Highly sensitive and selective detection of silver(I) ion using nano-C-60 as an effective fluorescent sensing platform

In this Communication, we report water-soluble nano-C-60 in the first use as an effective fluorescent sensing platform for the highly sensitive and selective detection of Ag+. The general concept used in this approach is based on a fluorescently labeled single-stranded DNA (ssDNA) probe that adsorbs on nano-C-60, leading to substantial dye fluorescence quenching; however, in the presence of Ag+, C-Ag+-C coordination induces the probe to fold into a hairpin structure, which does not adsorb on nano-C-60 and thus retains the dye fluorescence. This sensing system exhibits a detection limit as low as 1 nM and has a high selectivity against other metal ions. Finally and most importantly, we demonstrate its performance in real sample analysis.