ac4001942_si_001.pdf (231 kB)
Inhibition of dsDNA-Templated Copper Nanoparticles by Pyrophosphate as a Label-Free Fluorescent Strategy for Alkaline Phosphatase Assay
journal contribution
posted on 2013-04-16, 00:00 authored by Liangliang Zhang, Jingjin Zhao, Min Duan, Hua Zhang, Jianhui Jiang, Ruqin YuOn
the basis of the inhibition of double strand DNA (dsDNA)-templated
fluorescent copper nanoparticles (CuNPs) by pyrophosphate (PPi), a
novel label-free turn-on fluorescent strategy to detect alkaline phosphatase
(ALP) under physiological conditions has been developed. This method
relies on the strong interaction between PPi and Cu2+,
which would hamper the effective formation of fluorescent CuNPs, leading
to low fluorescence intensity. The ALP-catalyzed PPi hydrolysis would
disable the complexation between Cu2+ and PPi, facilitating
the formation of fluorescent CuNPs through the reduction by ascorbate
in the presence of dsDNA templates. Thus, the fluorescence intensity
was recovered, and the fluorescence enhancement was related to the
concentration of ALP. This method is cost-effective and convenient
without any labels or complicated operations. The present strategy
exhibits a high sensitivity and the turn-on mode provides a high selectivity
for the ALP assay. Additionally, the inhibition effect of phosphate
on the ALP activity was also studied. The proposed method using a
PPi substrate may hold a potential application in diagnosis of ALP-related
diseases or evaluation of ALP functions in biological systems.