Temperature-activated nucleic acid nanostructures.

DNA and poly(N-isopropylacrylamide) are co-assembled onto gold nanoparticles. The DNA sequences can be reversibly exposed or hidden from the polymer surface in response to temperature cues, thereby translating the temperature trigger to the on-off switching of the surface chemistry and function. When exposed by heating (∼30 °C), the DNA rapidly hybridizes to complementary strands, and chain-end biotin groups become readily accessible, while at lower temperatures these activities are largely blocked.