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Forensics paper to detect saliva

Published 11/03/2015 by Alexander Waljansson

In December, Magle visited again for a new production round of their Phadebas Forensic Press Test, a coated filter paper used in forensic investigations. We always look forward to Magle’s visits. At Innventia, we mostly deal with thinking about and developing the products and processes of the future. But in this case, we’re actually involved in the production process itself.

Around seven years ago, a Swedish medical technology company called Magle contacted Innventia, asking for help to develop a product. The product, which is now sold under the name Phadebas Forensic Press Test, is a specialist paper with a starch-coated surface that reacts when it comes into contact with saliva. As the name suggests, this is used in forensic investigations. The paper is pressed against an object that is suspected to have traces of saliva on it. If saliva is indeed present – even in very small quantities – the starch reacts and investigators can tell where to take samples for DNA analysis.

Prior to development at Innventia, the starch was sold as a powder that was dissolved at forensic laboratories and sprayed onto filter paper. The results varied significantly, depending on who carried out the test and how. Here at Innventia, we devised a continuous production method using a running web in one of our pilot facilities called LINDA. The starch-coated paper is then ready for immediate use, and the quality is extremely high and even.
When working with Magle, we can coat an entire year’s production of Phadebas Forensic Press Test with starch over the course of just a few busy days. Ahead of the production week, spraying equipment and drying cylinders are mounted onto LINDA. 

Anyone who has worked at Innventia for a few years knows straight away when a new production run is under way. The entire machine is covered in plastic and disinfected using laboratory spirit – you can almost pick up the hospital smell as you approach the production premises. Everything is cleaned thoroughly, and the floors and work surfaces are treated with an anti-bacterial agent. Of course, our labs are always clean and tidy, but when we work with Magle things have to be taken to a whole new level! For instance, we rarely wear hairnets and face masks at other times.

A production day begins with dissolving a batch of starch, which takes around 30 minutes. The solution is then held in a vessel, where it is stirred, and the vessel is connected to the spray rig. A roll of special filter paper is affixed to LINDA, the web is set rolling, the spray rig is started up and production begins. Several kilometres of paper are coated with starch during a production run, which is why an even, reliable process is so important.

Magle are always present throughout production, and we work together at every stage of the process. It’s clear that my colleagues and I are working with Magle and not just for them, which I find both enjoyable and motivating.

Alexander Waljansson
Alexander Waljansson works in the group "Process Technology" at Innventia.

Alexander Waljanson
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