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Accurate detection of hydrogen peroxide (H 2 O 2) is crucial in health, food and environmental monitoring. In this research, 3D nanostructured indium tin oxide (ITO) electrodes, prepared by the glancing angle deposition technique, were coated with a thin layer of platinum via atomic layer deposition (ALD), and the novel core/shell structure was used for electrochemical detection of H 2 O 2. X-ray diffraction analysis confirmed the presence of crystalline Pt, and morphological assessments via scanning electron microscopy and energy dispersive x-ray spectroscopy revealed conformal deposition of Pt across the micron long ITO columns. The electrode prepared under optimized ALD conditions exhibited two contiguous ranges of linear H 2 O 2 sensitivity: a low concentration range from 1 to 10 μM H 2 O 2 with an outstanding sensitivity of 5400 ± 260 μA mM−1 cm−2 leading to a 0.9 µM limit of detection, and a higher concentration linear range from 10 μM to 8 mM H 2 O 2 with 330 μA mM−1 cm−2 sensitivity. The sensor was selective to H 2 O 2 in the presence of potential interferents found in local drinking water, and it maintained consistent sensing performance over a prolonged period of 50 days with a relative standard deviation of 3.5 %. This promising performance underscores the effectiveness of the deposition techniques employed in this study. [Display omitted] • High surface area ITO/Pt core/shell electrodes are formed by glancing angle deposition and atomic layer deposition. • Conformal Pt coating is confirmed by x-ray diffraction and energy-dispersive x-ray spectroscopy compositional mapping. • High performance H 2 O 2 sensing is demonstrated, with low detection limit, high sensitivity and wide linear ranges. [ABSTRACT FROM AUTHOR]

We herein describe a novel lateral flow assay (LFA) to detect H 2 O 2 by utilizing self-biotinylation of G-quadruplex (G4). In this strategy, the G4 strand promotes the self-biotinylation of G4 itself in the presence of H 2 O 2 , which is then allowed to bind to the FAM-labeled complementary detector probe. The resulting biotin-labeled G4/FAM-detector probe complex is captured on the test line, producing a red-colored band during lateral flow readout. Based on this unique approach, we achieved the naked-eye detection of target H 2 O 2 at concentrations as low as 1 μM, with reliable quantification down to 0.388 μM. This method also demonstrated exceptional specificity in distinguishing H 2 O 2 from other non-target molecules. We further verified its versatile applicability by reliably identifying another biomolecule, choline, by coupling with choline oxidase, which generates H₂O₂ during oxidation. This novel LFA strategy holds great promise as a powerful point-of-care testing (POCT) platform for detecting a large spectrum of target biomolecules by employing their corresponding oxidases. [ABSTRACT FROM AUTHOR]