Multi-metal nanozyme loaded (Zr/Ce) UiO-66 driven self-cascade catalysis nanoreactor based on split aptamer for sensitive detection of pathogenic bacteria

Abstract

Pathogenic bacteria pose a significant impact on human and environmental health. Therefore, establishing a rapid and sensitive method for detecting these bacteria is urgent. In this study, a self-cascade catalysis nanoreactor based on split aptamers (SPA) was developed for the sensitive detection of E. coli O157:H7, enabling a self-powered H₂O₂ strategy and improved convenience. This approach employed (Zr/Ce) UiO-66 anchored with an AuRhPt trimetallic nanozyme. The incorporation of Ce enhances the specific surface area and catalytic activity of Zr UiO-66. The AuRhPt@(Zr/Ce) UiO-66 nanozyme exhibits multiple catalytic activities, such as glucose oxidase (GOx) and peroxidase (POD) activities, enabling the development of a self-powered H₂O₂ strategy. Subsequently, the aptamer was split into two shorter fragments to minimize steric hindrance, reduce costs, and achieve high performance. A self-cascade catalysis nanoreactor was developed using a split aptamer recognition and assembly strategy for the rapid and sensitive detection of E. coli O157:H7 in different real samples. The linear range for E. coli O157:H7 was 10¹–10⁵ CFU/mL in lake water, lettuce, and milk samples, with a limit of detection (LOD) of 10¹ CFU/mL and recoveries ranging from 81% to 117%. Consequently, this self-cascade catalysis nanoreactor is well-suited to the sophisticated detection requirements of diverse samples and shows significant promise as a highly sensitive and efficient approach for identifying other targets.