ZnO nanowire-based fluorometric enzymatic assays for lactate and cholesterol

• Published in: Mikrochimica acta (1966) Vol. 187; no. 3; p. 180
• Main Authors: Briones, María, Busó-Rogero, Carlos, Catalán-Gómez, Sergio, García-Mendiola, Tania, Pariente, Félix, Redondo-Cubero, Andrés, Lorenzo, María Encarnación
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.03.2020; Springer
• Subjects: Analytical Chemistry; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Cholesterol; Hydrogen peroxide; IX NyNA 2019. International Congress on Analytical Nanoscience and Nanotechnology; Lactates; Microengineering; Nanochemistry; Nanotechnology; Original Paper; Oxidases; Type 2 diabetes; Zinc oxide; Lactate oxidase; Indirect optical method; Hydrogen peroxide; ZnO NWs-enzyme bioconjugate; Photoluminescence; Fluorescence; Cholesterol oxidase; Collisional quenching mechanism; Human serum sample; Enzymatic reaction
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-020-4137-7

A rapid fluorometric method is described for the determination of lactate and cholesterol by using ZnO nanowires (ZnO NWs). The assay is based on the detection of the hydrogen peroxide generated during the enzymatic reactions of the oxidation of lactate or cholesterol. Taking advantage of the electrostatic interactions between the enzymes and the ZnO NWs, two bioconjugates were prepared by mixing the nanomaterial and the enzymes, viz. lactate oxidase (LOx) or cholesterol oxidase (ChOx). The enzymatically generated hydrogen peroxide quenches the fluorescence of the ZnO NWs, which have emission peaks at 384 nm and at 520 nm under 330 nm photoexcitation. H 2 O 2 quenches the 520 nm band more strongly. Response is linear up to 1.9 μM lactate concentration, and up to 1.1 μM cholesterol concentration. Relative standard deviation was found to be 5%. The detection limits for lactate and cholesterol are 0.54 and 0.24 μM, respectively. Graphical abstract Schematic representation of fluorescence assay based on ZnO nanowires photoluminiscence for lactate and colesterol detection