The Experts below are selected from a list of 12651 Experts worldwide ranked by ideXlab platform

Philippe Renaud - One of the best experts on this subject based on the ideXlab platform.

  • dielectrophoretic sorting on a microfabricated Flow Cytometer label free separation of babesia bovis infected erythrocytes
    Bioelectrochemistry, 2008
    Co-Authors: Elisabete Nascimento, Philippe Renaud, Nicolas Demierre, Tiago Silva, Thomas Braschler, Nuno Nogueira, Abel Oliva
    Abstract:

    Dielectrophoresis is a method that has demonstrated great potential in cell discrimination and isolation. In this study, the dielectrophoretic sorting of normal and Babesia bovis infected erythrocytes was performed using a microfabricated Flow Cytometer. Separation was possible through exploitation of the dielectric differences between normal and infected erythrocytes, essentially due to the higher ionic membrane permeability of B. bovis infected cells. Sorting experiments were performed inside a microchip made from Pt microelectrodes and SU-8 channels patterned on a glass substrate. Optimum cell separation was achieved at 4 MHz using an in vitro culture of B. bovis suspended in 63 mS/m phosphate buffer and applying a sinusoidal voltage of 15 V peak-to-peak. Normal erythrocytes experienced stronger positive dielectrophoresis (pDEP) than B. bovis infected cells, moving them closer to the microelectrodes. Under these conditions it was possible to enrich the fraction of infected cells from 7 to 50% without the need of extensive sample preparation or labelling. Throughout the experiments very few microliters of sample were used, suggesting that this system may be considered suitable for integration in a low-cost automated device to be used in the in situ diagnostic of babesiosis.

  • label free detection of babesia bovis infected red blood cells using impedance spectroscopy on a microfabricated Flow Cytometer
    Acta Tropica, 2007
    Co-Authors: Claudia Kuttel, Philippe Renaud, Elisabete Nascimento, Nicolas Demierre, Tiago Silva, Thomas Braschler, Abel Oliva
    Abstract:

    Impedance spectroscopy is a powerful tool for label-free analysis and characterisation of living cells. In this work, we achieved the detection of Babesia bovis infected red blood cells using impedance spectroscopy on a microfabricated Flow Cytometer. The cellular modifications caused by the intracellular parasite result in a shift in impedance which can be measured dielectrically. Thus, a rapid cell-by-cell detection with microliter amounts of reagents is possible. Unlike other diagnostic tests, this method does not depend on extensive sample pre-treatment or expensive chemicals and equipment.

  • impedance spectroscopy Flow cytometry on chip label free cell differentiation
    Cytometry Part A, 2005
    Co-Authors: Karen C Cheung, Shady Gawad, Philippe Renaud
    Abstract:

    Background: The microfabricated impedance spectroscopy Flow Cytometer used in this study permits rapid dielectric characterization of a cell population with a simple microfluidic channel. Impedance measurements over a wide frequency range provide information on cell size, membrane capacitance, and cytoplasm conductivity as a function of frequency. The amplitude, opacity, and phase information can be used for discrimination between different cell populations without the use of cell markers. Methods: Polystyrene beads, red blood cells (RBCs), ghosts, and RBCs fixed in glutaraldehyde were passed through a microfabricated Flow Cytometer and measured individually by using two simultaneously applied discrete frequencies. The cells were characterized at 1,000 per minute in the frequency range of 350 kHz to 20 MHz. Results: Cell size was easily measured with submicron accuracy. Polystyrene beads and RBCs were differentiated using opacity. RBCs and ghosts were differentiated using phase information, whereas RBCs and fixed RBCs were differentiated using opacity RBCs fixed using increasing concentrations of glutaraldehyde showed increasing opacity. This increased opacity was linked to decreased cytoplasm conductivity and decreased membrane capacitance, both resulting from protein cross-linking. Conclusions: This work presents label-free differentiation of cells in an on- chip Flow Cytometer based on impedance spectroscopy, which will be a powerful tool for cell characterization. (c) 2005 Wiley-Liss, Inc.

M M Davidson - One of the best experts on this subject based on the ideXlab platform.

  • testing by sysmex uf 100 Flow Cytometer and with bacterial culture in a diagnostic laboratory a comparison
    Journal of Clinical Pathology, 2006
    Co-Authors: R Evans, M M Davidson
    Abstract:

    A large proportion of the samples tested in routine diagnostic microbiology laboratory are urine samples. The gold standard is bacterial culture, but a high proportion of samples cultured are negative. Unnecessary testing can be reduced and an improved service provided by an effective screening test. The Sysmex UF-100 Flow Cytometer has been developed to count cells and casts accurately in urine samples. Its performance in a screening test was compared with bacterial culture by using 1005 consecutive urine samples, and cut-off criteria were established. Cut-off values of 3000 bacteria/μl and 111 WBC/μl provided the best discrimination. Of 1005 samples, 606 (60%) would be cultured. Sixteen samples that were not selected according to these criteria were culture positive. This was considered acceptable for our routine use. The use of a testing algorithm incorporating the Sysmex UF-100 Flow Cytometer has improved the quality and efficiency of urine testing within the routine microbiology laboratory.

Drew A Hall - One of the best experts on this subject based on the ideXlab platform.

  • an aptamer based magnetic Flow Cytometer using matched filtering
    Biosensors and Bioelectronics, 2020
    Co-Authors: Chihcheng Huang, Partha Ray, Matthew Chan, Xiahan Zhou, Drew A Hall
    Abstract:

    Abstract Facing unprecedented population-ageing, the management of noncommunicable diseases (NCDs) urgently needs a point-of-care (PoC) testing infrastructure. Magnetic Flow Cytometers are one such solution for rapid cancer cellular detection in a PoC setting. In this work, we report a giant magnetoresistive spin-valve (GMR SV) biosensor array with a multi-stripe sensor geometry and matched filtering to improve detection accuracy without compromising throughput. The carefully designed sensor geometry generates a characteristic signature when cells labeled with magnetic nanoparticles (MNPs) pass by thus enabling multi-parametric measurement like optical Flow Cytometers (FCMs). Enumeration and multi-parametric information were successfully measured across two decades of throughput (37 — 2730 cells/min). 10-μm polymer microspheres were used as a biomimetic model where MNPs and MNP-decorated polymer conjugates were Flown over the GMR SV sensor array and detected with a signal-to-noise ratio (SNR) as low as 2.5 dB due to the processing gain afforded by the matched filtering. The performance was compared against optical observation, exhibiting a 92% detection efficiency. The system achieved a 95% counting accuracy for biomimetic models and 98% for aptamer-based pancreatic cancer cell detection. This system demonstrates the ability to perform reliable Flow cytometry toward PoC diagnostics to benefit NCD control plans.

  • an aptamer based magnetic Flow Cytometer using matched filtering
    bioRxiv, 2020
    Co-Authors: Chihcheng Huang, Partha Ray, Matthew Chan, Xiahan Zhou, Drew A Hall
    Abstract:

    Facing unprecedented population-ageing, the management of noncommunicable diseases (NCDs) urgently needs a point-of-care (PoC) testing infrastructure. Magnetic Flow Cytometers are one such solution for rapid cancer cellular detection in a PoC setting. In this work, we report a giant magnetoresistive spin-valve (GMR SV) biosensor array with a multi-stripe sensor geometry and matched filtering to improve detection accuracy without compromising throughput. The carefully designed sensor geometry generates a characteristic signature when cells labeled with magnetic nanoparticles (MNPs) pass by thus enabling multi-parametric measurement like optical Flow Cytometers (FCMs). Enumeration and multi-parametric information were successfully measured across two decades of throughput. 10-μm polymer microspheres were used as a biomimetic model where MNPs and MNP-decorated polymer conjugates were Flown over the GMR SV sensor array and detected with a signal-to-noise ratio (SNR) as low as 2.5 dB due to the processing gain afforded by the matched filtering. The performance was compared against optical observation, exhibiting a 92% detection efficiency. The system achieved a 95% counting accuracy for biomimetic models and 98% for aptamer-based pancreatic cancer cell detection. This system demonstrates the ability to perform reliable PoC diagnostics towards the benefit for NCD control plans.

  • a gmr based magnetic Flow Cytometer using matched filtering
    IEEE Sensors, 2017
    Co-Authors: Chihcheng Huang, Xiahan Zhou, Da Ying, Drew A Hall
    Abstract:

    In this work, signal processing techniques such as matched filtering and cross-correlation were applied to improve the detection efficiency in magnetic Flow cytometry measurements with a SNR as low as 4.5 dB, a 3-fold improvement over thresholding alone. A multi-stripe GMR sensor was fabricated to improve the discrimination between magnetic nanoparticles (MNPs) and interference/noise such as motion artifacts. Time-of-flight between successive sensors in the array enables multiparametric and hydrodynamic analysis of cells. Detection of 4.5 pm MNPs and polymer microbeads decorated with MNPs, serving as a biomimetic model of cells, shows proof-of-principle. This setup was then optimized for future cell detection experiments.

Yuanyuan Han - One of the best experts on this subject based on the ideXlab platform.

  • 2d image guided cell sorter and 3d imaging Flow Cytometer
    High-Speed Biomedical Imaging and Spectroscopy V, 2020
    Co-Authors: Rui Tang, Yuanyuan Han, Xinyu Chen, Alex Ce Zhang, Zunming Zhang, Lauren Waller, Jiajie Chen, Changhung Lee, Ivan Gagne, Sung-hwan Cho
    Abstract:

    Cell type classification and isolation according to imaging and spatial characteristics, beyond traditional fluorescently labeled biomarkers, enable the development of new biological insight and establishment of connections between phenotypical, morphological, and genomic cell information in normal and diseased states. Here we demonstrate a 2D image-guided cell sorter and a 3D imaging Flow Cytometer using fast scanning laser excitation sources. Both systems feature a cameraless design, which reconstructs cell images from the temporal readout of photomultiplier tubes.

  • imaging Flow Cytometer and image guided cell sorter
    OSA Advanced Photonics Congress (AP) 2019 (IPR Networks NOMA SPPCom PVLED) (2019) paper ITh3A.3, 2019
    Co-Authors: Rui Tang, Xinyu Chen, Yuanyuan Han
    Abstract:

    We discuss techniques that integrate microscopy and Flow Cytometer cell sorter into a single system. Both 2D and 3D images of individual cells are obtained in real time for cell calssification and isolation for downstream molecular analysis.

  • Imaging Cells in Flow Cytometer Using Spatial-Temporal Transformation
    Scientific Reports, 2015
    Co-Authors: Yuanyuan Han, Yu-hwa Lo
    Abstract:

    Flow Cytometers measure fluorescence and light scattering and analyze multiple physical characteristics of a large population of single cells as cells Flow in a fluid stream through an excitation light beam. Although Flow Cytometers have massive statistical power due to their single cell resolution and high throughput, they produce no information about cell morphology or spatial resolution offered by microscopy, which is a much wanted feature missing in almost all Flow Cytometers. In this paper, we invent a method of spatial-temporal transformation to provide Flow Cytometers with cell imaging capabilities. The method uses mathematical algorithms and a spatial filter as the only hardware needed to give Flow Cytometers imaging capabilities. Instead of CCDs or any megapixel cameras found in any imaging systems, we obtain high quality image of fast moving cells in a Flow Cytometer using PMT detectors, thus obtaining high throughput in manners fully compatible with existing Cytometers. To prove the concept, we demonstrate cell imaging for cells travelling at a velocity of 0.2 m/s in a microfluidic channel, corresponding to a throughput of approximately 1,000 cells per second.

Lukas Bestmann - One of the best experts on this subject based on the ideXlab platform.

  • automated urinalysis first experiences and a comparison between the iris iq200 urine microscopy system the sysmex uf 100 Flow Cytometer and manual microscopic particle counting
    Clinical Chemistry and Laboratory Medicine, 2007
    Co-Authors: Noushin Shayanfar, Ulrich Tobler, Arnold Von Eckardstein, Lukas Bestmann
    Abstract:

    BACKGROUND: Automated analysis of insoluble urine components can reduce the workload of conventional microscopic examination of urine sediment and is possibly helpful for standardization. We compared the diagnostic performance of two automated urine sediment analyzers and combined dipstick/automated urine analysis with that of the traditional dipstick/microscopy algorithm. METHODS: A total of 332 specimens were collected and analyzed for insoluble urine components by microscopy and automated analyzers, namely the Iris iQ200 (Iris Diagnostics) and the UF-100 Flow Cytometer (Sysmex). RESULTS: The coefficients of variation for day-to-day quality control of the iQ200 and UF-100 analyzers were 6.5% and 5.5%, respectively, for red blood cells. We reached accuracy ranging from 68% (bacteria) to 97% (yeast) for the iQ200 and from 42% (bacteria) to 93% (yeast) for the UF-100. The combination of dipstick and automated urine sediment analysis increased the sensitivity of screening to approximately 98%. CONCLUSIONS: We conclude that automated urine sediment analysis is sufficiently precise and improves the workFlow in a routine laboratory. In addition, it allows sediment analysis of all urine samples and thereby helps to detect pathological samples that would have been missed in the conventional two-step procedure according to the European guidelines. Although it is not a substitute for microscopic sediment examination, it can, when combined with dipstick testing, reduce the number of specimens submitted to microscopy. Visual microscopy is still required for some samples, namely, dysmorphic erythrocytes, yeasts, Trichomonas, oval fat bodies, differentiation of casts and certain crystals.