Technology

Home / Technology

A unique combination of three technologies lies at the heart of rqmicro‘s rapid test method:

Connected devices

Actionable data

Point-of-use testing

Automated water analysis

Immunomagnetic Separation

The rqmicro CellStream instrument isolates and purifies target cells via magnetic particles that are coupled to highly specific proprietary antibodies. In contrast to conventional IMS methods, our automated approach separates target cells contact-free in a continuous process on a disposable microfluidic cartridge, guaranteeing easy handling and low maintenance.

After a filtration step, the sample is resuspended in a small volume of buffer and two types of specific antibodies, produced by rqmicro, are added.

One mix contains antibodies bound to magnetic particles. They will bind to the target cells and thereby enable the immunomagnetic separation. The second mix contains antibodies bound to a fluorescent dye that allows for quantification with a standard flow cytometer after the immunomagnetic separation.

During the immunomagnetic separation, a magnet is lowered down and thereby immobilizes the target cells which are bound to magnetic particles. At the same time more than 95% of the competing flora, originally present in the sample, is directed to the waste fraction. Due to a washing step, the sample purity reaches up to 99%.

Microfluidics

rqmicro uses the great potential of microfluidics to deliver a product that allows for a highly efficient separation and purification of target cells from samples of varying complexity using immunomagnetic separation (IMS). As the sample passes through a narrow channel in the microfluidic cartridge, target cells are isolated and resuspended in clean buffer solution. This positive fraction can be analyzed by flow cytometry or any method of analysis by your choice.

After incubation the sample is loaded onto a disposable rqmicro cartridge together with the washing buffer.

The cartridge is then placed into the CellStream instrument where a magnetic field and vacuum pumps create the environment needed for a fast and effective purification of the sample.

The channel in the center of the cartridge allows for a precise immunomagnetic separation. During the process, the purified and concentrated target cells are transferred to the right side of the cartridge and are eluted in clean buffer while at the same time, the rest of the sample is directed to the waste fraction.

Flow Cytometry

The rqmicro method for sample preparation  works in combination with the analytical method of your choice such as PCR, cultivating cells on agar plates, fluorescence microscopy, etc. The fastest and most precise detection method however is flow cytometry (FCM). Hence, rqmicro products are designed to empower your in-house flow cytometer to deliver reliable and fast results.

Flow cytometry is a laser-based technology for electronic cell counting that allows multiparametric analysis of the properties of thousands of cells per second. The cells labelled with a fluorescent dye pass in front of a laser in a stream of fluid. The laser excites electrons in the fluorescent dye that then return in fractions of a second to their previous state by emitting light. The FCM detects this light signal, which is then transformed into data that is analyzed by a computer using special software.

Flow cytometry tutorial

Since it is a cultivation-independent method, all fluorescence labelled cells present in a sample, also viable but non-culturable (VBNC) or dead cells are quantified by FCM in a matter of minutes.

After immunomagnetic separation, the positive fraction is transferred to fresh tubes. At this point, if a viability assessment is of interest, half of the sample can be transferred into a fresh tube and the rqmicro viability dye can be added.

Then the sample is ready to be analyzed with your flow cytometer. Depending on the instrument, the samples can be analyzed in tube-mode or also in 96-well-plates.

The total and viable cell count of the target cells can then be obtained in a matter of minutes. The cell population is usually visualized in a dot plot.