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1.
Nat Commun ; 11(1): 4405, 2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32879320

RESUMO

Active biofluid management is central to the realization of wearable bioanalytical platforms that are poised to autonomously provide frequent, real-time, and accurate measures of biomarkers in epidermally-retrievable biofluids (e.g., sweat). Accordingly, here, a programmable epidermal microfluidic valving system is devised, which is capable of biofluid sampling, routing, and compartmentalization for biomarker analysis. At its core, the system is a network of individually-addressable microheater-controlled thermo-responsive hydrogel valves, augmented with a pressure regulation mechanism to accommodate pressure built-up, when interfacing sweat glands. The active biofluid control achieved by this system is harnessed to create unprecedented wearable bioanalytical capabilities at both the sensor level (decoupling the confounding influence of flow rate variability on sensor response) and the system level (facilitating context-based sensor selection/protection). Through integration with a wireless flexible printed circuit board and seamless bilateral communication with consumer electronics (e.g., smartwatch), contextually-relevant (scheduled/on-demand) on-body biomarker data acquisition/display was achieved.


Assuntos
Biomarcadores/análise , Técnicas Analíticas Microfluídicas/métodos , Microfluídica , Técnicas Biossensoriais , Epiderme/química , Humanos , Suor/química , Dispositivos Eletrônicos Vestíveis
2.
Nat Commun ; 11(1): 4489, 2020 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-32895384

RESUMO

We report a covalent chemistry-based hepatocellular carcinoma (HCC)-specific extracellular vesicle (EV) purification system for early detection of HCC by performing digital scoring on the purified EVs. Earlier detection of HCC creates more opportunities for curative therapeutic interventions. EVs are present in circulation at relatively early stages of disease, providing potential opportunities for HCC early detection. We develop an HCC EV purification system (i.e., EV Click Chips) by synergistically integrating covalent chemistry-mediated EV capture/release, multimarker antibody cocktails, nanostructured substrates, and microfluidic chaotic mixers. We then explore the translational potential of EV Click Chips using 158 plasma samples of HCC patients and control cohorts. The purified HCC EVs are subjected to reverse-transcription droplet digital PCR for quantification of 10 HCC-specific mRNA markers and computation of digital scoring. The HCC EV-derived molecular signatures exhibit great potential for noninvasive early detection of HCC from at-risk cirrhotic patients with an area under receiver operator characteristic curve of 0.93 (95% CI, 0.86 to 1.00; sensitivity = 94.4%, specificity = 88.5%).


Assuntos
Biomarcadores Tumorais/isolamento & purificação , Carcinoma Hepatocelular/diagnóstico , Detecção Precoce de Câncer/métodos , Vesículas Extracelulares/genética , Neoplasias Hepáticas/diagnóstico , Idoso , Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/sangue , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Estudos de Casos e Controles , Química Click/instrumentação , Química Click/métodos , Química Computacional , Simulação por Computador , Diagnóstico Diferencial , Dimetilpolisiloxanos/química , Progressão da Doença , Detecção Precoce de Câncer/instrumentação , Feminino , Células Hep G2 , Humanos , Dispositivos Lab-On-A-Chip , Biópsia Líquida/instrumentação , Biópsia Líquida/métodos , Cirrose Hepática/sangue , Cirrose Hepática/patologia , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Masculino , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Pessoa de Meia-Idade , Nanoestruturas/química , Nanofios/química , Estadiamento de Neoplasias , RNA Mensageiro/genética , RNA Mensageiro/isolamento & purificação , Curva ROC , Reação em Cadeia da Polimerase Via Transcriptase Reversa/instrumentação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos
4.
Anal Chem ; 92(14): 9454-9458, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32615038

RESUMO

The outbreak of SARS-CoV-2 is posing serious global public health problems. Facing the emergence of this pandemic, we established a portable microfluidic immunoassay system for easy-to-use, sensitive, rapid (<15 min), multiple, and on-site detection of IgG/IgM/Antigen of SARS-CoV-2 simultaneously. This integrated method was successfully applied for detecting SARS-CoV-2 IgM and IgG antibodies in clinical human serum as well as SARS-CoV-2 antigen in pharyngeal swabs from 26 patients with COVID-19 infection and 28 uninfected people. The assay demonstrated high sensitivity and specificity, which is promising for the diagnosis and monitoring as well as control of SARS-CoV-2 worldwide.


Assuntos
Anticorpos Antivirais/análise , Betacoronavirus/imunologia , Infecções por Coronavirus/diagnóstico , Imunoensaio/métodos , Imunoglobulina G/análise , Imunoglobulina M/análise , Técnicas Analíticas Microfluídicas/métodos , Pneumonia Viral/diagnóstico , Técnicas de Laboratório Clínico/métodos , Ensaio de Imunoadsorção Enzimática , Humanos , Pandemias , Faringe/química , Faringe/imunologia , Sensibilidade e Especificidade
5.
PLoS One ; 15(6): e0233239, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32516315

RESUMO

Foodborne contamination and associated illness in the United States is responsible for an estimated 48 million cases per year. Increased food demand, global commerce of perishable foods, and the growing threat of antibiotic resistance are driving factors elevating concern for food safety. Foodborne illness is often associated with fresh-cut, ready-to-eat produce commodities due to the perishable nature of the product and relatively minimal processing from farm to the consumer. The research presented here optimizes and evaluates the utility of microfluidic droplets, also termed ultra-miniaturized bioreactors, for rapid detection of viable Salmonella enterica ser. Typhimurium in a shredded lettuce wash water acquired from a major Mid-Atlantic produce processing facility (denoted as Producer) in the U.S. Using a fluorescently-labeled anti-S. Typhimurium antibody and relative fluorescence intensities, paired with in-droplet incubation, S. Typhimurium was detected and identified with 100% specificity in less than 5 h. In initial optimization experiments using S. Typhimurium-spiked sterile water, the relative fluorescence intensity of S. Typhimurium was approximately two times that of the observed relative intensities of five non-S. Typhimurium negative controls at 4-h incubation in droplets containing Rappaport-Vasiliadis (RV) broth at 37°C: relative fluorescence intensity for S. Typhimurium = 2.36 (95% CI: 2.15-2.58), Enterobacter aerogens 1.12 (95% CI: 1.09-1.16), Escherichia coli 700609 = 1.13 (95% CI: 1.09-1.17), E. coli 13706 1.13 (95% CI: 1.07-1.19), E. coli 700891 1.05 (95% CI: 1.03-1.07) and Citrobacter freundii 1.04 (95% CI: 1.03-1.05). S. Typhimurium- and E. aerogens-spiked shredded lettuce wash waters acquired from the Producer were then incubated 4 h in-droplet at 37°C with RV broth. The observed relative fluorescence of S. Typhimurium was significantly higher than that of E. aerogens, 1.56 (95% CI: 1.42-1.71) and 1.10 (95% CI: 1.08-1.12), respectively. While further optimization focusing on compatible concentration methodologies for highly-dilute produce water samples is needed, this application of droplet microfluidics shows great promise in dramatically shortening the time necessary-from days to hours-to confirm viable bacterial contamination in ready-to-eat produce wash waters used throughout the domestic and international food industry.


Assuntos
Microbiologia de Alimentos/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Técnicas Analíticas Microfluídicas/métodos , Cloro/análise , Citrobacter freundii , Contagem de Colônia Microbiana , Desinfetantes , Escherichia coli O157 , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Indústria de Processamento de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Microfluídica/métodos , Salmonella typhimurium
6.
Nat Commun ; 11(1): 2982, 2020 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-32532969

RESUMO

Non-invasive and label-free calorimetry could become a disruptive technique to study single cell metabolic heat production without altering the cell behavior, but it is currently limited by insufficient sensitivity. Here, we demonstrate microfluidic single-cell calorimetry with 0.2-nW sensitivity, representing more than ten-fold enhancement over previous record, which is enabled by (i) a low-noise thermometry platform with ultralow long-term (10-h) temperature noise (80 µK) and (ii) a microfluidic channel-in-vacuum design allowing cell flow and nutrient delivery while maintaining a low thermal conductance of 2.5 µW K-1. Using Tetrahymena thermophila as an example, we demonstrate on-chip single-cell calorimetry measurement with metabolic heat rates ranging from 1 to 4 nW, which are found to correlate well with the cell size. Finally, we perform real-time monitoring of metabolic rate stimulation by introducing a mitochondrial uncoupling agent to the microchannel, enabling determination of the spare respiratory capacity of the cells.


Assuntos
Calorimetria/métodos , Técnicas Analíticas Microfluídicas/métodos , Microfluídica/métodos , Análise de Célula Única/métodos , Temperatura , Tetrahymena thermophila/metabolismo , Metabolismo Basal , Calorimetria/instrumentação , Microfluídica/instrumentação , Mitocôndrias/metabolismo , Consumo de Oxigênio , Análise de Célula Única/instrumentação , Tetrahymena thermophila/citologia , Condutividade Térmica
7.
Nat Commun ; 11(1): 2385, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32404937

RESUMO

Upon tissue injury or microbial invasion, a large number of neutrophils converge from blood to the sites of injury or infection in a short time. The migration through a limited number of paths through tissues and capillary networks seems efficient and 'traffic jams' are generally avoided. However, the mechanisms that guide efficient trafficking of large numbers of neutrophils through capillary networks are not well understood. Here we show that pairs of neutrophils arriving closely one after another at capillary bifurcations migrate to alternating branches in vivo and in vitro. Perturbation of chemoattractant gradients and the increased hydraulic resistance induced by the first neutrophil in one branch biases the migration of the following neutrophil towards the other branch. These mechanisms guide neutrophils to efficiently navigate through capillary networks and outline the effect of inter-neutrophil interactions during migration on overall lymphocyte trafficking patterns in confined environments.


Assuntos
Movimento Celular/fisiologia , Fatores Quimiotáticos/metabolismo , Quimiotaxia/fisiologia , Técnicas Analíticas Microfluídicas/métodos , Neutrófilos/fisiologia , Algoritmos , Células Cultivadas , Humanos , Modelos Biológicos , Neutrófilos/citologia , Transdução de Sinais/fisiologia
8.
Nat Commun ; 11(1): 2190, 2020 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-32366850

RESUMO

Microfluidics by soft lithography has proven to be of key importance for biophysics and life science research. While being based on replicating structures of a master mold using benchtop devices, design modifications are time consuming and require sophisticated cleanroom equipment. Here, we introduce virtual fluidic channels as a flexible and robust alternative to microfluidic devices made by soft lithography. Virtual channels are liquid-bound fluidic systems that can be created in glass cuvettes and tailored in three dimensions within seconds for rheological studies on a wide size range of biological samples. We demonstrate that the liquid-liquid interface imposes a hydrodynamic stress on confined samples, and the resulting strain can be used to calculate rheological parameters from simple linear models. In proof-of-principle experiments, we perform high-throughput rheology inside a flow cytometer cuvette and show the Young's modulus of isolated cells exceeds the one of the corresponding tissue by one order of magnitude.


Assuntos
Dimetilpolisiloxanos/química , Módulo de Elasticidade/fisiologia , Técnicas Analíticas Microfluídicas/métodos , Microfluídica/métodos , Polietilenoglicóis/química , Algoritmos , Desenho de Equipamento , Citometria de Fluxo , Células HEK293 , Células HL-60 , Humanos , Hidrodinâmica , Técnicas Analíticas Microfluídicas/instrumentação , Microfluídica/instrumentação , Modelos Teóricos , Reologia , Esferoides Celulares
9.
Nature ; 582(7811): 277-282, 2020 06.
Artigo em Inglês | MEDLINE | ID: covidwho-164175

RESUMO

The great majority of globally circulating pathogens go undetected, undermining patient care and hindering outbreak preparedness and response. To enable routine surveillance and comprehensive diagnostic applications, there is a need for detection technologies that can scale to test many samples1-3 while simultaneously testing for many pathogens4-6. Here, we develop Combinatorial Arrayed Reactions for Multiplexed Evaluation of Nucleic acids (CARMEN), a platform for scalable, multiplexed pathogen detection. In the CARMEN platform, nanolitre droplets containing CRISPR-based nucleic acid detection reagents7 self-organize in a microwell array8 to pair with droplets of amplified samples, testing each sample against each CRISPR RNA (crRNA) in replicate. The combination of CARMEN and Cas13 detection (CARMEN-Cas13) enables robust testing of more than 4,500 crRNA-target pairs on a single array. Using CARMEN-Cas13, we developed a multiplexed assay that simultaneously differentiates all 169 human-associated viruses with at least 10 published genome sequences and rapidly incorporated an additional crRNA to detect the causative agent of the 2020 COVID-19 pandemic. CARMEN-Cas13 further enables comprehensive subtyping of influenza A strains and multiplexed identification of dozens of HIV drug-resistance mutations. The intrinsic multiplexing and throughput capabilities of CARMEN make it practical to scale, as miniaturization decreases reagent cost per test by more than 300-fold. Scalable, highly multiplexed CRISPR-based nucleic acid detection shifts diagnostic and surveillance efforts from targeted testing of high-priority samples to comprehensive testing of large sample sets, greatly benefiting patients and public health9-11.


Assuntos
Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Técnicas Analíticas Microfluídicas/métodos , Viroses/diagnóstico , Viroses/virologia , Animais , Betacoronavirus/genética , Betacoronavirus/isolamento & purificação , Farmacorresistência Viral/genética , Genoma Viral/genética , HIV/classificação , HIV/genética , HIV/isolamento & purificação , Humanos , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Técnicas Analíticas Microfluídicas/instrumentação , RNA Guia/genética , Sensibilidade e Especificidade
10.
Transfusion ; 60(5): 1032-1041, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32237236

RESUMO

BACKGROUND: Great deformability allows red blood cells (RBCs) to flow through narrow capillaries in tissues. A number of microfluidic devices with capillary-like microchannels have been developed to monitor storage-related impairment of RBC deformability during blood banking operations. This proof-of-concept study describes a new method to standardize and improve reproducibility of the RBC deformability measurements using one of these devices. STUDY DESIGN AND METHODS: The rate of RBC flow through the microfluidic capillary network of the microvascular analyzer (MVA) device made of polydimethylsiloxane was measured to assess RBC deformability. A suspension of microbeads in a solution of glycerol in phosphate-buffered saline was developed to be used as an internal flow rate reference alongside RBC samples in the same device. RBC deformability and other in vitro quality markers were assessed weekly in six leukoreduced RBC concentrates (RCCs) dispersed in saline-adenine-glucose-mannitol additive solution and stored over 42 days at 4°C. RESULTS: The use of flow reference reduced device-to-device measurement variability from 10% to 2%. Repeated-measure analysis using the generalized estimating equation (GEE) method showed a significant monotonic decrease in relative RBC flow rate with storage from Week 0. By the end of storage, relative RBC flow rate decreased by 22 ± 6% on average. CONCLUSIONS: The suspension of microbeads was successfully used as a flow reference to increase reproducibility of RBC deformability measurements using the MVA. Deformability results suggest an early and late aging phase for stored RCCs, with significant decreases between successive weeks suggesting a highly sensitive measurement method.


Assuntos
Deformação Eritrocítica/fisiologia , Eritrócitos/citologia , Eritrócitos/fisiologia , Dispositivos Lab-On-A-Chip/normas , Técnicas Analíticas Microfluídicas , Bancos de Sangue/métodos , Bancos de Sangue/normas , Velocidade do Fluxo Sanguíneo/fisiologia , Preservação de Sangue/efeitos adversos , Preservação de Sangue/métodos , Preservação de Sangue/normas , Criopreservação , Contagem de Eritrócitos/instrumentação , Contagem de Eritrócitos/métodos , Contagem de Eritrócitos/normas , Citometria de Fluxo/instrumentação , Citometria de Fluxo/métodos , Citometria de Fluxo/normas , Hemólise , Humanos , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Técnicas Analíticas Microfluídicas/normas , Estudo de Prova de Conceito , Reprodutibilidade dos Testes , Fatores de Tempo
11.
Nature ; 582(7811): 277-282, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32349121

RESUMO

The great majority of globally circulating pathogens go undetected, undermining patient care and hindering outbreak preparedness and response. To enable routine surveillance and comprehensive diagnostic applications, there is a need for detection technologies that can scale to test many samples1-3 while simultaneously testing for many pathogens4-6. Here, we develop Combinatorial Arrayed Reactions for Multiplexed Evaluation of Nucleic acids (CARMEN), a platform for scalable, multiplexed pathogen detection. In the CARMEN platform, nanolitre droplets containing CRISPR-based nucleic acid detection reagents7 self-organize in a microwell array8 to pair with droplets of amplified samples, testing each sample against each CRISPR RNA (crRNA) in replicate. The combination of CARMEN and Cas13 detection (CARMEN-Cas13) enables robust testing of more than 4,500 crRNA-target pairs on a single array. Using CARMEN-Cas13, we developed a multiplexed assay that simultaneously differentiates all 169 human-associated viruses with at least 10 published genome sequences and rapidly incorporated an additional crRNA to detect the causative agent of the 2020 COVID-19 pandemic. CARMEN-Cas13 further enables comprehensive subtyping of influenza A strains and multiplexed identification of dozens of HIV drug-resistance mutations. The intrinsic multiplexing and throughput capabilities of CARMEN make it practical to scale, as miniaturization decreases reagent cost per test by more than 300-fold. Scalable, highly multiplexed CRISPR-based nucleic acid detection shifts diagnostic and surveillance efforts from targeted testing of high-priority samples to comprehensive testing of large sample sets, greatly benefiting patients and public health9-11.


Assuntos
Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Técnicas Analíticas Microfluídicas/métodos , Viroses/diagnóstico , Viroses/virologia , Animais , Betacoronavirus/genética , Betacoronavirus/isolamento & purificação , Farmacorresistência Viral/genética , Genoma Viral/genética , HIV/classificação , HIV/genética , HIV/isolamento & purificação , Humanos , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Técnicas Analíticas Microfluídicas/instrumentação , RNA Guia/genética , Sensibilidade e Especificidade
12.
PLoS Negl Trop Dis ; 14(2): e0008082, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32069280

RESUMO

BACKGROUND: Dengue virus (DENV) is the most important arbovirus worldwide, causing infections in endemic countries and returning travellers from these areas. Rapid diagnostic tests are needed to improve patient management and monitor local transmission. The detection of DENV non-structural protein 1 (NS1) is a useful tool for the diagnosis, but the currently available methods can be time consuming or lack sensitivity. The objective of our study was to evaluate a new rapid and semi-quantitative microfluidic DENV NS1 immuno-magnetic agglutination assay based on aggregation of magnetic nanoparticles detected by an electronic reader (Virotrack Dengue Acute and Blubox, Blusense diagnostics, Copenhagen, Denmark). METHODOLOGY/PRINCIPAL FINDINGS: A panel of 135 serum samples from travelers returning from dengue endemic countries was analyzed (74 DENV positive samples including the four DENV serotypes, 26 Zika virus positive samples, 25 chikungunya virus positive samples, 5 malaria positive samples and 5 negative samples). Samples were tested by three different antigen detection methods: SD Dengue NS1 Ag ELISA, SD BIOLINE Dengue Duo and ViroTrack Dengue Acute. The sensitivity observed for SD Dengue NS1 Ag ELISA, ViroTrack Dengue Acute and SD BIOLINE Dengue Duo was 97.2%, 91.1% and 68.1%, respectively. All methods showed high specificity (98.4% for ViroTrack Dengue Acute and 100% for both SD Dengue NS1 Ag ELISA and SD BIOLINE Dengue Duo). SD Dengue NS1 Ag ELISA and ViroTrack Dengue Acute only failed to detect samples positive for DENV-2. CONCLUSIONS/SIGNIFICANCE: ViroTrack Dengue Acute is a sensitive and specific assay for DENV NS1 detection. It provides faster results than the ELISA method and a better performance than the rapid immunochromatographic tests. ViroTrack Dengue Acute could represent a valuable tool for rapid diagnosis of DENV infections in returning travellers from endemic countries.


Assuntos
Antígenos Virais/isolamento & purificação , Vírus da Dengue/metabolismo , Separação Imunomagnética/métodos , Técnicas Analíticas Microfluídicas/métodos , Proteínas não Estruturais Virais/química , Vírus da Dengue/classificação , Proteínas não Estruturais Virais/metabolismo
13.
PLoS One ; 15(2): e0223932, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32107504

RESUMO

The measurement of the proliferation (and the relevant inhibition of proliferation) of microbes is used in different settings, from industry to laboratory medicine. Thus, in this study, the capacity of the Antibiochip (ELTEK spa), a microfluidic-based device, to measure the amount of E. coli in certain culture conditions, was evaluated. An Antibiochip is composed of V-shaped microchannels, and the amount of microparticles (such as microbes) is measured by the surface of the pellet after centrifugation. In the present study, different geometries, volumes and times were analyzed. When the best conditions were identified, serial dilutions of microbial cultures were tested to validate the linearity of the results. Then, with the use of wild E. coli strains isolated from medical samples, the relationship between bacterial susceptibility to antibiotics measured by standard methods and that measured by the Antibiochip was evaluated. In this report, the good quality performances of the methods, their linearity and the capacity to identify susceptible microbial strains after 60 minutes of incubation are shown. These results represent a novel approach for ultrarapid antibiograms in clinics.


Assuntos
Bactérias/citologia , Proliferação de Células/efeitos dos fármacos , Dispositivos Lab-On-A-Chip , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Técnicas Analíticas Microfluídicas/métodos
14.
J Food Sci ; 85(3): 736-743, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32017096

RESUMO

By utilizing the coffee-ring effect and microfluidic paper-based analytical devices (µPADs), this study improved the sensitivity of the determination of norfloxacin in four different food matrices. Micro-PADs in this study were fabricated by designing and embedding wax channels onto cellulose-based filter paper through printing and subjecting the paper to heat to allow the wax to penetrate the paper. Determination of norfloxacin concentration in food samples was achieved by monitoring the colorimetric reaction that occurred between norfloxacin and the added iron (III) nitrate nonahydrate in 5 mM ammonia in each reaction chamber. A transition metal hydroxide was formed through this reaction that resulted in the formation of a solid precipitate to enable the antibiotic to bind to the iron molecule via coordination chemistry. This metal ion-antibiotic complex generated a visible color change. Following the colorimetric reaction, images were taken and subsequently analyzed via ImageJ to determine the relative pixel intensity that was used to infer norfloxacin concentration. The analytical sensitivity of this device was determined to be as low as 50 ppm when analyzing the inner-ring reaction, and as low as 5 ppm when analyzing the outer coffee ring thereby allowing for an alternative cheaper, faster, and more user-friendly method to detect norfloxacin than the conventional methods. PRACTICAL APPLICATION: This novel paper-based microfluidic device can achieve the detection of antibiotic residues in agrifoods in a faster, cheaper, and more user-friendly manner.


Assuntos
Antibacterianos/análise , Resíduos de Drogas/análise , Técnicas Analíticas Microfluídicas/métodos , Norfloxacino/análise , Colorimetria , Contaminação de Alimentos/análise , Técnicas Analíticas Microfluídicas/instrumentação , Smartphone
15.
Biosensors (Basel) ; 10(2)2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32059538

RESUMO

Infections pose a serious global public health problem and are a major cause of premature mortality worldwide. One of the most challenging objectives faced by modern medicine is timely and accurate laboratory-based diagnostics of infectious diseases. Being a key factor of timely initiation and success of treatment, it may potentially provide reduction in incidence of a disease, as well as prevent outbreak and spread of dangerous epidemics. The traditional methods of laboratory-based diagnostics of infectious diseases are quite time- and labor-consuming, require expensive equipment and qualified personnel, which restricts their use in case of limited resources. Over the past six decades, diagnostic technologies based on lateral flow immunoassay (LFIA) have been and remain true alternatives to modern laboratory analyzers and have been successfully used to quickly detect molecular ligands in biosubstrates to diagnose many infectious diseases and septic conditions. These devices are considered as simplified formats of modern biosensors. Recent advances in the development of label-free biosensor technologies have made them promising diagnostic tools that combine rapid pathogen indication, simplicity, user-friendliness, operational efficiency, accuracy, and cost effectiveness, with a trend towards creation of portable platforms. These qualities exceed the generally accepted standards of microbiological and immunological diagnostics and open up a broad range of applications of these analytical systems in clinical practice immediately at the site of medical care (point-of-care concept, POC). A great variety of modern nanoarchitectonics of biosensors are based on the use of a broad range of analytical and constructive strategies and identification of various regulatory and functional molecular markers associated with infectious bacterial pathogens. Resolution of the existing biosensing issues will provide rapid development of diagnostic biotechnologies.


Assuntos
Técnicas Biossensoriais/métodos , Doenças Transmissíveis/diagnóstico , Técnicas Analíticas Microfluídicas/métodos , Humanos
16.
PLoS One ; 15(1): e0227294, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31940389

RESUMO

BACKGROUND: Cell-free DNA detection is becoming a surrogate assay for tumor genotyping. Biological fluids often content a very low amount of cell-free tumor DNA and assays able to detect very low allele frequency mutant with a few quantities of DNA are required. We evaluated the ability of the fully-automated molecular diagnostics platform Idylla for the detection of KRAS, NRAS and BRAF hotspot mutations in plasma from patients with metastatic colorectal cancer (mCRC). MATERIALS AND METHODS: First, we evaluated the limit of detection of the system using two set of laboratory made samples that mimic mCRC patient plasma, then plasma samples from patients with mCRC were assessed using Idylla system and BEAMing digital PCR technology. RESULTS: Limits of detection of 0.1%, 0.4% and 0.01% for KRAS, NRAS and BRAF respectively have been reached. With our laboratory made samples, sensitivity up to 0.008% has been reached. Among 15 patients' samples tested for KRAS mutation, 2 discrepant results were found between Idylla and BEAMing dPCR. A 100% concordance between the two assays has been found for the detection of NRAS and BRAF mutations in plasma samples. CONCLUSIONS: The Idylla system does not reach as high sensitivity as assays like ddPCR but has an equivalent sensitivity to modified NGS technics with a lower cost and a lower time to results. These data allowed to consider the Idylla system in a routine laboratory workflow for KRAS, NRAS and BRAF mutations detection in plasma.


Assuntos
Biomarcadores Tumorais/genética , DNA Tumoral Circulante/isolamento & purificação , Neoplasias Colorretais/diagnóstico , Análise Mutacional de DNA/instrumentação , Técnicas de Genotipagem/instrumentação , Linhagem Celular Tumoral , DNA Tumoral Circulante/genética , Ensaios Clínicos como Assunto , Neoplasias Colorretais/genética , Análise Mutacional de DNA/métodos , GTP Fosfo-Hidrolases/genética , Frequência do Gene , Técnicas de Genotipagem/métodos , Humanos , Limite de Detecção , Proteínas de Membrana/genética , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Sensibilidade e Especificidade
17.
Sci Rep ; 10(1): 1251, 2020 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-31988339

RESUMO

Separating specific cell phenotypes from a heterotypic mixture is a critical step in many research projects. Traditional methods usually require a large sample volume and a complex preparation process that may alter cell property during the sorting process. Here we present the use of electrical impedance as an indicator of cell health and for identifying specific microalgal phenotypes. We developed a microfluidic platform for measuring electrical impedance at different frequencies using the bacterium-sized green alga Picochlorum SE3. The cells were cultured under different salinity conditions and sampled at four different time points. Our results demonstrate the utility of electrical impedance as an indicator of cell phenotype by providing results that are consistent with known changes in cell size and physiology. Outliers in the cell data distribution are particularly useful because they represent phenotypes that have the ability to maintain size and/or membrane ionic permeability under prolonged salt stress. This suggests that our device can be used to identify and sort desired (e.g., experimentally evolved, mutant) cell phenotypes based on their electrical impedance properties.


Assuntos
Microalgas/citologia , Microalgas/isolamento & purificação , Técnicas Analíticas Microfluídicas/métodos , Técnicas Biossensoriais/métodos , Separação Celular/métodos , Técnicas Citológicas/métodos , Impedância Elétrica , Genômica/métodos , Microalgas/metabolismo , Análise de Célula Única/métodos
18.
Nat Methods ; 17(1): 86-92, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31740817

RESUMO

Our ability to connect genotypic variation to biologically important phenotypes has been seriously limited by the gap between live-cell microscopy and library-scale genomic engineering. Here, we show how in situ genotyping of a library of strains after time-lapse imaging in a microfluidic device overcomes this problem. We determine how 235 different CRISPR interference knockdowns impact the coordination of the replication and division cycles of Escherichia coli by monitoring the location of replication forks throughout on average >500 cell cycles per knockdown. Subsequent in situ genotyping allows us to map each phenotype distribution to a specific genetic perturbation to determine which genes are important for cell cycle control. The single-cell time-resolved assay allows us to determine the distribution of single-cell growth rates, cell division sizes and replication initiation volumes. The technology presented in this study enables genome-scale screens of most live-cell microscopy assays.


Assuntos
Sistemas CRISPR-Cas , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Processamento de Imagem Assistida por Computador/métodos , Engenharia Metabólica/métodos , Técnicas Analíticas Microfluídicas/métodos , Microscopia/métodos , Ciclo Celular , Replicação do DNA , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Proteínas de Escherichia coli/antagonistas & inibidores , Proteínas de Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica , Biblioteca Gênica , Genótipo , Fenótipo
19.
J Chromatogr A ; 1610: 460539, 2020 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-31543341

RESUMO

Over the past decade significant progress has been found in the upstream production processes, shifting the main bottlenecks in current manufacturing platforms for biopharmaceuticals towards the downstream processing. Challenges in the purification process include reducing the production costs, developing robust and efficient purification processes as well as integrating both upstream and downstream processes. Microfluidic technologies have recently emerged as effective tools for expediting bioprocess design in a cost-effective manner, since a large number of variables can be evaluated in a small time frame, using reduced volumes and manpower. Their modularity also allows to integrate different unit operations into a single chip, and consequently to evaluate the effect of each stage on the overall process efficiency. This paper describes the development of a diffusion-based microfluidic device for the rapid screening of continuous chemical lysis conditions. The release of a recombinant green fluorescent protein (GFP) expressed in Escherichia coli (E. coli) was used as model system due to the simple evaluation of cell growth and product concentration by fluorescence. The concept can be further applied to any biopharmaceutical production platform. The microfluidic device was successfully used to test the lytic effect of both enzymatic and chemical lysis solutions, with lysis efficiency of about 60% and close to 100%, respectively, achieved. The microfluidic technology also demonstrated the ability to detect potential process issues, such as the increased viscosity related with the rapid release of genomic material, that can arise for specific lysis conditions and hinder the performance of a bioprocess. Finally, given the continuous operation of the lysis chip, the microfluidic technology has the potential to be integrated with other microfluidic modules in order to model a fully continuous biomanufacturing process on a chip.


Assuntos
Bactérias , Técnicas Analíticas Microfluídicas , Proteínas Recombinantes , Bactérias/química , Bactérias/citologia , Bactérias/metabolismo , Proteínas de Fluorescência Verde/análise , Proteínas de Fluorescência Verde/metabolismo , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Proteínas Recombinantes/análise , Proteínas Recombinantes/metabolismo
20.
Talanta ; 206: 120200, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514845

RESUMO

Highly-sensitive and contamination-free droplet digital PCR (ddPCR) is an enabling technology and widely needed for accurate quantification of nucleic acid in clinical applications. In this paper, a novel droplet reader was developed by combining a "quasi" confocal laser-induced fluorescence (LIF) cytometry with a delicate microfluidic chip design. The droplets with a size of 90 µm was illuminated at an out-of-focus position by two aligned laser beams to generate maximum fluorescent signal. Additionally, the lateral offset position of the microfluidic chip should be precisely tuned so that the bandwidth of the FAM and VIC channels were configured at the matching sizes. Then, PMT gain voltages and pneumatic pressures were optimized for better droplet detection efficiencies. An aerosol adsorption experiment was performed to demonstrate that there was no aerosol contamination, and detected copy numbers of both mutants and wild types scaled linearly with the expected input copy numbers (r2>0.998) with a LoB of 0.0 copies and LoD of 3.0 copies. The results demonstrated that this droplet reader with the delicate chip is a convenient, highly-sensitive and contamination-free to detect fluorescence signals inside droplets after ddPCR, which is highly promising for broad applications of ddPCR in clinical diagnosis.


Assuntos
DNA/análise , Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/métodos , Reação em Cadeia da Polimerase/métodos , Desenho de Equipamento , Receptores ErbB/genética , Antígeno HLA-B27/genética , Limite de Detecção , Técnicas Analíticas Microfluídicas/instrumentação , Mutação , Reação em Cadeia da Polimerase/instrumentação
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