Artificial nanozyme based on platinum nanoparticles anchored metal-organic frameworks with enhanced electrocatalytic activity for detection of telomeres activity

This study reports a new artificial nanozyme based on ultra-small Pt nanoparticles (Pt NPs) grown on nanoscale metalloporphyrin metal organic frameworks (P-MOF(Fe)) (termed as Pt@P-MOF(Fe)) as biomimetic catalysts and redox mediator to detect the telomerase activity. In this system, the P-MOF(Fe) were used as nanocarrier and signal media. The DNA functionalized Pt@P-MOF(Fe) was as signal probe and exhibited enhanced electrochemical signal in the presence of H2O2, owing to the synergistic effect between P-MOF(Fe) and Pt NPs. Upon the addition cell extract, the telomerase primer could extend and then hybridize with assistant DNA2 in the triple-helix, leading to the structure of triple-helix changes and release the hairpin DNA to hybridize with the capture DNA on the surface of Pt@P-MOF(Fe), resulting in the electrochemical signal readout of H2O2 reduction. With the aid of recycling amplification of Exonuclease III, the telomeres sensor exhibited the detection down to 20 Hela cell mL−1. This work supplies a new avenue to design artificial enzyme catalysts and serves as an ideal platform to use metalloporphyrin metal organic frameworks as signal media for detection of analytes. •Porphyrinic metal-organic framework (MOFs) is designed as nanocarrier and electrochemical probe.•Pt NPs grown on the surface of MOFs could maintain high stability and catalytic activity.•The synergy between Pt NPs and MOFs enhances the high electrocatalytic activity of Pt@P-MOF(Fe) and electrochemical signal.•The signal was amplified by triple-helix molecular switch and Exonuclease III.•The telomerase activity sensor showed good performance.