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1.
Nat Protoc ; 16(4): 2158-2189, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33790475

RESUMEN

Owing to their high spatiotemporal precision and adaptability to different host cells, organ-on-a-chip systems are showing great promise in drug discovery, developmental biology studies and disease modeling. However, many current micro-engineered biomimetic systems are limited in technological application because of culture media mixing that does not allow direct incorporation of techniques from stem cell biology, such as organoids. Here, we describe a detailed alternative method to cultivate millimeter-scale functional vascularized tissues on a biofabricated platform, termed 'integrated vasculature for assessing dynamic events', that enables facile incorporation of organoid technology. Utilizing the 3D stamping technique with a synthetic polymeric elastomer, a scaffold termed 'AngioTube' is generated with a central microchannel that has the mechanical stability to support a perfusable vascular system and the self-assembly of various parenchymal tissues. We demonstrate an increase in user familiarity and content analysis by situating the scaffold on a footprint of a 96-well plate. Uniquely, the platform can be used for facile connection of two or more tissue compartments in series through a common vasculature. Built-in micropores enable the studies of cell invasion involved in both angiogenesis and metastasis. We describe how this protocol can be applied to create both vascularized cardiac and hepatic tissues, metastatic breast cancer tissue and personalized pancreatic cancer tissue through incorporation of patient-derived organoids. Platform assembly to populating the scaffold with cells of interest into perfusable functional vascularized tissue will require 12-14 d and an additional 4 d if pre-polymer and master molds are needed.


Asunto(s)
Vasos Sanguíneos/fisiología , Dispositivos Laboratorio en un Chip , Organoides/fisiología , Perfusión , Células Endoteliales de la Vena Umbilical Humana/citología , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Andamios del Tejido/química
2.
Sci Rep ; 11(1): 9277, 2021 04 29.
Artículo en Inglés | MEDLINE | ID: mdl-33927298

RESUMEN

Label-free optical biosensors have received tremendous attention in point-of-care testing, especially in the emerging pandemic, COVID-19, since they advance toward early-detection, rapid, real-time, ease-of-use, and low-cost paradigms. Protein biomarkers testings require less sample modification process compared to nucleic-acid biomarkers'. However, challenges always are in detecting low-concentration for early-stage diagnosis. Here we present a Rotationally Focused Flow (RFF) method to enhance sensitivity(wavelength shift) of label-free optical sensors by increasing the detection probability of protein-based molecules. The RFF is structured by adding a less-dense fluid to focus the target-fluid in a T-shaped microchannel. It is integrated with label-free silicon microring resonators interacting with biotin-streptavidin. The suggested mechanism has demonstrated 0.19 fM concentration detection along with a significant magnitudes sensitivity enhancement compared to single flow methods. Verified by both CFD simulations and fluorescent flow-experiments, this study provides a promising proof-of-concept platform for next-generation lab-on-a-chip bioanalytics such as ultrafast and early-detection of COVID-19.


Asunto(s)
/diagnóstico , Microfluídica/métodos , /fisiología , Biomarcadores/metabolismo , Técnicas Biosensibles , Diagnóstico Precoz , Humanos , Dispositivos Laboratorio en un Chip , Sensibilidad y Especificidad
3.
Sensors (Basel) ; 21(8)2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33921116

RESUMEN

This paper presents a compact spectral detection system for common fluorescent and colorimetric assays. This system includes a gradient grating period guided-mode resonance (GGP-GMR) filter and charge-coupled device. In its current form, the GGP-GMR filter, which has a size of less than 2.5 mm, can achieve a spectral detection range of 500-700 nm. Through the direct measurement of the fluorescence emission, the proposed system was demonstrated to detect both the peak wavelength and its corresponding intensity. One fluorescent assay (albumin) and two colorimetric assays (albumin and creatinine) were performed to demonstrate the practical application of the proposed system for quantifying common liquid assays. The results of our system exhibited suitable agreement with those of a commercial spectrometer in terms of the assay sensitivity and limit of detection (LOD). With the proposed system, the fluorescent albumin, colorimetric albumin, and colorimetric creatinine assays achieved LODs of 40.99 and 398 and 25.49 mg/L, respectively. For a wide selection of biomolecules in point-of-care applications, the spectral detection range achieved by the GGP-GMR filter can be further extended and the simple and compact optical path configuration can be integrated with a lab-on-a-chip system.


Asunto(s)
Colorimetría , Dispositivos Laboratorio en un Chip , Límite de Detección , Sistemas de Atención de Punto , Refractometría
4.
Sensors (Basel) ; 21(9)2021 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-33924812

RESUMEN

Digital microfluidics (DMF) devices enable precise manipulation of small liquid volumes in point-of-care testing. A printed circuit board (PCB) substrate is commonly utilized to build DMF devices. However, inkjet printing can be used to fabricate DMF circuits, providing a less expensive alternative to PCB-based DMF designs while enabling more rapid design iteration cycles. We demonstrate the cleanroom-free fabrication process of a low-cost inkjet-printed DMF circuit. We compare Kapton and polymethyl methacrylate (PMMA) as dielectric coatings by measuring the minimal droplet actuation voltage for a range of actuation frequencies. A minimum actuation voltage of 5.6 V was required for droplet movement with the PMMA layer thickness of 0.2 µm and a hydrophobic layer of 0.17 µm. Significant issues with PMMA dielectric breakdown were observed at actuation voltages above 10 V. In comparison, devices that utilized Kapton were found to be more robust, even at an actuation voltage up to 100 V.


Asunto(s)
Dispositivos Laboratorio en un Chip , Microfluídica
5.
Sensors (Basel) ; 21(9)2021 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-33925730

RESUMEN

Nucleic acid (NA) extraction is a basic step for genetic analysis, from scientific research to diagnostic and forensic applications. It aims at preparing samples for its application with biomolecular technologies such as isothermal and non-isothermal amplification, hybridization, electrophoresis, Sanger sequencing and next-generation sequencing. Multiple steps are involved in NA collection from raw samples, including cell separation from the rest of the specimen, cell lysis, NA isolation and release. Typically, this process needs molecular biology facilities, specialized instrumentation and labor-intensive operations. Microfluidic devices have been developed to analyze NA samples with high efficacy and sensitivity. In this context, the integration within the chip of the sample preparation phase is crucial to leverage the promise of portable, fast, user-friendly and economic point-of-care solutions. This review presents an overview of existing lab-on-a-chip (LOC) solutions designed to provide automated NA extraction from human raw biological fluids, such as whole blood, excreta (urine and feces), saliva. It mainly focuses on LOC implementation aspects, aiming to describe a detailed panorama of strategies implemented for different human raw sample preparations.


Asunto(s)
Técnicas Analíticas Microfluídicas , Ácidos Nucleicos , Humanos , Dispositivos Laboratorio en un Chip , Microfluídica , Técnicas de Amplificación de Ácido Nucleico , Sistemas de Atención de Punto
6.
Food Chem ; 354: 129578, 2021 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-33756331

RESUMEN

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.


Asunto(s)
Técnicas Biosensibles/instrumentación , Colorimetría/instrumentación , Dispositivos Laboratorio en un Chip , Poliestirenos/química , Salmonella/aislamiento & purificación , Teléfono Inteligente , Verduras/microbiología , Oro/química , Límite de Detección , Nanopartículas del Metal , Microesferas
7.
Sensors (Basel) ; 21(4)2021 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-33669434

RESUMEN

Microfabrication and Polydimethylsiloxane (PDMS) soft-lithography techniques became popular for microfluidic prototyping at the lab, but even after protocol optimization, fabrication is yet a long, laborious process and partly user-dependent. Furthermore, the time and money required for the master fabrication process, necessary at any design upgrade, is still elevated. Digital Manufacturing (DM) and Rapid-Prototyping (RP) for microfluidics applications arise as a solution to this and other limitations of photo and soft-lithography fabrication techniques. Particularly for this paper, we will focus on the use of subtractive DM techniques for Organ-on-a-Chip (OoC) applications. Main available thermoplastics for microfluidics are suggested as material choices for device fabrication. The aim of this review is to explore DM and RP technologies for fabrication of an OoC with an embedded membrane after the evaluation of the main limitations of PDMS soft-lithography strategy. Different material options are also reviewed, as well as various bonding strategies. Finally, a new functional OoC device is showed, defining protocols for its fabrication in Cyclic Olefin Polymer (COP) using two different RP technologies. Different cells are seeded in both sides of the membrane as a proof of concept to test the optical and fluidic properties of the device.


Asunto(s)
Dispositivos Laboratorio en un Chip , Microfluídica , Microtecnología , Análisis de Secuencia por Matrices de Oligonucleótidos , Polímeros
8.
Sensors (Basel) ; 21(4)2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33671983

RESUMEN

Blood plasma is a source of biomarkers in blood and a simple, fast, and easy extraction method is highly required for point-of-care testing (POCT) applications. This paper proposes a membrane filter integrated microfluidic device to extract blood plasma from whole blood, without any external instrumentation. A commercially available membrane filter was integrated with a newly designed dual-cover microfluidic device to avoid leakage of the extracted plasma and remaining blood cells. Nano-interstices installed on both sides of the microfluidic channels actively draw the extracted plasma from the membrane. The developed device successfully supplied 20 µL of extracted plasma with a high extraction yield (~45%) in 16 min.


Asunto(s)
Dispositivos Laboratorio en un Chip , Técnicas Analíticas Microfluídicas , Microfluídica , Plasma , Pruebas en el Punto de Atención
9.
Sensors (Basel) ; 21(4)2021 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-33671996

RESUMEN

Organ-on-chip devices have provided the pharmaceutical and tissue engineering worlds much hope since they arrived and began to grow in sophistication. However, limitations for their applicability were soon realized as they lacked real-time monitoring and sensing capabilities. The users of these devices relied solely on endpoint analysis for the results of their tests, which created a chasm in the understanding of life between the lab the natural world. However, this gap is being bridged with sensors that are integrated into organ-on-chip devices. This review goes in-depth on different sensing methods, giving examples for various research on mechanical, electrical resistance, and bead-based sensors, and the prospects of each. Furthermore, the review covers works conducted that use specific sensors for oxygen, and various metabolites to characterize cellular behavior and response in real-time. Together, the outline of these works gives a thorough analysis of the design methodology and sophistication of the current sensor integrated organ-on-chips.


Asunto(s)
Dispositivos Laboratorio en un Chip , Impedancia Eléctrica , Análisis de Secuencia por Matrices de Oligonucleótidos
10.
Methods Mol Biol ; 2265: 265-276, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33704721

RESUMEN

Liquid biopsy has emerged as the next generation target for diagnostics and therapeutic monitoring of many diseases including cancer. Liquid biopsy offers noninvasive analysis of aberrant biomolecular changes (e.g., aberrant protein expression, DNA mutation) which can provide crucial information on disease stages and therapy responses. As a diagnostically important biomarker for melanoma, the detection of the BRAFV600E aberration at the DNA and protein level in liquid biopsies confers an attractive option. This method describes the preparation and operation of an integrated multimolecular sensor (IMMS) for simultaneous detection of the BRAFV600E aberration in both molecular forms from circulating melanoma cells in liquid biopsy. IMMS integrates specific melanoma cell capture, cell release, cell lysis, and electrochemical BRAFV600E detection on a single device. IMMS is demonstrated for a sample-to-answer workflow of plasma spiked with melanoma cells.


Asunto(s)
Técnicas Biosensibles/métodos , Inmunoensayo/métodos , Dispositivos Laboratorio en un Chip , Melanoma/metabolismo , Microfluídica/instrumentación , Microfluídica/métodos , Proteínas Proto-Oncogénicas B-raf/metabolismo , Neoplasias Cutáneas/metabolismo , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Técnicas Biosensibles/instrumentación , Técnicas de Cultivo de Célula/métodos , Humanos , Inmunoensayo/instrumentación , Biopsia Líquida/métodos , Melanoma/genética , Melanoma/patología , Mutación , Células Neoplásicas Circulantes/metabolismo , Células Neoplásicas Circulantes/patología , Proteínas Proto-Oncogénicas B-raf/genética , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología
11.
Nat Commun ; 12(1): 1755, 2021 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-33741935

RESUMEN

All-electronic interrogation of biofluid flow velocity by electrical nanosensors incorporated in ultra-low-power or self-sustained systems offers the promise of enabling multifarious emerging research and applications. However, existing nano-based electrical flow sensing technologies remain lacking in precision and stability and are typically only applicable to simple aqueous solutions or liquid/gas dual-phase mixtures, making them unsuitable for monitoring low-flow (~micrometer/second) yet important characteristics of continuous biofluids (such as hemorheological behaviors in microcirculation). Here, we show that monolayer-graphene single microelectrodes harvesting charge from continuous aqueous flow provide an effective flow sensing strategy that delivers key performance metrics orders of magnitude higher than other electrical approaches. In particular, over six-months stability and sub-micrometer/second resolution in real-time quantification of whole-blood flows with multiscale amplitude-temporal characteristics are obtained in a microfluidic chip.


Asunto(s)
Grafito/química , Microelectrodos , Técnicas Analíticas Microfluídicas/instrumentación , Técnicas Analíticas Microfluídicas/métodos , Animales , Velocidad del Flujo Sanguíneo , Bovinos , Cobre/química , Dispositivos Laboratorio en un Chip , Fenómenos Físicos , Polimetil Metacrilato/química
12.
Food Chem ; 351: 129315, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33647686

RESUMEN

Mangiferin-loaded nanobilosomes (MGF-NBSs) were developed using microfluidic-based techniques to improve aqueous solubility, digestive stability, and cellular antioxidant activity (CAA) of mangiferin. Preliminary experiments showed that optimal formation conditions were 5:1 aqueous (water) to solvent (ethanol) phase ratio and 85 mL/min total flow rate. Further optimization using response surface methodology provided the optimal formulation (200 mg encapsulant consisting of 90.91% phosphatidylcholine and 9.09% sodium glycocholate, and 25.89 mg mangiferin), achieving 9.25% mangiferin loading and 80.65% encapsulation efficiency. Mono-dispersed MGF-NBSs with an average size of around 48.14 nm and zeta potential of -30.1 mV were obtained. FTIR and DSC results confirmed the successful encapsulation of mangiferin into the nanobilosomes and revealed interactions among the components. MGF-NBSs showed a 7-fold increase in the aqueous solubility compared with non-encapsulated mangiferin. CAA of MGF-NBSs in Caco-2 cells was 2 times higher than that of mangiferin and the in vitro digestive stability was improved.


Asunto(s)
Antioxidantes/química , Antioxidantes/farmacología , Nanoestructuras/química , Agua/química , Xantonas/química , Xantonas/farmacología , Antioxidantes/metabolismo , Células CACO-2 , Digestión , Composición de Medicamentos , Humanos , Dispositivos Laboratorio en un Chip , Tamaño de la Partícula , Solubilidad , Xantonas/metabolismo
13.
Food Chem ; 351: 129348, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-33647699

RESUMEN

Adulteration of food ingredients, particularly replacement of high-value milk with low-cost milk, affects food safety. For rapid and accurate identification of the possible adulterating milk species in an unknown sample, a centrifugal microfluidic chip-based real-time fluorescent multiplex loop-mediated isothermal amplification (LAMP) assay was developed to simultaneously detect milk from cow, camel, horse, goat, and yak. Using precoated primers in different reaction wells, the centrifugal microfluidic chip markedly simplified the detection process and reduced false-positive results. The entire amplification was completed within 90 min with a genomic detection limit of 0.05 ng/µL in cow, camel, horse, and goat milk and 0.005 ng/µL in yak milk. Using simulated adulterated samples for validation, the detection limit for adulterated milk samples was 2.5%, satisfying authentication requirements, as the proportion of adulterated milk higher than 10% affects economic interests. Therefore, this simple, centrifugal, microfluidic chip-based multiplex real-time fluorescent LAMP assay can simultaneously detect common milk species in commercial products to enable accurate labeling.


Asunto(s)
Centrifugación/instrumentación , Calidad de los Alimentos , Dispositivos Laboratorio en un Chip , Leche/química , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Amplificación de Ácido Nucleico/instrumentación , Animales , Bovinos , Cartilla de ADN/genética , Femenino , Leche/normas , Factores de Tiempo
14.
Nat Protoc ; 16(4): 2023-2050, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33674788

RESUMEN

Advanced in vitro kidney models are of great importance to the study of renal physiology and disease. Kidney tubuloids can be established from primary cells derived from adult kidney tissue or urine. Tubuloids are three-dimensional multicellular structures that recapitulate tubular function and have been used to study infectious, malignant, metabolic, and genetic diseases. For tubuloids to more closely represent the in vivo kidney, they can be integrated into an organ-on-a-chip system that has a more physiological tubular architecture and allows flow and interaction with vasculature or epithelial and mesenchymal cells from other organs. Here, we describe a detailed protocol for establishing tubuloid cultures from tissue and urine (1-3 weeks), as well as for generating and characterizing tubuloid cell-derived three-dimensional tubular structures in a perfused microfluidic multi-chip platform (7 d). The combination of the two systems yields a powerful in vitro tool that better recapitulates the complexity of the kidney tubule with donor-specific properties.


Asunto(s)
Túbulos Renales/crecimiento & desarrollo , Dispositivos Laboratorio en un Chip , Organoides/crecimiento & desarrollo , Perfusión , Técnicas de Cultivo de Tejidos/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Animales , Fraccionamiento Celular , Niño , Preescolar , Impedancia Eléctrica , Femenino , Colorantes Fluorescentes/química , Humanos , Lactante , Masculino , Proteínas de Transporte de Membrana/metabolismo , Microfluídica , Persona de Mediana Edad , Ratas , Adulto Joven
16.
Clin Chem ; 67(4): 672-683, 2021 03 31.
Artículo en Inglés | MEDLINE | ID: mdl-33788940

RESUMEN

BACKGROUND: Infectious disease outbreaks such as the COVID-19 (coronavirus disease 2019) pandemic call for rapid response and complete screening of the suspected community population to identify potential carriers of pathogens. Central laboratories rely on time-consuming sample collection methods that are rarely available in resource-limited settings. METHODS: We present a highly automated and fully integrated mobile laboratory for fast deployment in response to infectious disease outbreaks. The mobile laboratory was equipped with a 6-axis robot arm for automated oropharyngeal swab specimen collection; virus in the collected specimen was inactivated rapidly using an infrared heating module. Nucleic acid extraction and nested isothermal amplification were performed by a "sample in, answer out" laboratory-on-a-chip system, and the result was automatically reported by the onboard information platform. Each module was evaluated using pseudovirus or clinical samples. RESULTS: The mobile laboratory was stand-alone and self-sustaining and capable of on-site specimen collection, inactivation, analysis, and reporting. The automated sampling robot arm achieved sampling efficiency comparable to manual collection. The collected samples were inactivated in as short as 12 min with efficiency comparable to a water bath without damage to nucleic acid integrity. The limit of detection of the integrated microfluidic nucleic acid analyzer reached 150 copies/mL within 45 min. Clinical evaluation of the onboard microfluidic nucleic acid analyzer demonstrated good consistency with reverse transcription quantitative PCR with a κ coefficient of 0.979. CONCLUSIONS: The mobile laboratory provides a promising solution for fast deployment of medical diagnostic resources at critical junctions of infectious disease outbreaks and facilitates local containment of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) transmission.


Asunto(s)
/métodos , Laboratorios , Unidades Móviles de Salud , Patología Molecular/métodos , ARN Viral/análisis , Adulto , Automóviles , /instrumentación , Femenino , Humanos , Dispositivos Laboratorio en un Chip , Masculino , Técnicas Analíticas Microfluídicas/instrumentación , Técnicas Analíticas Microfluídicas/métodos , Coronavirus del Síndrome Respiratorio de Oriente Medio/química , Técnicas de Diagnóstico Molecular/instrumentación , Técnicas de Diagnóstico Molecular/métodos , Pandemias , Patología Molecular/instrumentación , Robótica , /química
17.
Appl Opt ; 60(7): 1924-1929, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33690282

RESUMEN

A rapid and label free aflatoxin B1 (AFB1) microfluid sensor was proposed and tested. The device was fabricated with hollow-core photonics crystal fiber infiltrated with the AFB1 solution. The autofluorescence emitting from the AFB1 molecules was detected. The sensor length was optimized. The AFB1 concentration was tested with a 4 cm long sensor. The best limit of detection was achieved as low as 1.34 ng/ml, which meets the test requirement of the national standards for AFB1 in food. The effectiveness of this sensor being applied in beer solution was also verified to be a little more sensitive than in aqueous solution. Compared with traditional AFB1 detection methods, the proposed single-ended device perfectly satisfies the demand of process control in alcoholic beverages manufacture.


Asunto(s)
Aflatoxina B1/química , Bebidas Alcohólicas/análisis , Contaminación de Alimentos/análisis , Dispositivos Laboratorio en un Chip , Bebidas Alcohólicas/microbiología , Microbiología de Alimentos , Límite de Detección
18.
Sci Adv ; 7(12)2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33731349

RESUMEN

Despite the importance of nucleic acid testing in managing the COVID-19 pandemic, current detection approaches remain limited due to their high complexity and extensive processing. Here, we describe a molecular nanotechnology that enables direct and sensitive detection of viral RNA targets in native clinical samples. The technology, termed catalytic amplification by transition-state molecular switch (CATCH), leverages DNA-enzyme hybrid complexes to form a molecular switch. By ratiometric tuning of its constituents, the multicomponent molecular switch is prepared in a hyperresponsive state-the transition state-that can be readily activated upon the binding of sparse RNA targets to turn on substantial enzymatic activity. CATCH thus achieves superior performance (~8 RNA copies/µl), direct fluorescence detection that bypasses all steps of PCR (<1 hour at room temperature), and versatile implementation (high-throughput 96-well format and portable microfluidic assay). When applied for clinical COVID-19 diagnostics, CATCH demonstrated direct and accurate detection in minimally processed patient swab samples.


Asunto(s)
Dispositivos Laboratorio en un Chip , Técnicas Analíticas Microfluídicas , Pruebas en el Punto de Atención , /genética , /diagnóstico , /instrumentación , Humanos , Límite de Detección
19.
Anal Chem ; 93(9): 4270-4276, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33635067

RESUMEN

Airborne pathogens have been considered as highly infectious and transmittable between humans. With the pandemic outbreak of the coronavirus disease 2019 (COVID-19), an on-site diagnostic system-integrated airborne pathogen-monitoring machine is recommended by experts for preventing and controlling the early stage ß-coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread. In this work, a small-volume rotating microfluidic fluorescence chip-integrated aerosol SARS-CoV-2 sampling system was constructed to satisfy the demand for rapid on-site sample collection and detection of SARS-CoV-2. The rotating microfluidic fluorescence system with small volume has very high sensitivity in the detection of SARS-CoV-2 (detection limit of 10 copies/µL with the shortest Ct value of 15 min), which is comparable to reverse transcription polymerase chain reaction (RT-PCR). The precision variation coefficients within/between batches are very low [coefficient of variation (CV) % ≤ 5.0%]. Our work has passed the comprehensive inspection of the microfluidic chip performance by the Shanghai Medical Device Testing Institute [National Medical Inspection (Design) no. 4408] and successfully tested 115 clinical samples. The integrated system exhibits 100% specificity, high sensitivity (10 copies/µL), and good precision (CV % ≤ 5.0%) in the rapid detection of SARS-CoV-2, thus realizing rapid monitoring and diagnostics of SARS-CoV-2 nucleic acid on-site.


Asunto(s)
/instrumentación , /diagnóstico , Dispositivos Laboratorio en un Chip , /aislamiento & purificación , Aerosoles/análisis , Aire , Fluorescencia , Humanos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sensibilidad y Especificidad
20.
Environ Sci Technol ; 55(5): 3001-3008, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33566594

RESUMEN

The aim of this study is to demonstrate how the flow and diffusion of nanoplastics through a salinity gradient (SG), as observed in mangrove swamps (MSPs), influence their aggregation pathways. These two parameters have never yet been used to evaluate the fate and behavior of colloids in the environment, since they cannot be incorporated into classical experimental setups. Land-sea continuums, such as estuaries and MSP systems, are known to be environmentally reactive interfaces that influence the colloidal distribution of pollutants. Using a microfluidic approach to reproduce the SG and its dynamics, the results show that nanoplastics arriving in a MSP are fractionated. First, a substantial fraction rapidly aggregates to reach the microscale, principally governed by an orthokinetic aggregation process and diffusiophoresis drift. These large nanoplastic aggregates eventually float near the water's surface or settle into the sediment at the bottom of the MSP, depending on their density. The second, smaller fraction remains stable and is transported toward the saline environment. This distribution results from the combined action of the spatial salt concentration gradient and orthokinetic aggregation, which is largely underestimated in the literature. Due to nanoplastics' reactive behavior, the present work demonstrates that mangrove and estuarine systems need to be better examined regarding plastic pollution.


Asunto(s)
Plásticos , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Estuarios , Dispositivos Laboratorio en un Chip , Microplásticos , Salinidad , Contaminantes Químicos del Agua/análisis
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