Langmuir, Vol.28, No.1, 883-888, 2012
Control of Metal-Enhanced Fluorescence with pH- and Thermoresponsive Hybrid Microgels
In this paper, we report on the Ag nanopartide-containing hybrid poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-co-PAA) microgels with pH- and thermoresponsive metal-enhanced fluorescence (MEF). The hybrid microgels were prepared by in situ reducing Ag salts to Ag nanopartides in the PNIPAM-co-PAA microgels. According to the interaction distance-dependent nature of MEF effects, we can realize a controllable MEF effect by adjusting the average interaction distance between fluorophores and Ag nanoparticles due to the good stimuliresponsive swelling-shrinking behavior of the hybrid microgels. The results show that MEF effect can be well tuned in the pH region 2-12 as well as the temperature region of 20-50 degrees C. By this method, an enhanced fluorescence detection can possibly be manipulated by adjusting external stimuli such as pH and temperature.