diagnóstico Molecular/instrumentação , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Pandemias , Pneumonia Viral/virologia , Sistemas Automatizados de Assistência Junto ao Leito , Reologia , Sensibilidade e Especificidade
17.
Food Chem ; 332: 127431, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32645668

RESUMO

Illegal usage of ß-agonists as the animal growth promoters can lead to multiple harmful impacts to public health, thus detection of ß-agonists at trace level in complex sample matrixes is of great importance. In recent years, emergence of advanced nanomaterials greatly facilitates the advancement of sensors in terms of sensitivity, specificity and robustness. Plenty of nanoparticles-based sensors have been developed for ß-agonists determination. In this review, we comprehensively summarized the construction of emerging nanoparticles-based sensors (including colorimetric sensors, fluorescent sensors, chemiluminescent sensors, electrochemical sensors, electrochemiluminescent sensors, surface enhanced Raman scattering sensors, surface plasmon resonance sensors, quartz crystal microbalance sensors, etc.), and nanomaterial-based enzyme-linked immunosorbent assay (nano-ELISA). Impressively, the applications of nanoparticles-based sensors and nano-ELISAs in the detection of ß-agonists have also been summarized and discussed. In the end, future opportunities and challenges in the design construction of nanoparticles (NPs)-based sensors and their applications in ß-agonist assay are tentatively proposed.


Assuntos
Agonistas Adrenérgicos/análise , Nanoestruturas/química , Animais , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Colorimetria/instrumentação , Colorimetria/métodos , Humanos , Nanotecnologia/instrumentação , Nanotecnologia/métodos , Análise Espectral Raman/instrumentação , Análise Espectral Raman/métodos , Ressonância de Plasmônio de Superfície/instrumentação , Ressonância de Plasmônio de Superfície/métodos
18.
Food Chem ; 331: 127090, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32593035

RESUMO

Chlorothalonil is a class of 2B carcinogen which is widely used in the prevention and treatment of fungal diseases in food samples. Its residual problem has been increasingly concerned by society. In this paper, a fast and simple colorimetric assay based on Manganese dioxide nanosheets (MnO2 NSs)-oxidize 3,3',5,5'-tetramethylbenzidine (TMB) platform was used to detect residual pesticide chlorothalonil in food samples. Under optimal conditions, the half maximal inhibitory concentration and the limit of detection of chlorothalonil were 3.27 and 0.024 ng/mL. There were no obvious cross-reactivity between chlorothalonil and interference substances. The recoveries shown the satisfactory results. The results of colorimetric assay for the authentic samples were largely consistent with gas chromatography. Therefore, the proposed method would be convenient and satisfactory analytical methods for the monitoring of chlorothalonil. Furthermore, the MnO2 - TMB system was used to produce test strips for quick and convenient visual detection of chlorothalonil with good performance.


Assuntos
Colorimetria/métodos , Análise de Alimentos/métodos , Compostos de Manganês/química , Nanoestruturas/química , Nitrilas/análise , Óxidos/química , Benzidinas/química , Colorimetria/instrumentação , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Fungicidas Industriais/análise , Limite de Detecção , Oxirredução , Oxirredutases/química
19.
Anal Chim Acta ; 1113: 1-8, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32340664

RESUMO

Polygalacturonase (PG) activity in plants can serve as an important index for plant disease. However, the conventional method to detect PG activity is a complex process and requires a skilled technician and expensive analytical equipment. In this study, a paper-based colorimetric sensor was developed based on the principle of the ruthenium red (RR) dye method for easy and simple measurement of PG activity. The proposed paper-based sensor has a three-layer structure for detection of PG activity in samples. The sensor sensitivity was enhanced by optimizing the pH of the sodium acetate buffer used in polygalacturonic acid (PGA)-RR complex formation and the reaction temperature for PG and the PGA-RR complex. Further, for quantitative analysis of PG activity, Delta RGB analysis was conducted to detect color changes in the sensing window of the sensor. Results presented that the linear measurement range of the paper sensor was 0.02-0.1 unit with the limit of detection of 0.02 unit, which showed a similar detection range, but a lower detection limit, compared to the spectrophotometry. Furthermore, PG activity based on culture condition was measured using samples from Sclerotium cepivorum to verify the potential application of the developed paper-based sensor in the field. The measured activity showed no statistically significant difference from the values obtained from the spectrophotometry at 95% confidence level. Therefore, the paper-based colorimetric sensor can be used to predict plant diseases in Allium crops during the stage of pathogen invasion, potentially contributing to the improvement of crop production.


Assuntos
Papel , Doenças das Plantas/virologia , Poligalacturonase/análise , Ascomicetos/enzimologia , Colorimetria/instrumentação , Colorimetria/métodos , Limite de Detecção
20.
Ann Biol Clin (Paris) ; 78(2): 147-155, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32319943

RESUMO

OBJECTIVE: The aim of this study was to evaluate the analytical performance of the Alinity®c Abbott compared to the Architect® immunoassay system for the determination of drugs having a narrow therapeutic index. METHODS: Valproic acid, amikacin, gentamicin, phenobarbital and vancomycin were analyzed using Particle-Enhanced Turbidimetric Inhibitor Immunoassay (Petinia), phenytoin and theophylline were analyzed using an immunoenzymatic method and a colorimetric method was performed to quantify lithium. The methods were validated according to the total error approach. Seven validation standards were analyzed in quintuplet during four days to establish the limits of the methods. Dilution integrity and interferences (hemolysis and high concentrations of bilirubin and lipids) were also tested. Depending on the analyte, the results obtained for twenty to forty patients on the Alinity® were compared to those obtained on the Architect®. RESULTS: The bias and the coefficients of variation for repeatability and for intermediate precision were lower than 15% for all drugs. Accuracy profiles were acceptable (acceptance limits fixed at 30%) in the validated ranges. The lower limits of quantification (LLOQ) were similar to those determined by Abbott except for gentamicin for which we determined a LLOQ at 1.22 mg/L while Abbott determined it at 0.5 mg/L. All assays diluted linear and analyte concentrations were not affected by interferences. Concentrations obtained for real samples on the Alinity®c are comparable to those obtained on the Architect®ci. CONCLUSIONS: The analytical validation of a method suitable for therapeutic drug monitoring of drugs on the Alinity®c meets the requirements of European Medicines Agency.


Assuntos
Monitoramento de Medicamentos/instrumentação , Monitoramento de Medicamentos/métodos , Nefelometria e Turbidimetria/instrumentação , Nefelometria e Turbidimetria/métodos , Amicacina/análise , Amicacina/sangue , Automação Laboratorial/instrumentação , Automação Laboratorial/métodos , Colorimetria/instrumentação , Colorimetria/métodos , Gentamicinas/análise , Gentamicinas/sangue , Humanos , Imunoensaio/instrumentação , Imunoensaio/métodos , Fenobarbital/análise , Fenobarbital/sangue , Fenitoína/análise , Fenitoína/sangue , Reprodutibilidade dos Testes , Teofilina/análise , Teofilina/sangue , Ácido Valproico/análise , Ácido Valproico/sangue , Vancomicina/análise , Vancomicina/sangue
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