Enhanced luminol electrochemiluminescence biosensing system based on highly dispersed bimetallic nanozyme coreaction accelerator and 3D DNA walker signal amplifier.

In this work, a platinum-nickel based nanozyme is prepared and used as a coreaction accelerator in the luminol-HO electrochemiluminescence (ECL) system to construct an ECL biosensor for dimethyl phthalate (DMP) detection. The PtNi/NC nanozyme possesses dispersed metal active sites, and the synergistic effect of Pt and Ni endows it with excellent catalytic performance, which effectively converts HO into more superoxide anions, and then significantly enhances the ECL intensity of the luminol system. The ECL mechanism is investigated by combining cyclic voltammetry and ECL with different types of free radical scavengers. Simultaneously, an "off-on" biosensor is constructed by integrating 3D DNA walker with enzyme-free recycling amplification for ultrasensitive detection of DMP. The biosensor based on PtNi/NC nanozyme mediated luminol-HO system and 3D DNA walker exhibits a linear range of 1 × 10 to 1 × 10 M with a detection limit of 4.3 × 10 M (S/N = 3), and displays good stability and specificity. This study demonstrates the advantages of PtNi/NC nanozyme in enhancing the luminol-HO ECL system, providing new strategy for designing efficient ECL emitter and offering a new method for detecting phthalate esters.