Luminescent SiO2@Tb/guanosine 5'-monophosphate core-shell nanoscale coordination polymers for superoxide anion detection.

It is of great significance for superoxide anion (O2•-) detection due to its important role in regulation of biological function. The nanoscale coordination polymers (NCPs) core-shell nanostructures have attracted increasing interests for their nanosized-dependent properties. In this study, SiO2@Tb/guanosine 5'-monophosphate (GMP) NCPs with core-shell nanostructures was designed for O2•- detection. The SiO2@Tb/GMP NCPs core-shell nanostructures were produced by using SiO2 nanoparticles (NPs) as template to control their nano-size. First, Tb3+ was adsorbed on the surface of SiO2NPs by coordination with -COOH of SiO2NPs. Then the Tb/GMP NCPs shells were grown along the surface of SiO2NPs. The SiO2@Tb/GMP NCPs core-shell nanostructures were characterized with scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and Zeta potential. The resulted SiO2@Tb/GMP NCPs core-shell nanostructures displayed strong Tb/GMP emission which decreased linearly with the increased O2•- concentration in the range from 5.3 nM to 6.0 μM with a limit detection of 2.18 nM. And the SiO2@Tb/GMP NCPs core-shell nanostructures also exhibited good selectivity and high sensitivity in HEPES buffer at pH 7.4.