Metalloporphyrinic
frameworks have demonstrated to be an alternative
candidate for natural enzymes due to their diverse structures and
unique peroxidase-mimicking properties. In this study, a manganese–metalloporphyrin
framework (PCN-222(Mn)) was synthesized as a biomimetic metal–organic
framework (MOF). This catalyst exhibited highly intrinsic peroxidase-like
activity with 3,3′,5,5′-tetramethylbenzidine as the
chromogenic substrate. Additionally, a higher peroxidase-like activity
was observed in a wider pH range (from 3.0 to 8.0), which is undoubtedly
advantageous for PCN-222(Mn) to detect H2O2 under
physiological and pathological environments. Based on the excellent
peroxidase-mimicking activities of PCN-222(Mn), a novel hydrogen peroxide
(H2O2) nonenzymic amperometric biosensor was
constructed through electro-polymerizing a conductive and stable poly-glutamic
acid (PGA) film on the surface of a PCN-222(Mn)-modified electrode
(PGA/PCN-222(Mn)/GCE). Resulting from the synergistic activity of
PCN-222(Mn) and PGA film, a sensitive, selective, and reliable method
was established for H2O2 detection with a linear
range of 5 × 10–7 to 1.01 × 10–3 mol/L and detection limit of 3.1 × 10–8 mol/L.
In addition, PGA/PCN-222(Mn) has a long-term stability and can be
used over 90 cycles without any decrease in analytical performance.
These outstanding performances of the developed approach in sensitive
and selective determination of H2O2 from human
serum provides effective proof for its potential application in monitoring
low-abundance H2O2 from complicated biological
samples. This research not only expands the electrochemical applications
of metalloporphyrin frameworks but also demonstrates a promising strategy
for increasing the conductivity and stability of MOF-based electrode
materials.