Flow Cytometry on a Chip

Kiesel, P.; Martini, Joerg; Recht, Michael I.; Bern, Marshall; Johnson, N. M.; Huck, Malte

doi:10.1007/978-3-642-29268-2_3

Cited by 3 publications

(4 citation statements)

References 44 publications

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“…7 However, many rural areas, for example in Sub-Saharan Africa, the region most affected by HIV, do not have access to CD4 counting as they often lack the necessary infrastructure to ship blood samples to central labs and get the result back to the patient. Accordingly, there have been large efforts over the last decade 8 to miniaturize flow cytometers [9][10][11][12][13] or to develop alternative portable tests that can be carried out with minimal training, 7,14 for example LabNow, 15 PIMA (Alere), 16 Daktari, [17][18][19] Zyomyx. 20 Earlier, we developed a single platform image cytometer 21 that simplified the instrumentation and provided very promising results, [22][23][24] but still required precision for the sample preparation, which frequently cannot be met in the field by less experienced operators.…”

Section: Introductionmentioning

confidence: 99%

On-chip sample preparation by controlled release of antibodies for simple CD4 counting

Beck¹,

Brockhuis²,

Velde³

et al. 2012

Lab Chip

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We present a simple system for CD4 and CD8 counting for point-of-care HIV staging in low-resource settings. Automatic sample preparation is achieved through a dried reagent coating inside a thin (26 μm) counting chamber, allowing the delayed release of fluorochrome conjugated monoclonal antibodies after the filling of the chamber with whole blood by capillary flow. A custom-built image cytometer is used to capture fluorescence images representing more than 1 μl of blood. The thin layer of blood in combination with the large image area allows the use of whole blood from a finger prick without the need for dilution, lysis or cell enrichment. Automatic cell counting of CD4(+) and CD8(+) T-lymphocytes correlates well with results obtained by flow cytometry.

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Section: Introductionmentioning

confidence: 99%

On-chip sample preparation by controlled release of antibodies for simple CD4 counting

Beck¹,

Brockhuis²,

Velde³

et al. 2012

Lab Chip

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“…Currently, our system detects only a single color for each droplet. However, as has been previously shown by other groups on cell-based detection systems, 25,48 multicolor detection can be integrated with masked systems. The data acquisition electronics, which currently fundamentally limits the overall throughput to 10 4 drops min −1 , could be further improved (~50×) to exploit the high bandwidth of microelectronics.…”

Section: Discussionmentioning

confidence: 93%

Miniaturized, multiplexed readout of droplet-based microfluidic assays using time-domain modulation

et al. 2014

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Recent advances in microfluidics to generate and control picoliter emulsions of water in oil have enabled ultra-sensitive assays for small molecules, proteins, nucleic acids, and cells. Unfortunately, the conventional fluorescence detection used to measure the outcome of these droplet-based assays has not proven suited to match the time and space multiplexing capabilities of microfluidic systems. To address this challenge, we developed an in-flow fluorescence detection platform that enables multiple streams of droplets to be monitored using only a single photodetector and no lenses. The key innovation of our technology is the amplitude modulation of the signal from fluorescent droplets using distinct micro-patterned masks for each channel. By taking advantage of the high bandwidth of electronics, our technique enables the velocity-independent recovery of weak fluorescent signals (SNR ≪ 1) using only simple hardware, obviating the need for lasers, bulky detectors, and complex fluid control. We demonstrated a handheld-sized device that simultaneously monitors four independent channels with the capability to be scaled-up to more than sixteen, limited primarily by the droplet density.

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“…The size of flow cytometers has decreased significantly over time even when imaging capabilities such as digital microscopy on a cellphone [ 10 ] were incorporated to the systems. However, the complexity of their large optical trains, sensitivity, and power requirement has prevented them from being effectively used in harsh environments or portable point-of-care diagnostics [ 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

“…A handheld prototype of a flow cytometer which uses a PIN photodiode rather than a PMT is reported by Kiesel et al [ 12 ]. However the detection limit was about 200 molecules of equivalent phycoerythrin for 2 μm Rainbow calibration beads.…”

Section: Introductionmentioning

confidence: 99%

Multi-Pixel Photon Counters for Optofluidic Characterization of Particles and Microalgae

2015

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We have developed an optofluidic biosensor to study microscale particles and different species of microalgae. The system is comprised of a microchannel with a set of chevron-shaped grooves. The chevrons allows for hydrodynamic focusing of the core stream in the center using a sheath fluid. The device is equipped with a new generation of highly sensitive photodetectors, multi-pixel photon counter (MPPC), with high gain values and an extremely small footprint. Two different sizes of high intensity fluorescent microspheres and three different species of algae (Chlamydomonas reinhardtii strain 21 gr, Chlamydomonas suppressor, and Chlorella sorokiniana) were studied. The forward scattering emissions generated by samples passing through the interrogation region were carried through a multimode fiber, located in 135 degree with respect to the excitation fiber, and detected by a MPPC. The signal outputs obtained from each sample were collected using a data acquisition system and utilized for further statistical analysis. Larger particles or cells demonstrated larger peak height and width, and consequently larger peak area. The average signal output (integral of the peak) for Chlamydomonas reinhardtii strain 21 gr, Chlamydomonas suppressor, and Chlorella sorokiniana falls between the values found for the 3.2 and 10.2 μm beads. Different types of algae were also successfully characterized.

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Flow Cytometry on a Chip

Cited by 3 publications

References 44 publications

On-chip sample preparation by controlled release of antibodies for simple CD4 counting

On-chip sample preparation by controlled release of antibodies for simple CD4 counting

Miniaturized, multiplexed readout of droplet-based microfluidic assays using time-domain modulation

Multi-Pixel Photon Counters for Optofluidic Characterization of Particles and Microalgae

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