Cerium-cysteine nanozymes with dual enzyme-like activities for paper-based intelligent detection of ginkgo acid

Abstract

Ginkgo acid (GA), the primary toxic component in ginkgo products, presents significant safety concerns. To overcome the limitations of traditional chromatographic detection methods, this study aimed to construct a cerium-cysteine (noted as “CeCys”) nanozyme with oxidase (OXD)- and peroxidase (POD)-like activities for colorimetric detection of GA. Through the self-assembly of Ce^3 + and cysteine (Cys), CeCys was constructed. Since GA could inhibit the dual enzyme-like activities of CeCys nanozyme, the developed system could detect GA via colorimetric analysis with the limit of detection (LOD) as 0.71 μg mL⁻¹ (OXD-like activity) and 0.83 μg mL⁻¹ (POD-like activity), respectively. The system also exhibited excellent selectivity and anti-interference capabilities. Fourier transform infrared spectrum analysis revealed the binding of GA with CeCys disrupted the coordination between Ce and Cys, thereby inhibiting the active sites. By integrating the OXD-like activity and a test-paper platform with smartphone, the CeCys nanozyme-based detection system could achieve the intelligent detection of GA with a LOD of 2.78 μg mL⁻¹ and an ultrafast detection time of 2 min. Practical application in ginkgo leaf samples conformed the high accuracy with recovery rates of 94.5 %-114 %. This study might provide significant technical references and theoretical foundations for nanozyme-based rapid platforms for GA detection.