What is Flow Cytometry?
Generally, flow cytometry is the measurement of single cells in a water jet.
We use flow cytometry routinely to quantify picoplankton samples and cell cultures. Pigments like chlorophyll and carotenoids characteristic for marine cyanobacteria and microalgae are detected as well as fluorescent dyes specific for DNA, proteins and other cellular compounds of microorganisms.
Further, cells meeting predefined properties can be sorted with high speed for further analysis.
A simplified illustration of Flow Cytometry is given on the right.
Briefly, cells suspended in the sample are injected into a sheath fluid (top). Through the nozzle cells are focused into the center of the water jet. After leaving the nozzle cells are passing by the laser light in a single file like pearls on a string. The signals of the cells are recorded through detectors by a computing unit. Cells meeting defined parameters in the break-off point will be charged in their water droplet. The resulting charged droplet will be deflected into a vial. Depicted here is a two-way sort of two differently stained cell populations. Please refer to the literature for further details.
The Accuri is our small cell analyser suitable for cell counting of cultures and other samples. It is robust, quick in set up and easy to handle. Sensitivity is sufficient for most marine samples. It has one blue-green laser and four detectors.
The small benchtop flow cytometer can be used for shipboard analysis of picoplankton and for a sorting radioactively-labeled microorganisms for down-stream analysis. Because of its cuvette-based analysis system, it is a very sensitive system. The closed mechanic sort system makes it a safe system to work with radioactive material.
This large research flow cytometer is used for high speed sorting of cell material for e.g. 16S rRNA cloning and genome sequencing. Currently the machine is being technically upgraded and relocated to the Biological Station (BAH) of the Alfred Wegener Institute (AWI) at Helgoland, North Sea. There, at the long-term ecological station, fresh material can be sorted within an hour after sampling for further processing.
BD Influx Mariner
The Influx is the next-gen flow sorter for high-speed cell sorting for e.g. genome analyses. It is a stream in air sorter with a high sensitivity forward scatter detector, two lasers (UV and blue) and two octagon detection units.
Since the machine is built on a robust frame on rolls, it is suitable for on-board usage.
The robotic sampler can be used for a wide variety of collection vials from small PCR tubes to 384 multititer plates to microscope slides.
Analysis rates are typically between 1,000 - 10,000 events per second, sort rates depend on the target cells and reach up to 1000 per second. Using optimal settings, the purity is typically >99%.