ABSTRACT
Ag+ ions have been developed.9-11 However, there are only a few successful examples of molecular probes for Ag+ ion detection.12,13
Compared with the above methods, colorimetric detection is a simple, fast, and efficient method for determining targets with the aid of obvious color change, due to their naked-eye applications free of expensive equipment.14 Plasmonic nanoparticlebased colorimetric detection including using gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs), has drawn increasing attention due to their high extinction coefficients and the distancedependent optical properties.15,16 When AuNPs or AgNPs aggregate, a visual color change as well as UV-vis spectral change would be observed, due to the unique optical properties provided by Surface Plasmon Resonance (SPR). Therefore, due to the sensitive and obvious red-to-blue or yellow-to-brown color change, AuNPs or AgNPs is an important colorimetric platform and AuNP/ AgNPs-based colorimetric assays have been successfully designed and widely applied for detecting metal ions/anions17 small molecules,18 proteins,19 enzyme activity,20 and DNA,21 depending on surface chemistry-based functionalization and following tailorable optical changes.
