Busting miths about reagent injectors
Learn more about injector qualities that have a direct impact on the performance of the assay.
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We often get asked the question what to consider when talking about the ″ideal injector”. So, let's first take a look at what we would consider to be important when taking a closer look at injectors and then compare different types of injectors against those parameters:
As you will see in the following, all injectors are not created equal. Take a look at Table 1 for a detailed comparison. Starting with a high-level view, two different designs are used, based on either syringe or bellows. What these injectors have in common is that they use a stepper motor and a 3-way solenoid valve to direct the flow of the liquid.
|Syringe-based Injector||JET Injector|
|Injection accuracy & reproducibility|
But potential accuracy issues when injecting small volumes. Accuracy for 10µl can be as low as just 90%
98% over the entire volume range.
|Time required per injection||Many syringe type injectors cannot perform ultra-fast injections with adequate mixing to capture the first 150ms of a kinetic assay.||Ultra-fast injection enabling the measurement of the first 150ms of a kinetic assay.|
High dead volume.
Need to be primed up to 5 times their volume to achieve a 99% homogeneous mix at the tip.
Low dead volume.
Recovers up to 60% of the reagent in the injector line. A single priming sequence is sufficient to achieve a 99% homogeneous mix at the tip.
Syringe based injectors are very expensive (typically >$3,000 each).
Tend to wear out over time due to friction and need to be replaced.
Frictionless operation for extended lifetime.
Typically, more than 3 million injections without mechanical failure.
|Design & additional functions||Material mix that can produce stronger shear forces.||100% Teflon resulting in negligible shear forces enabling injection of cell suspensions.|
The syringe-based injector is by far the most common type of injector being used today. This type of injector contains a syringe and a Teflon coated barrel. The piston moves within the glass syringe which can cause friction, resulting in increased maintenance costs.
On the other hand, mostfrom Berthold Technologies use up to 3 software-controlled JET Injectors which, as detailed above, have many advantages that are relevant in many types of assays. A sophisticated Prime Mode reduces the reagent consumption while ensuring homogeneous filling. JET Injectors are built for extreme longevity and fast injection times to guarantee very efficient mixing.