Wilhelm, StefanDel Barrio Redondo, MelisaHeiland, JosefHimmelstoß, SandyGalbán, JavierWolfbeis, OttoHirsch, Thomas2024-01-152024-01-152014Stefan Wilhelm, Melisa del Barrio, Josef Heiland, Sandy F. Himmelstoß, Javier Galbán, Otto S. Wolfbeis, and Thomas Hirsch ACS Applied Materials & Interfaces 2014 6 (17), 15427-15433 DOI: 10.1021/am50386431944-824410.1021/am5038643https://hdl.handle.net/20.500.14352/93066We report on upconverting luminescent nanoparticles (UCLNPs) that are spectrally tuned such that their emission matches the absorption bands of the two most important species associated with enzymatic redox reactions. The core-shell UCLNPs consist of a β-NaYF4core doped with Yb3+/Tm3+ions and a shell of pure β-NaYF4. Upon 980 nm excitation, they display emission bands peaking at 360 and 475 nm, which is a perfect match to the absorption bands of the enzyme cosubstrate NADH and the coenzyme FAD, respectively. By exploiting these spectral overlaps, we have designed fluorescent detection schemes for NADH and FAD that are based on the modulation of the emission intensities of UCLNPs by FAD and NADH via an inner filter effect.engjournal article1944-8252https://doi.org/10.1021/am5038643open access543Química analítica (Química)2301 Química Analítica