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    Water Testing - Now In A Pullulan Pill
    By News Staff | April 28th 2014 03:44 PM | 1 comment | Print | E-mail | Track Comments

    Water testing can  be a cumbersome process, with labs and delays and waiting. 

    Chemical engineers from McMaster University have reduced the sophisticated chemistry required for testing water safety to a simple pill, by adapting technology found in...a breath strip. 

    Want to know if a well is contaminated? Drop a pill in a vial of water and shake it. If the color changes, there's the answer. The development has the potential to dramatically boost access to quick and affordable testing around the world.

    The idea occurred to team member Sana Jahanshahi-Anbuhi, a PhD student in Chemical Engineering who came across the breath strips while shopping and realized the same material used in the dissolving strips could have broader applications. 

    The researchers have now created a way to store precisely measured amounts of enzymes and other active agents in pills made from the same naturally occurring substance used in breath strips, putting lab-quality science within instant and easy reach of people who need quick answers to questions such as whether their water is safe.

    "This is regular chemistry that we know works but is now in pill form," says John Brennan, director of McMaster's Biointerfaces Institute, where the work took place. "The user can be anybody in a village somewhere who can take a pill out of a bottle and drop it in water."

    The material, called pullulan, forms a solid when dry, and protects sensitive agents from oxygen and temperature changes that can render them useless within hours. Until now, such agents have had to be stored at extremely cold temperatures and shipped in vials packed in huge chunks of dry ice, at great cost and inconvenience. Using them has been awkward, bulky and often wasteful.

    "Can you modify packaging so it has a sensor to tell you if your chicken has gone off?" Brennan asks. "The reason that doesn't exist today is because there's no way you can keep these agents stable enough."

    The new method allows the same materials to be stored virtually anywhere for months inside tiny pills that dissolve readily in liquid. The pills are inexpensive to produce and anyone can add them to well water, for an instant reading of pesticides,
    e. coli or metals, for example.

    The new technology can easily be scaled up and find its way to market quickly, says Brennan. Pullulan is already approved for wide commercial use and is mass produced, which can speed the journey to market.



     Published in Angewandte Chemie. Source: McMaster University


    Comments

    rholley
    When I was a lad reading pre-war biology books, I frequently sometimes came across the word pullulate.  Here are three of the shades of meaning given by the Oxford English Dictionary:
    • To be developed or produced as offspring; to spring up abundantly, multiply.
    • To teem, swarm. Freq. with with.
    • Of a cell or animal, esp. a pathogenic organism: to breed, multiply; to reproduce prolifically.
    So what is it doing in the name of a biopolymer?  Pullulan (formula below)  is a polysaccharide produced by the fungus Aureobasidium pullulans — the name suggesting that there’s a lot of it about: an impression confirmed by Wikipedia, which says it is
    a ubiquitous black, yeast-like fungus that can be found in different environments (e.g. soil, water, air and limestone).
    Before even looking, the -an suffix, rather like the ending of a Latin word, is a strong hint to a chemist like myself that this is a polysaccharide.

    The name of the fungus itself contains a puzzle.  It belongs to one of the two largest divisions of the Fungi, the Ascomycota, rather than, as its name would seem to suggest, the Basidiomycota.  But that would take a proper fungus expert to explain.
    Robert H. Olley / Quondam Physics Department / University of Reading / England