28 March 2012
Scientists from China and Canada have found that a drug-loaded shape memory polymer can be manipulated by ultrasound and that they can control when and how the drugs are released.
Shape memory polymers (SMPs) can be deformed and fixed into a temporary shape and then recover their original permanent shape under external stimuli such as heat, explains lead researcher Hesheng Xia from Sichuan University, Chengdu. 'When a piece of polymer is placed in the body, it is subjected to heating at 37°C everywhere and the whole piece undergoes shape recovery,' he says. Xia and co-workers directed an ultrasound beam on a selected area of a polymer, causing a local rise in temperature and triggering shape recovery only in that area. Xia adds that ultrasound has the advantage of easily penetrating body tissue.