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Milanese T, Bruschini C, Burri S, Bernasconi E, Ulku AC, Charbon E. LinoSPAD2: an FPGA-based, hardware-reconfigurable 512×1 single-photon camera system. OPTICS EXPRESS 2023; 31:44295-44314. [PMID: 38178504 DOI: 10.1364/oe.505748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/26/2023] [Indexed: 01/06/2024]
Abstract
We report on LinoSPAD2, a single-photon camera system, comprising a 512×1 single-photon avalanche diode (SPAD) front-end and one or two FPGA-based back-ends. Digital signals generated by the SPADs are processed by the FPGA in real time, whereas the FPGA offers full reconfigurability at a very high level of granularity both in time and space domains. The LinoSPAD2 camera system can process 512 SPADs simultaneously through 256 channels, duplicated on each FPGA-based back-end, with a bank of 64 time-to-digital converters (TDCs) operating at 133 MSa/s, whereas each TDC has a time resolution of 20 ps (LSB). To the best of our knowledge, LinoSPAD2 is the first fully reconfigurable SPAD camera system of large format. The SPAD front-end features a pitch of 26.2 μm, a native fill factor of 25.1%, and a microlens array achieving 2.3× concentration factor. At room temperature, the median dark count rate (DCR) is 80 cps at 7 V excess bias, the peak photon detection probability (PDP) is 53% at 520 nm wavelength, and the single-photon timing resolution (SPTR) is 50 ps FWHM. The instrument response function (IRF) is around 100 ps FWHM at system level. The LinoSPAD2 camera system is suitable for numerous applications, including LiDAR imaging, heralded spectroscopy, compressive Raman sensing, and other computational imaging techniques.
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2
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He Y, Qiao Y, Ding L, Cheng T, Tu J. Recent advances in droplet sequential monitoring methods for droplet sorting. BIOMICROFLUIDICS 2023; 17:061501. [PMID: 37969470 PMCID: PMC10645479 DOI: 10.1063/5.0173340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/23/2023] [Indexed: 11/17/2023]
Abstract
Droplet microfluidics is an attractive technology to run parallel experiments with high throughput and scalability while maintaining the heterogeneous features of individual samples or reactions. Droplet sorting is utilized to collect the desired droplets based on droplet characterization and in-droplet content evaluation. A proper monitoring method is critical in this process, which governs the accuracy and maximum frequency of droplet handling. Until now, numerous monitoring methods have been integrated in the microfluidic devices for identifying droplets, such as optical spectroscopy, mass spectroscopy, electrochemical monitoring, and nuclear magnetic resonance spectroscopy. In this review, we summarize the features of various monitoring methods integrated into droplet sorting workflow and discuss their suitable condition and potential obstacles in use. We aim to provide a systematic introduction and an application guide for choosing and building a droplet monitoring platform.
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Affiliation(s)
- Yukun He
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Yi Qiao
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Lu Ding
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Tianguang Cheng
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Jing Tu
- State Key Laboratory of Digital Medical Engineering, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
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3
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Morales-Moreno MD, Valdés-Galindo EG, Reza MM, Fiordelisio T, Peon J, Hernandez-Garcia A. Multiplex gRNAs Synergically Enhance Detection of SARS-CoV-2 by CRISPR-Cas12a. CRISPR J 2023; 6:116-126. [PMID: 36944123 DOI: 10.1089/crispr.2022.0074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) diagnostic methods have a large potential to effectively detect SARS-CoV-2 with sensitivity and specificity nearing 100%, comparable to quantitative polymerase chain reaction. Yet, there is room for improvement. Commonly, one guide CRISPR RNA (gRNA) is used to detect the virus DNA and activate Cas collateral activity, which cleaves a reporter probe. In this study, we demonstrated that using 2-3 gRNAs in parallel can create a synergistic effect, resulting in a 4.5 × faster cleaving rate of the probe and increased sensitivity compared to using individual gRNAs. The synergy is due to the simultaneous activation of CRISPR-Cas12a and the improved performance of each gRNA. This approach was able to detect as few as 10 viral copies of the N-gene of SARS-CoV-2 RNA after a preamplification step using reverse transcription loop-mediated isothermal amplification. The method was able to accurately detect 100% of positive and negative clinical samples in ∼25 min using a fluorescence plate reader and ∼45 min with lateral flow strips.
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Affiliation(s)
- Melissa D Morales-Moreno
- Laboratory of Biomolecular Engineering and Bionanotechnology, Department of Chemistry of Biomacromolecules, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Erick G Valdés-Galindo
- Laboratory of Biomolecular Engineering and Bionanotechnology, Department of Chemistry of Biomacromolecules, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Mariana M Reza
- Department of Physical Chemistry, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Tatiana Fiordelisio
- Laboratorio de Neuroendocrinología Comparada, Laboratorio Nacional de Soluciones Biomiméticas para Diagnóstico y Terapia LaNSBioDyT, Faculty of Sciences, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Jorge Peon
- Department of Physical Chemistry, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
| | - Armando Hernandez-Garcia
- Laboratory of Biomolecular Engineering and Bionanotechnology, Department of Chemistry of Biomacromolecules, Institute of Chemistry, National Autonomous University of Mexico, Ciudad Universitaria, Ciudad de Mexico, Mexico
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Huang C, Jiang Y, Li Y, Zhang H. Droplet Detection and Sorting System in Microfluidics: A Review. MICROMACHINES 2022; 14:mi14010103. [PMID: 36677164 PMCID: PMC9867185 DOI: 10.3390/mi14010103] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 05/26/2023]
Abstract
Since being invented, droplet microfluidic technologies have been proven to be perfect tools for high-throughput chemical and biological functional screening applications, and they have been heavily studied and improved through the past two decades. Each droplet can be used as one single bioreactor to compartmentalize a big material or biological population, so millions of droplets can be individually screened based on demand, while the sorting function could extract the droplets of interest to a separate pool from the main droplet library. In this paper, we reviewed droplet detection and active sorting methods that are currently still being widely used for high-through screening applications in microfluidic systems, including the latest updates regarding each technology. We analyze and summarize the merits and drawbacks of each presented technology and conclude, with our perspectives, on future direction of development.
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Affiliation(s)
- Can Huang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77842, USA
| | - Yuqian Jiang
- State Key Laboratory of Food Nutrition and Safety, College of Food Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Yuwen Li
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77842, USA
| | - Han Zhang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77842, USA
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Grytsyk N, Cianfarani D, Crégut O, Richert L, Boudier C, Humbert N, Didier P, Mély Y, Léonard J. Kinetics of protein-assisted nucleic acid interconversion monitored by transient time resolved fluorescence in microfluidic droplets. Nucleic Acids Res 2021; 49:e111. [PMID: 34450653 PMCID: PMC8565319 DOI: 10.1093/nar/gkab687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/29/2021] [Accepted: 08/24/2021] [Indexed: 11/25/2022] Open
Abstract
Interconversions between nucleic acid structures play an important role in transcriptional and translational regulation and also in repair and recombination. These interconversions are frequently promoted by nucleic acid chaperone proteins. To monitor their kinetics, Förster resonance energy transfer (FRET) is widely exploited using ensemble fluorescence intensity measurements in pre-steady-state stopped-flow experiments. Such experiments only provide a weighted average of the emission of all species in solution and consume large quantities of materials. Herein, we lift these limitations by combining time-resolved fluorescence (TRF) with droplet microfluidics (DmF). We validate the innovative TRF-DmF approach by investigating the well characterized annealing of the HIV-1 (+)/(–) Primer Binding Sequences (PBS) promoted by a HIV-1 nucleocapsid peptide. Upon rapid mixing of the FRET-labelled (–)PBS with its complementary (+)PBS sequence inside microdroplets, the TRF-DmF set-up enables resolving the time evolution of sub-populations of reacting species and reveals an early intermediate with a ∼50 ps donor fluorescence lifetime never identified so far. TRF-DmF also favorably compares with single molecule experiments, as it offers an accurate control of concentrations with no upper limit, no need to graft one partner on a surface and no photobleaching issues.
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Affiliation(s)
- Natalia Grytsyk
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg & CNRS, 67034 Strasbourg, France.,Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 67401 Illkirch, France
| | - Damien Cianfarani
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg & CNRS, 67034 Strasbourg, France
| | - Olivier Crégut
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg & CNRS, 67034 Strasbourg, France
| | - Ludovic Richert
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 67401 Illkirch, France
| | - Christian Boudier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 67401 Illkirch, France
| | - Nicolas Humbert
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 67401 Illkirch, France
| | - Pascal Didier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 67401 Illkirch, France
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de Pharmacie, 67401 Illkirch, France
| | - Jérémie Léonard
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg & CNRS, 67034 Strasbourg, France
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Lifetime encoding in flow cytometry for bead-based sensing of biomolecular interaction. Sci Rep 2020; 10:19477. [PMID: 33173064 PMCID: PMC7655863 DOI: 10.1038/s41598-020-76150-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/07/2020] [Indexed: 12/19/2022] Open
Abstract
To demonstrate the potential of time-resolved flow cytometry (FCM) for bioanalysis, clinical diagnostics, and optically encoded bead-based assays, we performed a proof-of-principle study to detect biomolecular interactions utilizing fluorescence lifetime (LT)-encoded micron-sized polymer beads bearing target-specific bioligands and a recently developed prototype lifetime flow cytometer (LT-FCM setup). This instrument is equipped with a single excitation light source and different fluorescence detectors, one operated in the photon-counting mode for time-resolved measurements of fluorescence decays and three detectors for conventional intensity measurements in different spectral windows. First, discrimination of bead-bound biomolecules was demonstrated in the time domain exemplarily for two targets, Streptavidin (SAv) and the tumor marker human chorionic gonadotropin (HCG). In a second step, the determination of biomolecule concentration levels was addressed representatively for the inflammation-related biomarker tumor necrosis factor (TNF-α) utilizing fluorescence intensity measurements in a second channel of the LT-FCM instrument. Our results underline the applicability of LT-FCM in the time domain for measurements of biomolecular interactions in suspension assays. In the future, the combination of spectral and LT encoding and multiplexing and the expansion of the time scale from the lower nanosecond range to the longer nanosecond and the microsecond region is expected to provide many distinguishable codes. This enables an increasing degree of multiplexing which could be attractive for high throughput screening applications.
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Hung ST, Mukherjee S, Jimenez R. Enrichment of rare events using a multi-parameter high throughput microfluidic droplet sorter. LAB ON A CHIP 2020; 20:834-843. [PMID: 31974539 PMCID: PMC7135947 DOI: 10.1039/c9lc00790c] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
High information content analysis, enrichment, and selection of rare events from a large population are of great importance in biological and biomedical research. The fluorescence lifetime of a fluorophore, a photophysical property which is independent of and complementary to fluorescence intensity, has been incorporated into various imaging and sensing techniques through microscopy, flow cytometry and droplet microfluidics. However, the throughput of fluorescence lifetime activated droplet sorting is orders of magnitude lower than that of fluorescence activated cell sorting, making it unattractive for applications such as directed evolution of enzymes, despite its highly effective compartmentalization of library members. We developed a microfluidic sorter capable of selecting fluorophores based on fluorescence lifetime and brightness at two excitation and emission colors at a maximum droplet rate of 2.5 kHz. We also present a novel selection strategy for efficiently analyzing and/or enriching rare fluorescent members from a large population which capitalizes on the Poisson distribution of analyte encapsulation into droplets. The effectiveness of the droplet sorter and the new selection strategy are demonstrated by enriching rare populations from a ∼108-member site-directed mutagenesis library of fluorescent proteins expressed in bacteria. This selection strategy can in principle be employed on many droplet sorting platforms, and thus can potentially impact broad areas of science where analysis and enrichment of rare events is needed.
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Affiliation(s)
- Sheng-Ting Hung
- JILA, NIST and University of Colorado, Boulder, Colorado 80309, USA.
| | - Srijit Mukherjee
- JILA, NIST and University of Colorado, Boulder, Colorado 80309, USA. and Department of Chemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Ralph Jimenez
- JILA, NIST and University of Colorado, Boulder, Colorado 80309, USA. and Department of Chemistry, University of Colorado, Boulder, Colorado 80309, USA
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Kage D, Hoffmann K, Nifontova G, Krivenkov V, Sukhanova A, Nabiev I, Resch-Genger U. Tempo-spectral multiplexing in flow cytometry with lifetime detection using QD-encoded polymer beads. Sci Rep 2020; 10:653. [PMID: 31959852 PMCID: PMC6971033 DOI: 10.1038/s41598-019-56938-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 12/18/2019] [Indexed: 01/09/2023] Open
Abstract
Semiconductor quantum dots (QDs) embedded into polymer microbeads are known to be very attractive emitters for spectral multiplexing and colour encoding. Their luminescence lifetimes or decay kinetics have been, however, rarely exploited as encoding parameter, although they cover time ranges which are not easily accessible with other luminophores. We demonstrate here the potential of QDs made from II/VI semiconductors with luminescence lifetimes of several 10 ns to expand the lifetime range of organic encoding luminophores in multiplexing applications using time-resolved flow cytometry (LT-FCM). For this purpose, two different types of QD-loaded beads were prepared and characterized by photoluminescence measurements on the ensemble level and by single-particle confocal laser scanning microscopy. Subsequently, these lifetime-encoded microbeads were combined with dye-encoded microparticles in systematic studies to demonstrate the potential of these QDs to increase the number of lifetime codes for lifetime multiplexing and combined multiplexing in the time and colour domain (tempo-spectral multiplexing). These studies were done with a recently developed novel luminescence lifetime flow cytometer (LT-FCM setup) operating in the time-domain, that presents an alternative to reports on phase-sensitive lifetime detection in flow cytometry.
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Affiliation(s)
- Daniel Kage
- Federal Institute for Materials Research and Testing (BAM), Biophotonics Division 1.2, Richard-Willstätter-Str. 11, D-12489, Berlin, Germany.,Department of Physics, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489, Berlin, Germany
| | - Katrin Hoffmann
- Federal Institute for Materials Research and Testing (BAM), Biophotonics Division 1.2, Richard-Willstätter-Str. 11, D-12489, Berlin, Germany
| | - Galina Nifontova
- Laboratory of Nano-bioengineering, National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409, Moscow, Russian Federation
| | - Victor Krivenkov
- Laboratory of Nano-bioengineering, National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409, Moscow, Russian Federation
| | - Alyona Sukhanova
- Laboratoire de Recherche en Nanosciences, LRN-EA4682, Université de Reims Champagne-Ardenne, 51100, Reims, France
| | - Igor Nabiev
- Laboratory of Nano-bioengineering, National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 115409, Moscow, Russian Federation.,Laboratoire de Recherche en Nanosciences, LRN-EA4682, Université de Reims Champagne-Ardenne, 51100, Reims, France.,Sechenov First Moscow State Medical University, 119991, Moscow, Russian Federation
| | - Ute Resch-Genger
- Federal Institute for Materials Research and Testing (BAM), Biophotonics Division 1.2, Richard-Willstätter-Str. 11, D-12489, Berlin, Germany.
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Hasan S, Geissler D, Wink K, Hagen A, Heiland JJ, Belder D. Fluorescence lifetime-activated droplet sorting in microfluidic chip systems. LAB ON A CHIP 2019; 19:403-409. [PMID: 30604804 DOI: 10.1039/c8lc01278d] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present a highly efficient microfluidic fluorescence lifetime-activated droplet sorting (FLADS) approach as a novel technology for droplet manipulation in lab-on-a-chip devices. In a proof-of-concept study, we successfully applied the approach to sort droplets containing two different fluorescent compounds on the basis of their corresponding fluorescence lifetime. Towards this end, a technical set-up was developed enabling on-the-fly fluorescence lifetime determination of passing droplets. The herein developed LabVIEW program enabled fast triggering of a downstream dielectrophoretic force sorting functionality depending on average fluorescence lifetimes of individual droplets. The approach worked reliably at individual substrate concentrations from 1 nM to 1 mM. This not only allowed reliable sorting of droplets containing species with different fluorescence lifetimes but also enabled differentiation of mixtures in individual droplets.
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Affiliation(s)
- Sadat Hasan
- Institute of Analytical Chemistry, Leipzig University, Linnéstraße 3, 04103 Leipzig, Germany.
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10
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Kage D, Hoffmann K, Wittkamp M, Ameskamp J, Göhde W, Resch-Genger U. Luminescence lifetime encoding in time-domain flow cytometry. Sci Rep 2018; 8:16715. [PMID: 30425307 PMCID: PMC6233182 DOI: 10.1038/s41598-018-35137-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 10/30/2018] [Indexed: 01/04/2023] Open
Abstract
Time-resolved flow cytometry represents an alternative to commonly applied spectral or intensity multiplexing in bioanalytics. At present, the vast majority of the reports on this topic focuses on phase-domain techniques and specific applications. In this report, we present a flow cytometry platform with time-resolved detection based on a compact setup and straightforward time-domain measurements utilizing lifetime-encoded beads with lifetimes in the nanosecond range. We provide general assessment of time-domain flow cytometry and discuss the concept of this platform to address achievable resolution limits, data analysis, and requirements on suitable encoding dyes. Experimental data are complemented by numerical calculations on photon count numbers and impact of noise and measurement time on the obtained lifetime values.
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Affiliation(s)
- Daniel Kage
- Federal Institute for Materials Research and Testing (BAM), Biophotonics Division 1.2, Richard-Willstätter-Str. 11, D-12489, Berlin, Germany
- Department of Physics, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489, Berlin, Germany
| | - Katrin Hoffmann
- Federal Institute for Materials Research and Testing (BAM), Biophotonics Division 1.2, Richard-Willstätter-Str. 11, D-12489, Berlin, Germany
| | - Marc Wittkamp
- Quantum Analysis GmbH, Mendelstraße 17, D-48149, Münster, Germany
| | - Jens Ameskamp
- Quantum Analysis GmbH, Mendelstraße 17, D-48149, Münster, Germany
| | - Wolfgang Göhde
- Quantum Analysis GmbH, Mendelstraße 17, D-48149, Münster, Germany
| | - Ute Resch-Genger
- Federal Institute for Materials Research and Testing (BAM), Biophotonics Division 1.2, Richard-Willstätter-Str. 11, D-12489, Berlin, Germany.
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11
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Affiliation(s)
- David J S Birch
- Photophysics Group, Department of Physics, University of Strathclyde, Scottish Universities Physics Alliance, Glasgow G4 0NG, Scotland, United Kingdom
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