A fast and ultrasensitive detection of zinc ions based on "signal on" mode of electrochemiluminescence from single oxygen generated by porphyrin grafted onto palladium nanocubes.

• ZnPPIX-Pd NCs work as an ECL emitter with high ECL intensity and lower excitation potential. • The ECL was irradiated from single oxygen via electrocatalytic reduction of ZnPPIX-Pd NCs. • A fast and ultrasensitive ECL sensor was constructed for Zn2+ detection based on "signal on" mode. Zinc ions (Zn2+) act as a transcription factor in eukaryotic cells for mediating protein-protein interactions in human healthy. The simple and sensitive detection of Zn2+ is the crucial mission in analytical field. This work demonstrated a novel and fast Zn2+ detection strategy based on "signal on" mode with electrochemiluminescence (ECL) luminophore, in which singlet oxygen was generated via electrocatalytic reduction of zinc proto-porphyrin IX grafted onto Pd nanocubes (ZnPPIX-Pd NCs). In protocol, Pd NCs were synthetized under hydrothermal conditions and aminated through thermal oxidative polymerization of 3-aminopropyltriethoxysilane (APTES), followed by further linking with PPIX via amide reaction. The resulting PPIX-Pd NCs effectively captured Zn2+ in chelation and monitored by Fourier transform infrared (FTIR) spectroscopy and ultraviolet-visible (UV-vis) absorption spectroscopy. By virtue of the metal resonance responses of Pd NCs, an intense monochromic, potential shuffling and enhanced ECL irradiation shows up for the hybrid nanocomposite with H 2 O 2 as the coreactant. To this end, an ultrasensitive method based on the nanocomposite with a "signal-on" model was developed for Zn2+ detection with a low detection limit down to 0.38 nM (based on a S / N = 3), excellent precision and high stability. The ECL strategy reveals the potential application in molecular diagnosis and offers a new avenue for bioassay of structural Zn(II) proteins and zinc finger-binding nucleotides. [ABSTRACT FROM AUTHOR]