Successful Forensic Lab Automation: The Journey to Modularity

Written by: Kevin W.P. Miller, Ph.D., Hamilton Company

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In a previous ISHI Report article titled, “Successful Forensic Lab Automation Starts Here” we discussed practical insights to help you to develop a healthy automated ecosystem within your forensic DNA laboratory. After one year, some of you have taken the insights to heart as you developed and reaped the benefits of your own automated ecosystems. Congratulations!

Others, it seems, may remain hesitant to jump into this new automated world; or even the first step that involves taking a modular approach. This journey to modularity doesn’t have to instill feelings of dread, and we are here to guide you through the path.

First, let’s set the stage.

Think Modular

As you may recall from the previous article, modularity is about choosing universal robotic solutions that reduce touch points from one step to the next within a given workflow while also increasing reproducibility. Universal robotic platforms expand the contribution that each instrument can make to an overall workflow, therefore decreasing the number of instruments required. Modular instruments also share common deck accessories, programming language, and even consumable products, enabling flexibility in assay chemistry choice and workflow direction. This enhances the lifespan of your capital purchase.

“We already validated our semi-automated workflow that includes instruments dedicated to a single step,” I hear you say. “It works just fine, so what’s the benefit of replacing instruments now?”

Good question, and the answer lies with the samples coming into your lab.

Consistency is key to successful automation, and when it comes to the forensic DNA lab, consistent sample type, dependable parameters, and documented environmental conditions are the stuff of – dreams! We all know that the only thing that is consistent about evidentiary samples is that they are not at all consistent. Rather, they are challenging on so many levels.

DNA is more difficult to extract from some evidence types compared to others. Limited supply, environmental exposure, substrate interference, and even collection technique can add additional challenges to the successful extraction of high yield, high quality DNA from samples. So how is that dedicated “plug-and-play” automated extraction platform working for you in context of sample variety and challenges?

Think Fresh

Perhaps a transition to a plug-and-play system is how you start your journey to modularity. It’s a longer journey, but it may alleviate anxiety among those who dread the idea of automation. In this case, we can still help you to improve capabilities, capacity, and functionality compared to your current instrument or manual method.

The ID NIMBUS Presto assay ready workstation from Hamilton Company can be used as a plug-and-play system for automated sample extraction and purification or incorporated into a more-encompassing automated DNA sample processing workflow. It performs the same nucleotide extraction processes that you know and love, but wait, there’s more…there are two important twists.

First, ID NIMBUS Presto works with the Applied Biosystems™ PrepFiler™ Automated Forensic DNA Extraction Kit as well as the Applied Biosystems™ PrepFiler™ BTA Automated Forensic DNA Extraction Kit, both from Thermo Fisher Scientific. As you know, the former assay chemistry is used for a broad range of evidentiary DNA samples, while the latter is especially suited for use with samples that are calcified (bone and teeth) or that include adhesives (cigarette butts, tape lifts, envelope flaps). Both assay chemistries use uniquely structured magnetic particles and a multi-component surface chemistry to extract high yield, high quality DNA, but now they can be performed on a single instrument in batches of up to 96 samples at a time.

Second, the Thermo Scientific™ KingFisher™ Presto Purification System is mounted on the ID NIMBUS Presto deck. The KingFisher Presto system was designed in concert with the assay chemistry’s unique nature. Here, rods sheathed in a disposable tip comb transfer magnetic beads bound with DNA from lysed samples to plates containing specific reagents. By moving magnetic particle-affixed samples instead of liquids, DNA moves from one clean reagent to the next. At the same time, fresh reagents are independently pipetted to labware in a “just-in-time” fashion, enabling next steps in the procedure.

Together, all of this means that DNA extraction is rapidly completed, regardless of the nature of the starting material.

The ID NIMBUS Presto processes sample volumes ranging from 50 – 5000 µL, and is pre-programmed for use with both extraction chemistries. This latter feature is important for three reasons.

The first is a matter of time. Pre-programmed protocols developed in collaboration with the chemistry manufacturer help to ease assay setup and streamline internal laboratory validation requirements.

The second reason is a matter of convenience and cost-management. By enabling the processing of two kit chemistries on one automated workstation, the entire range of forensic samples – from simple to challenging – can be extracted on a single unit. Forensic labs don’t have to incur the cost, maintenance and service requirements, and physical space needs of separate, dedicated systems for each assay chemistry.

The third reason supports our advice – Don't Let Your Samples Control You – from last year’s article. The pre-programmed ID NIMBUS Presto reigns in sample chaos by enabling users to combine separate workflows on the same instrument. The system also allows a variety of non-proprietary labware to be used, so you can use whatever combination of input and output tubes and plates that is right for you, allowing you to concentrate on the issues that really matter – tackling backlog and turnaround time.

Think Confidence

We also previously noted that (Deck) Real Estate is King, and so ID NIMBUS Presto, based on the Microlab NIMBUS automated liquid handler, makes best use of the deck space to drive walkaway efficiency. This includes integrating a barcode reader to eliminate transcription errors and facilitate a complete chain of custody, and exclusive Compressed O-Ring Expansion (CO-RE®) technology that enables exceptional pipetting accuracy and precision, and also permits enhanced functionality such as the use of on-deck gripper paddles that transport samples around the deck.

Time savers such as rapid assay formats, flexibility, and batched samples of up to 96 samples per run really add up. Paperwork is also streamlined. Hooking up to your lab’s LIMS to create worklists and store results –and tracking all robotic actions associated with a sample and analyst for output as a standardized document in a case file – help to put time back on the analyst’s clock.

Speaking of the analyst’s valuable time, the big benefit of an automated workflow is regaining time that you used to spend on low value activities like pipetting. This time can now be applied elsewhere. Think of what you can accomplish with this newly found freedom. You could take a small break, perhaps grabbing coffee or fresh air to recharge your brain, or you could forge ahead with high value activities like data interpretation. The choice is yours. Either way, through automation, the overall lab can accomplish much more in a day, week, or month compared to manual methods.

Let’s not forget about the quality angle here, because speed, throughput, and time are meaningless if the results aren’t truly reflective of the sample. Hamilton and Thermo Fisher Scientific internally validated the ID NIMBUS Presto based on the Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines. We fully evaluated the performance of the ID NIMBUS Presto so that you can have confidence in system performance right out of the box.

The accuracy of the automated assay using either PrepFiler or PrepFiler BTA chemistry, for example, confirmed that generated reference standard profiles were 100% concordant to expected results, while sensitivity studies confirmed that DNA yield was proportional to sample input. Replicate sample dilutions and concentrations processed over multiple runs in respective automated workflows produced DNA concentrations well within the limits of acceptable and expected variation. And, when compared to a previously validated automated system (with lower throughput), results obtained using the ID NIMBUS Presto results were found to be equivalent or greater than that of the other system.

Finally, in case-type sample studies, we processed a whole bunch of samples typically analyzed in a forensic DNA lab, from routine reference samples to challenging teeth, and swabs from just about anything within reach. The ID NIMBUS Presto yielded results comparable again to that of a previously validated automated system.

Think About Taking the Next Step

It is possible to take small steps along your individual journey to an automated ecosystem. An automated ecosystem with an assay ready workstation that is not only compatible but pre-programmed for use with multiple assay kits. One that can process a wide variety and quantity of forensic DNA samples, put time back on analyst clocks, provide economies of scale and size…all without sacrificing budgets or quality.