Click chemistry-mediated catalytic hairpin self-assembly for amplified and sensitive fluorescence detection of Cu(2+) in human serum.

Chemically reduced Cu(2+) triggers the ligation of alkynyl- and azido-modified DNA via click chemistry. Subsequently, the ligated DNA initiates cyclic assembly of two fluorescently quenched hairpin DNAs and generates significantly amplified fluorescence signals for highly sensitive detection of Cu(2+) in human serum samples.