Development of Sensing Functions of Gold Nanoparticles Conjugated with Thermoresponsive Polymers

Concerning the development of sensing functions of gold nanoparticles were discussed based on conjugation with thermoresponsive polymers. The combination of thermoresponsive polymers and gold nanoparticles enabled us to develop not only their inherent functions, but also new functions that would produce novel analytical systems. Aggregated ca. 13 nm gold nanoparticles conjugated with thermoresponsive polymers were disassembled by thermal stimuli, heating followed by cooling, resulting in a change in the solution color from bluepurple to red. Based on the unique phenomenon, novel analytical methods were developed. On the other hand, gold nanoparticles smaller than ca. 2 nm, referred to gold nanoclusters, exhibited other fascinating behavior. When conjugated with thermoresponsive polymers and heated, the gold nanoclusters grew spontaneously, revealing a reddish color. In addition, when conjugated with sulfhydryl peptides, the gold nanoclusters became fluorescent showing a fluorescence band in the near infra-red region. © 2019. All Rights Reserved.