Layer-by-layer growth of molecular-sieving ZIF-8 thin film on AuPt nanoparticles for highly selective electrochemical detection of H2O2 in cancer cells

Abstract

The development of highly selective enzyme-free electrochemical sensors remains challenging, particularly in complex biological environments containing multiple electroactive interferents. To address this issue, we present a hierarchical sensing interface by innovatively growing a zeolitic imidazolate framework-8 (ZIF-8) film on three-dimensional AuPt nanoalloys. This design capitalizes on the molecular sieving effect of ZIF-8, which allows selective permeation of H2O2 to the underlying catalytic AuPt surface while effectively blocking larger interferents such as ascorbic acid, uric acid, and dopamine. The resulting sensor exhibits exceptional selectivity, enabling accurate detection of H2O2 even in the presence of interferents at concentrations 20-fold higher. Moreover, through the controllable growth of the ZIF-8 film and the high catalytic activity of the AuPt nanoalloy, the optimized sensor also demonstrates high sensitivity, a wide linear range, and a low detection limit. It was also successfully applied to in situ tracking of H2O2 release from live cervical and breast cancer cells. This work provides a novel strategy for constructing metal-organic framework-based heterostructures for highly selective sensing, paving the way for reliable H2O2 monitoring in biomedical applications.