15 results on '"Shunji Li"'
Search Results
2. Rapid Assembly of Cellulose Microfibers into Translucent and Flexible Microfluidic Paper-Based Analytical Devices via Wettability Patterning
- Author
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Peng Ma, Shanshan Wang, Jie Wang, Yu Wang, Yue Dong, Shunji Li, Huiying Su, Peng Chen, Xiaojun Feng, Yiwei Li, Wei Du, and Bi-Feng Liu
- Subjects
Paper ,Glucose ,Lab-On-A-Chip Devices ,Microfluidics ,Wettability ,Humans ,Microfluidic Analytical Techniques ,Cellulose ,Analytical Chemistry - Abstract
Microfluidic paper-based analytical devices (μPADs) are emerging as powerful analytical platforms in clinical diagnostics, food safety, and environmental protection because of their low cost and favorable substrate properties for biosensing. However, the existing top-down fabrication methods of paper-based chips suffer from low resolution (200 μm). Additionally, papers have limitations in their physical properties (e.g., thickness, transmittance, and mechanical flexibility). Here, we demonstrate a bottom-up approach for the rapid fabrication of heterogeneously controlled paper-based chip arrays. We simply print a wax-patterned microchip with wettability contrasts, enabling automatic and selective assembly of cellulose microfibers to construct predefined paper-based microchip arrays with controllable thickness. This paper-based microchip printing technology is feasible for various substrate materials ranging from inorganic glass to organic polymers, providing a versatile platform for the full range of applications including transparent devices and flexible health monitoring. Our bottom-up printing technology using cellulose microfibers as the starting material provides a lateral resolution down to 42 ± 3 μm and achieves the narrowest channel barrier down to 33 ± 2 μm. As a proof-of-concept demonstration, a flexible paper-based glucose monitor is built for human health care, requiring only 0.3 μL of sample for testing.
- Published
- 2022
3. A time-coded multi-concentration microfluidic chemical waveform generator for high-throughput probing suspension single-cell signaling
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Peng Chen, Xiaojun Feng, Yiran Guo, Yiwei Li, Bi-Feng Liu, Zhaolong Gao, and Shunji Li
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Cell signaling ,Microchannel ,Signal generator ,Materials science ,Pulse (signal processing) ,Microfluidics ,Waveform ,General Chemistry ,Biological system ,Multiplexing ,Throughput (business) - Abstract
The cellular response to the complex extracellular microenvironment is highly dynamic in time and type of extracellular matrix. Accurately reconstructing this process and analyzing the changes in receptor conformation on the cell membrane surface and intracellular or intercellular signaling has been a major challenge in analytical chemistry and biophysical methodology. In this paper, a time-coded multi-concentration microfluidic chemical waveform generator was developed for the dynamic signaling probing with single-cell array of high temporal resolution, high throughput, and multi-concentration combination stimulation. Based on innovative microchannel structure, sophisticated external control methods and multiplexing technology, the system not only allowed for temporally sequential permutations of the four concentrations of stimuli (time code), but also generated pulsed and continuous waveforms at different frequencies in a highly controllable manner. Furthermore, the single-cell trap array was set up to efficiently capture cells in suspension, dramatically increasing throughput and reducing experiment preparation time. The maximum frequency of the platform was 1 Hz, and one cell could be stimulated at multiple frequencies. To show the ability of the system to investigate rapid biochemical events in high throughput, pulse stimulation and continuous stimulation of different frequencies and different time codes, combined with four concentrations of histamine (HA), were generated for probing G protein-coupled receptor (GPCR) signaling in HeLa cells. Then, statistical analysis was performed for the mean peak height and mean peak area of the cellular response. We believe that the time-coded multi-concentration microfluidic chemical waveform generator will provide a novel strategy for analytical chemistry, biophysics, cell signaling, and individualized medicine applications.
- Published
- 2022
4. Hand-powered centrifugal micropipette-tip with distance-based quantification for on-site testing of SARS-CoV-2 virus
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Chungen Qian, Jiashuo Li, Zheng Pang, Han Xie, Chao Wan, Shunji Li, Xin Wang, Yujin Xiao, Xiaojun Feng, Yiwei Li, Peng Chen, and Bi-Feng Liu
- Subjects
Analytical Chemistry - Published
- 2023
5. Defining the HIV Capsid Binding Site of Nucleoporin 153
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Shunji Li, Jagdish Suresh Patel, Jordan Yang, Angela Marie Crabtree, Brenda Marilyn Rubenstein, Peik Karl Lund-Andersen, Frederick Marty Ytreberg, and Paul Andrew Rowley
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Nuclear Pore Complex Proteins ,Capsid ,Binding Sites ,Phenylalanine ,HIV-1 ,Glycine ,Animals ,Humans ,HIV Infections ,Capsid Proteins ,Amino Acids ,Molecular Biology ,Microbiology - Abstract
The interaction between the HIV-1 capsid and human nucleoporin 153 (NUP153) is vital for delivering the HIV-1 preintegration complex into the nucleus via the nuclear pore complex. The interaction with the capsid requires a phenylalanine/glycine-containing motif in the C-terminus of NUP153 (NUP153C). This study used molecular modeling and biochemical assays to comprehensively determine the amino acids in NUP153 that are important for capsid interaction. Molecular dynamics, FoldX, and PyRosetta simulations delineated the minimal capsid binding motif of NUP153 based on the known structure of NUP153 bound to the HIV-1 capsid hexamer. Computational predictions were experimentally validated by testing the interaction of NUP153 with capsid using aniin vitro/ibinding assay and a cell-based TRIM-NUP153C restriction assay. This work identified eight amino acids from P1411 to G1418 that stably engage with capsid, with significant correlations between the interactions predicted by molecular models and empirical experiments. This validated the usefulness of this multidisciplinary approach to rapidly characterize the interaction between human proteins and the HIV-1 capsid.bIMPORTANCE/bThe human immunodeficiency virus (HIV) can infect nondividing cells by interacting with the host nuclear pore complex. The host nuclear pore protein NUP153 directly interacts with the HIV capsid to promote viral nuclear entry. This study used a multidisciplinary approach combining computational and experimental techniques to comprehensively map the effect of mutating the amino acids of NUP153 on HIV capsid interaction. This work showed a significant correlation between computational and empirical data sets, revealing that the HIV capsid interacted specifically with only six amino acids of NUP153. The simplicity of the interaction motif suggested other FG-containing motifs could also interact with the HIV-1 capsid. Furthermore, it was predicted that naturally occurring polymorphisms in human and nonhuman primates would disrupt NUP153 interaction with capsid, potentially protecting certain populations from HIV-1 infection.
- Published
- 2022
6. Multi-reagents dispensing centrifugal microfluidics for point-of-care testing
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Yujin Xiao, Shunji Li, Zheng Pang, Chao Wan, Lina Li, Huijuan Yuan, Xianzhe Hong, Wei Du, Xiaojun Feng, Yiwei Li, Peng Chen, and Bi-Feng Liu
- Subjects
Point-of-Care Testing ,Microfluidics ,Electrochemistry ,Biomedical Engineering ,Biophysics ,Escherichia coli ,Indicators and Reagents ,General Medicine ,Biosensing Techniques ,Nucleic Acid Amplification Techniques ,Biotechnology - Abstract
Point-of-care testing (POCT) has shown great advantages for public health monitoring in resource-limited settings. However, developing of POCT tools with automated and accurate quantitative dispensing of multiple reagents and samples is challenging. Here, we demonstrate a novel multi-reagents dispensing centrifugal microfluidics (MDCM) that allows rapid and automated dispensing of multiple reagents and samples with high throughput and accuracy. The MDCM was designed with multiple aliquoting units with the hydrophobic valve at different radial positions. All reagents and samples were loaded simultaneously, dispensed in parallel by centrifugation at low speed, and then introduced into the reaction chamber sequentially by centrifugation at high speed. Two MDCM chips are demonstrated, including a uniform concentration generator and a gradient concentration generator. The concentration coefficient of variation (CV) among the independent reaction chambers was lower than 0.56%, and the theoretical quantitative concentration gradient was strongly correlated with the actual concentration gradient (R
- Published
- 2022
7. Multi-Reagents Dispensing Centrifugal Microfluidics for Point-of-Care Testing
- Author
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Yujin Xiao, Shunji Li, Zheng Pang, Chao Wan, Lina Li, Huijuan Yuan, Xianzhe Hong, Wei Du, Xiaojun Feng, Peng Chen, and Bifeng Liu
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
8. Multichannel Synchronous Hydrodynamic Gating Coupling with Concentration Gradient Generator for High-Throughput Probing Dynamic Signaling of Single Cells
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Yiran Guo, Bi-Feng Liu, Jinchi Zhu, Peng Chen, Zhaolong Gao, Yinan Liu, and Shunji Li
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education.field_of_study ,Cell signaling ,Chemistry ,010401 analytical chemistry ,Microfluidics ,Population ,Gating ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Coupling (electronics) ,Amplitude ,Hydrodynamics ,Humans ,Single-Cell Analysis ,Signal transduction ,education ,Biological system ,Throughput (business) ,Signal Transduction - Abstract
Cell signaling greatly affected by complicated and temporally dynamic extracellular microenvironments controls most of the physiological functions in vivo. To reconstruct or simulate such microenvironments in vitro represents a fundamental approach for revealing the underlying mechanisms of those sophisticated processes. Recent advances in microfluidics have added a new dimension to cell signaling analysis, for example, concentration gradient generators (amplitude aspect) or hydrodynamic gating strategy (frequency aspect), but it is still challengeable to capture single-cell dynamic signaling in response to a mimicked extracellular microenvironment with varied stimuli waveforms of different amplitude and frequency in a high-throughput manner. In this article, we proposed a novel microfluidic strategy coupling multichannel synchronous hydrodynamic gating with microfluidic concentration gradient generators (μMHG-CGG) to probe dynamic signaling of single cells with high throughput. The μMHG-CGG allows rapid delivery of dynamic chemical signals in both high frequency (as high as 670 mHz) and multiple amplitude domains at the same time and simultaneously high-throughput probing cell dynamics at single-cell resolution in real time. By applying the proposed system, the mechanisms for encoding/decoding systems (termed "frequency coding" or "amplitude coding") via GPCRs-mediated signaling pathways responding to histamine (HA) and adenosine triphosphate (ATP) in single HeLa cells were investigated. The optimal drug concentrations of single cells responses to HA and ATP individually or in combination were also successfully discussed, allowing us to obtain both single-cell heterogeneity and statistics from the cell population.
- Published
- 2020
9. Rapid Determination of Phase Diagrams for Biomolecular Liquid-Liquid Phase Separation with Microfluidics
- Author
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Pengjie Li, Xuemei Zeng, Shunji Li, Xufu Xiang, Peng Chen, Yiwei Li, and Bi-Feng Liu
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Microfluidics ,Printing, Three-Dimensional ,Proteins ,Analytical Chemistry - Abstract
Biomolecular phase separation is currently emerging in both the medical and life science fields. Meanwhile, the application of liquid-liquid phase separation has been extended to many fields including drug discovery, fibrous material fabrication, 3D printing, and polymer design. Although more than 8600 proteins and other synthetic macromolecules are capable of phase separation as recently reported, there is still a lack of a high-throughput approach to quantitatively characterize its phase behaviors. To meet this requirement, here, we proposed fast and high-resolution acquisition of biomolecular phase diagrams using microfluidic chips. Using this platform, we demonstrated the phase behavior of polyU/RRASLRRASLRRASL in a quantitative manner. Up to 1750 concentration conditions can be generated in 140 min. The detection limitation of our device to capture the saturation concentration for phase separation is about 5 times lower than that of the traditional turbidity method. Thus, our results provide a basis for the rapid acquisition of phase diagrams with high-throughput and pave the way for its wide application.
- Published
- 2021
10. Microfluidic chip electrophoresis for biochemical analysis
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Peng Chen, Xizhi Huang, Xiaowen Ou, Bi-Feng Liu, and Shunji Li
- Subjects
Ions ,Gel electrophoresis ,Chromatography ,Chemistry ,010401 analytical chemistry ,Microfluidics ,Electrophoresis, Capillary ,Proteins ,Filtration and Separation ,Electrochemical Techniques ,02 engineering and technology ,Microfluidic Analytical Techniques ,Dielectrophoresis ,021001 nanoscience & nanotechnology ,Mass spectrometry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Electrophoresis ,Capillary electrophoresis ,Microfluidic chip ,Nucleic Acids ,Amino Acids ,0210 nano-technology - Abstract
Microfluidic chip electrophoresis has been widely employed for separation of various biochemical species owing to its advantages of low sample consumption, low cost, fast analysis, high throughput, and integration capability. In this article, we reviewed the development of four different modes of microfluidics-based electrophoresis technologies including capillary electrophoresis, gel electrophoresis, dielectrophoresis, and field (electric) flow fractionation. Coupling detection schemes on microfluidic electrophoresis platform were also reviewed such as optical, electrochemical, and mass spectrometry method. We further discussed the innovative applications of microfluidic electrophoresis for biomacromolecules (nucleic acids and proteins), biochemical small molecules (amino acids, metabolites, ions, etc.), and bioparticles (cells and pathogens) analysis. The future direction of microfluidic chip electrophoresis was predicted.
- Published
- 2019
11. Microfluidics towards single cell resolution protein analysis
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Shunji Li, Dongjuan Chen, Bi-Feng Liu, Peng Chen, and Xiaowen Ou
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Gel electrophoresis ,Materials science ,Resolution (mass spectrometry) ,010401 analytical chemistry ,Microfluidics ,Nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Electrophoresis ,Capillary electrophoresis ,Single-cell analysis ,Image Cytometry ,Cytometry ,Spectroscopy - Abstract
Single cell analysis has aroused great interest with its remarkable ability to investigate cell-to-cell heterogeneity in large populations. However, probing protein information at single cells resolution including quantity, interactions, and dynamics have been great challenges as a result of the small size of cells, the complexity and a large concentration range of the protein and the lack of genome-wide amplification method. Fortunately, microfluidics capable of high throughput, high reproducibility, large parallelization, easy operability and low-cost, has been emerging as a powerful platform for the analysis of single cell proteins. In this review, we focus the recent advances of microfluidics in single cell resolution protein analysis, particularly covering the following aspects: (1) microfluidic electrophoresis (capillary electrophoresis and gel electrophoresis); (2) microfluidic cytometry (microfluidic flow cytometry, droplet based cytometry and image cytometry); (3) microfluidic array (micro wells, micro chambers, valve-based microfluidics and static droplet array microfluidics); (4) microfluidic probe and (5) microfluidics based mass spectrometry.
- Published
- 2019
12. A review on microfluidics manipulation of the extracellular chemical microenvironment and its emerging application to cell analysis
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Peng Chen, Xuemei Zeng, Bi-Feng Liu, Yiran Guo, and Shunji Li
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Convection flow ,Chemistry ,Microfluidics ,Drug Evaluation, Preclinical ,High resolution ,Cell analysis ,Nanotechnology ,Cell Differentiation ,Cell Communication ,Microfluidic Analytical Techniques ,Biochemistry ,Analytical Chemistry ,Multicellular organism ,Cellular Microenvironment ,Cell Movement ,Cell Line, Tumor ,Lab-On-A-Chip Devices ,Flow switching ,Extracellular ,Environmental Chemistry ,Surface chemical ,Animals ,Humans ,Spectroscopy - Abstract
Spatiotemporal manipulation of extracellular chemical environments with simultaneous monitoring of cellular responses plays an essential role in exploring fundamental biological processes and expands our understanding of underlying mechanisms. Despite the rapid progress and promising successes in manipulation strategies, many challenges remain due to the small size of cells and the rapid diffusion of chemical molecules. Fortunately, emerging microfluidic technology has become a powerful approach for precisely controlling the extracellular chemical microenvironment, which benefits from its integration capacity, automation, and high-throughput capability, as well as its high resolution down to submicron. Here, we summarize recent advances in microfluidics manipulation of the extracellular chemical microenvironment, including the following aspects: i) Spatial manipulation of chemical microenvironments realized by convection flow-, diffusion-, and droplet-based microfluidics, and surface chemical modification; ii) Temporal manipulation of chemical microenvironments enabled by flow switching/shifting, moving/flowing cells across laminar flows, integrated microvalves/pumps, and droplet manipulation; iii) Spatiotemporal manipulation of chemical microenvironments implemented by a coupling strategy and open-space microfluidics; and iv) High-throughput manipulation of chemical microenvironments. Finally, we briefly present typical applications of the above-mentioned technical advances in cell-based analyses including cell migration, cell signaling, cell differentiation, multicellular analysis, and drug screening. We further discuss the future improvement of microfluidics manipulation of extracellular chemical microenvironments to fulfill the needs of biological and biomedical research and applications.
- Published
- 2020
13. Novel Double-Stranded RNA Viruses Discovered within Saccharomyces cerevisiae
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Angela Crabtree, Nathan Taggart, Camden Doering, Shunji Li, Lance Fredericks, Josephine Boyer, James van Leuven, and Paul Rowley
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General Materials Science - Abstract
Saccharomyces yeasts harbor many different viruses and parasitic genetic elements, including double-stranded RNA (dsRNA) viruses from the family Totiviridae. The identification of novel dsRNA viruses in yeasts has been constrained by the lack of effective protocols for the unbiased preparation and sequencing of dsRNAs. We have developed a next-generation sequencing method that enables the amplification and sequencing of yeast dsRNAs. Using this method, we have performed a metagenomic screen of more than 600 strains of Saccharomyces cerevisiae for the presence of novel dsRNA viruses. Surprisingly, we have identified several novel bipartite dsRNA viruses from the family Partitiviridae within different strains of S. cerevisiae. Partitiviruses have never been described within Saccharomyces yeasts or within the wider Saccharomycotina taxonomic subdivision of the Ascomycota phylum. We confirmed the presence of these partitivirus dsRNAs using reverse transcriptase-PCR and have been successful in purifying viral particles from infected yeasts. After deep sequencing of purified dsRNAs, we have identified three species of virus that have weak homology (20-35% amino acid identity) to viruses of the genus Cryspovirus, which replicate within the protozoan pathogen Cryptosporidium parvum. Partitiviruses can modulate the virulence and fecundity of plant and human pathogens, respectively. The discovery of partitiviruses in S. cerevisiae will enable the study of how partitiviruses interact with the host cell environment and alter cellular physiology.
- Published
- 2019
14. Rapid exosomes concentration and in situ detection of exosomal microRNA on agarose-based microfluidic chip
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Peng Chen, Xiaojun Feng, Bi-Feng Liu, Chungen Qian, Jie Wang, Bo Wei, Shunji Li, Wei Du, Yiwei Li, and Yujin Xiao
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In situ ,Detection limit ,Chemistry ,Metals and Alloys ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Exosome ,Microvesicles ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Cell biology ,chemistry.chemical_compound ,Microfluidic chip ,microRNA ,Materials Chemistry ,Agarose ,Electrical and Electronic Engineering ,Liquid biopsy ,0210 nano-technology ,Instrumentation - Abstract
Exosomes, together with their accompanying proteins and nucleic acids have been increasingly recognized as biomarkers for non-invasive tumor diagnostic and prognostic. However, rapid and efficient detection of exosomes remains challenging, due to their small size (30−150 nm), and low concentration. Thus, to guarantee, especially when cancer screening requires detection limits lower than exosome concentrations, it not only needs to isolate and purify exosomes, but it needs to preconcentrate them as well. Here, a low-cost, rapid, and portable agarose-based microfluidic chip for exosome concentration and in situ exosomal microRNA detection was developed, termed isExoCD (in situ exosome concentration and detection). The target exosomes loaded at the entrance will be automatically enriched at the closed end of the microchannel by leveraging the capillary effect and the strong water permeability of the agarose gel. To detect the exosomal microRNA, we integrated the catalyzed hairpin assembly (CHA) based strategy into the isExoCD, allowing high sensitive detection of exosomes with a limit of detection (LOD) of ∼103. Using our method, we can successfully distinguish cancer cell-derived exosomes from other exosomes that obtained other cell types. Thus, our platform paves a new avenue to early cancer detection, liquid biopsy, and point-of-care diagnosis.
- Published
- 2021
15. Integrated and finger-actuated microfluidic chip for point-of-care testing of multiple pathogens
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Peng Chen, Huiying Su, Chen Chen, Mengfan Zhou, Wei Du, Xiaojun Feng, Bi-Feng Liu, and Shunji Li
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Fluorescence-lifetime imaging microscopy ,business.industry ,Chemistry ,Point-of-Care Systems ,Microfluidics ,010401 analytical chemistry ,Loop-mediated isothermal amplification ,Pipette ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Chip ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Template ,Molecular Diagnostic Techniques ,Point-of-Care Testing ,Optoelectronics ,Sample preparation ,0210 nano-technology ,business ,Nucleic Acid Amplification Techniques ,Layer (electronics) - Abstract
The integration of gel-based loop-mediated isothermal amplification (gLAMP) and finger-actuated microfluidic chip (μFAchip) was developed for the simultaneous detection of various different types of bacterial pathogens. The developed μFAchip consisted of three PDMS layers attached together by two adhesive tapes. Multiple chambers in the top PDMS layer were used for sample preparation, and the corresponding chambers in the bottom PDMS layer was used for long-term storage of LAMP reagents without DNA templates. The thin PDMS layer in the middle contained cross-shaped cuts as finger-actuated valves for fluid control. To reduce operation steps on the chip, such as pipetting and manipulation of samples, Whatman CloneSaver card was pre-embedded in the top chambers for on-chip DNA extraction and purification. Upon a simple press on the top layer, the finger-actuated valve was opened up, allowing DNA samples on the top layer flow into the bottom reaction chambers for gLAMP reaction. For POCT applications, on-chip LAMP reaction and imaging were conducted on a miniaturized peltier heater and a portable fluorescence imaging system respectively. Under the optimized condition, multiple pathogens were detected simultaneously with high selectivity and sensitivity (as low as 1.6 cells). The developed μFAchip provided a rapid and easy-to-operate platform for gLAMP-based pathogen detection, with the potential for in-field detection, especially in areas with limited resources.
- Published
- 2021
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