Biodegradable plaster

Whether you bravely rip it off in one or gingerly peel it back inch by inch, removing a plaster from a wound can make even the toughest of cookies wince.
But the painful experience could soon be a thing of the  past – thanks to a plaster made out of starch.
The plasters, developed by US researchers, are biodegradable and so never need to be removed.
Instead they gradually break down and turn into glucose, which the body can absorb safely.
The same process could also be used to make cheaper and more environmentally friendly toilet paper and napkins.
Scientists at Penn State University have worked out how to spin starch into fine strands, which can then be combined into paper-like mats.
Once the process is scaled to industrial size, companies could make bandages and other medical dressings using starch fibres.
Co-author Lingyan Kong, a food science graduate, said: 'There are many applications for starch fibres.
'Starch is the most abundant and also the least expensive of natural polymers.
'Starch is easily biodegradable, so bandages made from it would, over time, be absorbed by the body. So, you wouldn't have to remove them.'
Starch doesn't completely dissolve in water, instead becoming a kind of gel which is too thick to turn into fibres.
To solve the problem, the researchers added a solvent to help dissolve the starch, without destroying its molecular structure.
They then used an electrospinning device to stretch the starch solution into fibres.
The researchers, supported by the U.S. Department of Agriculture, have filed a patent on their breakthrough.