Thermosensitive gold nanoparticles

Thermosensitive gold nanoparticles were fabricated by conjugating Au with a thiol-terminated poly(N-isopropylacrylamide) or PPA; this polymer stabilizer exhibits a temperature transition while undergoing a hydrophilic to hydrophobic transformation. The introduction of PPA onto gold nanoparticles has sensitized Au nanoparticles with unique temperature dependence. At low temperature (25 °C), the solutions containing PPA-functionalized gold nanoparticles are transparent, whereas higher temperatures (30 °C) lead to opaque suspensions. The thermosensitive property of PPA-functionalized Au nanoparticles is reversible, and the clear?opaque suspensions can be repeated many times. Copyright © 2004 American Chemical Society.