Co-catalytic Fc/HGQs/FeO nanocomposite mediated enzyme-free electrochemical biosensor for ultrasensitive detection of MicroRNA.

Herein, a novel co-catalytic ferrocene/hemin/G-quadruplexes/FeO nanoparticles (Fc/HGQs/FeO) nanocomposite was synthesized to significantly magnify the electrochemical signal of ferrocene (Fc) using the synergistic catalysis of hemin/G-quadruplexes (HGQs) and FeO nanoparticles as hydrogen peroxide enzyme mimics for the construction of ultrasensitive electrochemical biosensors. The fabricated electrochemical biosensor can achieve ultrasensitive detection of miRNA-155 ranging from 0.1 fM to 1 nM, as well as a limit of detection of 74.8 aM. This strategy provides a new route to exploring efficient signal labels for signal amplification and provides an impetus to find novel methods for the construction of biosensors for biological detection and the early clinic diagnosis of diseases.