(714a) Enzyme-Mimetic Luminescent Luminescent Nanoparticles As Hydrogen Peroxide Biosensors
Here, europium-doped cerium oxide (CeO2:Eu3+) nanoparticles with well-controlled size (d = 4 â 16 nm) are prepared by flame aerosol technology and characterized in regards to H2O2 sensor response in physiologically-relevant solutions. Furthermore, we combine luminescent enzyme-mimetic CeO2:Eu3+ nanoparticles with optically stable Y2O3:Tb3+ nanophosphors [1,2] that serve as concentration-independent reference value in the same nanoaggregates. Finally, the luminescence excitation is enhanced by the addition of Bi3+ within the same crystal matrix that improves its excitation in the near-UV wavelength region.
The developed biosensors are coupled to enzyme-based assays that consume or generate H2O2 aiming the detection of other important bioanalytes, such as alcohol and glucose, using alcohol and glucose oxidase enzymes, respectively . Upon the addition of a luminescent material with no H2O2 sensitivity, ratiometric sensors can be made for the facile and fast H2O2 detection in vitro. The sensing performance of the nanoparticles was further evaluated with hydrogen peroxide producing S. pneumoniae bacteria in biological media. Furthermore, the excitation spectrum engineering by the addition of Bi3+ ions renders these materials as suitable H2O2 biosensors with conventional fluorescent microscope filter sets utilizing the near-UV excitation. The biomimetic artificial enzyme developed here could serve as a starting point of sophisticated in vitro assays towards highly sensitive detection of disease biomarkers.
 G.A. Sotiriou, M. Schneider & S.E. Pratsinis, âColor-Tunable Nanophosphors by Codoping Flame-Made Y2O3 with Tb and Euâ, J. Phys. Chem. C 115, 1084â1089 (2011).
 G.A. Sotiriou, D. Franco, D. Poulikakos, A. Ferrari, âOptically Stable Biocompatible Flame-Made SiO2-Coated Y2O3:Tb3+ Nanophosphors for Cell Imagingâ, ACS Nano 6, 3888â3897 (2012).
 A. Pratsinis, G. A. Kelesidis, S. Zuercher, F. Krumeich, S. Bolisetty, R. Mezzenga, J-C. Leroux & G. A. Sotiriou. âEnzyme-Mimetic Antioxidant Luminescent Nanoparticles for Highly Sensitive Hydrogen Peroxide Biosensingâ ACS Nano 11, 12210-12218 (2017).