A nano sized machine which can enter living cell

Using polymer-coated gold nanoparticles, researchers at University of Cambridge and University of Bath developed a nanoscale sized engine that can even enter living cells to fight disease. How does this function? Below is the explanation given in the release from the University of Bath: "The prototype device is made using tiny charged particles of gold, bound together with temperature-responsive polymers in the form of a gel. When the ‘nano-engine’ is heated to a certain temperature with a laser, it stores large amounts of elastic energy in a fraction of a second, as the polymer coatings expel all the water from the gel and collapse. This has the effect of forcing the gold nanoparticles to bind together into tight clusters. But when the device is cooled, the polymers take on water and expand, and the gold nanoparticles are strongly and quickly pushed apart, like a spring." The results of this research are reported in the journal PNAS. Expanding polymer-coated gold nanoparticles, Yi Ju University of Cambridge. “We know that light can heat up water to power steam engines,” said study co-author Dr Ventsislav Valev, from the University of Bath’s Department of Physics. “But now we can use light to build a piston for engines at the nanoscale.” “It’s like an explosion,” said Dr Tao Ding from Cambridge’s Cavendish Laboratory, and the paper’s first author. “We have hundr...