Electrochemical biosensors based on multifunctional double-enriched MOFs@MOFs derivatives for the detection of malathion

Multifunctional nanocomposites derived from metallic-organic frameworks @ metallic-organic frameworks (MOFs@MOFs) based on nanoarchitectonics may provide an innovative approach for the design of promising biosensors. A novel electrochemical biosensor based on tribulus-shaped ZrO2@Fe2O3-C nanocomposites for ultrasensitive determination of organophosphorus pesticides (OPs) was prepared the pyrolysis of UiO-66@MIL-88B. ZrO2 from the inner UiO-66 displayed an ultrahigh adsorption capability for OPs, and the interface electronic interaction of ZrO2@Fe2O3 made Fe2O3 positive, which can fix and enrich acetylcholinesterase (AChE) in the outer layer, since AChE was a negatively-charged enzyme. The dual enrichment property and synergistic effect of ZrO2@Fe2O3-C were responsible for enhanced detection performances toward OPs, including a wide linear range (3.07 x 10-14 M-3.07 x 10-8 M) and a low limit of detection (3.9 x 10-15 M) (S/N = 3). The emergence of the multifunctional nanocomposites, through calcining MOFs@MOFs, opens a new chapter for the construction of biosensors for OPs determination.