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Odor issues occurring in drinking water have been a big challenge to face for water suppliers globally, which highly commend to develop quick or on-site odor detection tools for the management of odor problems. Olfactory sensors based on odor-binding proteins (OBPs) have been utilized to analyze pollutants in food and air samples, while their application for the detection of typical odor-causing compounds in drinking water is rarely reported, partly due to the lack of knowledge about the binding properties of odorants. In this study, the binding affinity and mechanism of human odor-binding protein OBP2a to 14 typical odorants in water were first assessed using fluorescent competitive binding assays and molecular docking techniques. The 14 odorants include 7 aldehydes, 2 terpenes, 2 thioethers, bis(2-chloro-1-methylethyl) ether (DCIP), 2-ethyl-4-methyl-1,3-dioxolane (2E4MDL), and 2-isobutyl-3-methoxypyrazine (IBMP). The results showed that OBP2a could bind to 9 odorants (Ki = 29.91 μmol/L–48.36 μmol/L), including IBMP, 2-MIB, and six aldehydes (hexanal, heptanal, benzaldehyde, 2-octenal, decanal, and β-cyclocitral), among which stronger binding affinity for aldehydes is observed (Ki = 29.91 μmol/L–43.87 μmol/L). Molecular docking confirmed that Lys112 and Phe97 are major amino acid residues involved in the binding of the most target odorants. To be specific, IBMP and aldehydes can form hydrogen bonds with Lys112; aromatic ring-containing odorants such as IBMP and benzaldehyde can also form pi–pi stacking with Phe97. The binding affinity of OBP2a to fatty aldehydes including hexanal, heptanal, 2-octenal, decanal, and β-cyclocitral increased with the increase of hydrophobicity of aldehydes. The valuable information to the binding of OBP2a to typical odorants in this study would provide a theoretical foundation for the development of OBP-based odor detection biosensors to achieve quick detection in drinking water, further helping the improvement of water treatment processes in the water industry.HighlightsOBP2a has a broad binding spectrum and binds preferentially to aldehydesLys112 and Phe97 are main amino acid residues involved in binding of 14 odorantsHydrogen bond contributes to the compact binding of OBP2a and aldehydesHydrophobicity of aldehydes affects significantly their binding affinity to OBP2a

The inadequate generation of reactive oxygen species (ROS) and metastasis of malignant tumors are critical factors that limit the efficacy of conventional sonodynamic therapy in cancer treatment. Herein, an engineered piezocatalyst: cholesterol oxidase (CHO)‐loaded Pt‐ZnO nanoparticles (Pt‐ZnO/CHO) that can explosively generate large amounts of ROS and block the metastasis of tumor, is developed for improving piezocatalytic tumor therapy. In this process, Pt‐ZnO can substantially generate ROS via initiating ultrasound (US)‐triggered piezocatalytic reactions. In situ‐grown Pt nanoparticles not only optimize piezocatalytic activities but also facilitate oxygen (O2) production, thereby synergistically boosting ROS generation. Moreover, O2 produced by Pt‐ZnO can accelerate the depletion of excess cholesterol in tumor cells under CHO catalysis to disrupt the integrity of lipid rafts and inhibit the formation of lamellipodia, significantly suppressing the proliferation and metastasis of tumor cells. This strategy by promoting ROS generation and blocking the metastatic pathway of cancer cells offers a new idea for enhanced efficacy‐oriented cancer therapeutic strategies. Under ultrasound (US) irradiation, cholesterol oxidase (CHO)‐loaded Pt‐ZnO nanoparticles (Pt‐ZnO/CHO) initiates a piezo‐catalytic cascade reaction that produces oxygen (O2) and reactive oxygen species (ROS), leading to the consumption of cholesterol, disruption of lipid raft integrity, and interference with lamellipodia formation. This process inhibits epithelial‐mesenchymal transition (EMT), suppressing tumor migration and invasion, and achieving an effective piezo‐catalytic anticancer effect.