A fluorescence nanoplatform for the determination of hydrogen peroxide and adenosine triphosphate via tuning of the peroxidase-like activity of CuO nanoparticle decorated UiO-66.

A novel nanocomposite of CuO nanoparticle-modified Zr-MOF (CuO/UiO-66) was synthesized and developed as a fluorescence nanoplatform for H2O2 and adenosine triphosphate (ATP) via the "turn-on-off" mode in the presence of terephthalic acid (TA). The structure of CuO/UiO-66 was thoroughly characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and other techniques. The CuO/UiO-66 with enhanced peroxidase-like (POD) activity obtained due to the Zr4+ in UiO-66 is beneficial to the aggregation of CuO NPs on its surface. As a result, the strengthened fluorescence at 425 nm with the excitation of 300 nm was found due to the highly fluorescent species of TAOH. This is produced by the oxidation of TA by ·OH that came from the catalysis of H2O2 via the peroxidase mimic of CuO/UiO-66. Hence the modification of CuO NPs on porous UiO-66 can provide a friendly and sensitive physiological condition for H2O2 detection. However, upon addition of ATP, the fluorescence intensity of TAOH at 425 nm effectively declined owing to the formation of complexation of Zr4+-ATP and the interaction of CuO to ATP which hampers the catalytic reaction of CuO/UiO-66 to H2O2. The specific interaction induced "inhibition of the peroxide-like activity" endows the sensitive and selective recognition of ATP. The detection limits were 16.87 ± 0.2 nM and 0.82 ± 0.1 nM, and linear analytical ranges were 0.02-100 μM and 0.002-30 μM for H2O2 and ATP, respectively. The novel strategy was successfully applied to H2O2 and ATP determination in serum samples with recoveries of 97.2-103.8% for H2O2 and 97.6-101.7% for ATP, enriching the avenue to design functional MOFs and providing new avenue of multicomponent bioanalysis.