Bioinspired Cu-based metal-organic framework mimicking SOD for superoxide anion sensing and scavenging

Superoxide anion (O2 & BULL;-) is typically produced in living cells and organisms, while excess O2 & BULL;- may cause unexpected damage, so monitoring and scavenging the O2 & BULL;- is of considerable significance to exploring physiological and pathological process. In this study, a Cu-based metal-organic framework (Cu-MOF) which comprise sequential Cu metal ion and conductive organic 2,5-dicarboxylic acid-3,4-ethylene dioxythiophene is synthesized to mimic superoxide dismutase (SOD), in which Cu is the essence of active site. On one hand, the Cu-MOF possesses excellent electrocatalytic activity to detect O2 & BULL;- at -0.05 V, biased at which potential the electrode showed good linearity toward O2 & BULL;- with detection limit of 0.283 & mu;M and interference immunity for AA, DA, UA, 5HT and H2O2. The Cu-MOF modified microelectrode was applied for measuring the O2 & BULL;- released from living cells real time and monitoring O2 & BULL;- generation in rat brain. On the other hand, this Cu-MOF has the catalytic activity to mimic the superoxide dismutase for scavenging O2 & BULL;- in HeLa cells effectively. This work provides a methodology to design metal ion based enzyme mimetic for analyzing and scavenging O2 & BULL;- in cells and in vivo.