Au NPs-Induced ligand-defective Ce MOF boosting oxidase-like activity for colorimetric aptasensor platform...

In this study, Au NPs were substituted for a H₂BDC ligand on the Ce MOF, resulting in ligand-defective Au@Ce MOF. The coordination environment of the cerium metal sites is effectively disrupted, leading to the formation of electron-enriched Au-O-Ce interface. It results in reduction of the electron density on the Ce MOF surface and lowering of the oxygen adsorption energy barrier. Additionally, more Ce³⁺/Ce⁴⁺ active sites are exposed, endowing it with exceptional oxidase (OXD)-like activity (Km, 0.045 mM; Vmax, 1.13 × 10^-7 M/s). Base on this, ultrasensitive colorimetric aptasensor and lateral flow assay (LFA) were developed utilizing competitive target binding, enabling detection of deoxynivalenol (DON). Under optimized conditions, the colorimetric aptasensor and LFA exhibited linear ranges of 0.5-65 ng/mL and 1-5000 ng/mL, with low LODs determined as 0.449 ng/mL and 0.783 ng/mL, respectively. This study presents novel approach for the point-of-use and sensitive detection of food contaminants using Apt-LFA based on nanoenzymes.