The FilteRing (“FR”) is a patent-pending filtration system designed to be used with an automated liquid handler, or with any manual pipettor. In either case, what makes the FR so unique is that it is specifically designed to work with any disposable pipet tip; the patent-pending FR is the first time in pipetting history that a disposable pipet tip has been used as a pickup tool.
However, by adding the FR to your robotic Automated Liquid Handler (“ALH”) workflow, you are providing your ALH robot with a new skill – on-deck real time (“RT”) filtration or concentration.
FILTERING RT ON-DECK FILTRATION
The typical approach when faced with samples that have solid material suspended in the liquid is to centrifuge them, driving the solid particles to the bottom of the sample tubes. While this approach works well enough, in many cases it is like driving in a nail with a sledgehammer…overkill.
In addition to centrifugation being overkill in many instances, a centrifugation step is not part of the ALH automated workflow. Therefore user intervention is required (bring samples to centrifuge/wait while samples spin/return to remove samples/return to ALH) which equates to slower throughput. Furthermore, additional manual handling of samples increases risk as well as variability in your assay. The less manual handling steps, the better the precision and accuracy.
The fact is, that in many instances, driving suspended material to the bottom of the tube is not needed; pressing them down far enough to provide sufficient volume for aliquoting your volume of clarified sample is all that is required. That is precisely what the FR does.
FILTERING RT ON-DECK CONCENTRATION
The FilteRing (“FR”) has a second functionality in addition to trapping particulate matter below itself. The FR is also able to concentrate samples for you, in a completely walk-away automated fashion.
To explain by way of an example: Let’s say you have suspended cells in a tube that has 5 ml of sample. You would like to concentrate that sample down to a final volume of 500 microliters, providing a 10-fold concentration of the suspended cells.
When the FR is pressed into the sample tube, as it moves down through the liquid, it is compressing the cells beneath it. Once it reaches its stopping point, there would now be 4.5 ml of clarified liquid above the FR and 500 microliters of concentrated cells below. The robot would then aspirate a volume of concentrated cells from below the FR to use for the assay.
WHAT MAKES UP THE FILTERING?
(NOTE: Please use the below details as callouts associated with the exploded view. Use the video as a guide for pointing to different parts. Let me know if you have any questions)
Within the FR is a circle of filter media. This is the one variable associated with the FR – it uses filter media that you choose based on either what you are currently using, or what you would choose for sample clarification now that your ALH has a new on-deck filtration skill. If you do not specify a particular filter type, the FR will come with a 20u filtration membrane typically used for general-purpose sample clarification.
The filter media is held in place by an Upper Body and Lower Body designed with “pizza slice” openings allowing liquid to flow through the filter material.
Around the circumference of the FR extends out a silicone Wiper. This makes contact with the wall of the sample tube in order to ensure all liquid flows through the FR, not around it. The Wiper plays an additional role as a septum. The Central Slit of the Wiper keeps any material below the FR from accidentally flowing back up through the central opening, a valuable feature that keeps the upper liquid clear of any interferences that are trapped below.
With respect to the sample tube – the initial FR release is designed to work with a typical 50ml conical centrifuge tube (yes, the irony of using a centrifuge tube is not lost on us; however, it is an industry-standard tube used for many applications which is why we chose that form factor). For FRs where you would require a different diameter for a different type of sample tube, please inquire with your specifications by sending a message from the Contact Us page.
(image courtesy of Amazon.com)
7.1 mm height
Center orifice designed to accommodate a variety of disposable pipet tips
Internal Wiper has central slit to act as septum to mitigate backflush
Note: We don’t specify filtration or concentration flow rates/FR speeds as these will vary with application. Reach out to us on the Contact page to discuss this in more detail.