Self-assembling filter can remove fluoride

Fluoride is the stuff in toothpaste that helps strengthen teeth, and in some parts of the UK and elsewhere, we add fluoride to drinking water for this purpose. But if there’s too much fluoride in the water, which affects people in at least 25 highly populated countries around the world - it softens bones, and children become susceptible to bone deformities. Unfortunately, it’s very difficult and expensive to remove the offending dissolved fluoride “ions” from the water. But researchers at Tufts University have been inspired by nature; they’ve been looking at the pores that our cells carry on their membranes to selectively allow some ions through but not others. By using polymers to build something approximating one of these pores or “ion channels”, they’ve produced a membrane that can filter out fluoride, as Sally Le Page heard from Ayse Asatekin...