Ratiometric Hydrogen Peroxide Biosensing with Enzyme-Mimetic Luminescent Nanoparticles

Hydrogen peroxide (H₂O₂) is an important (bio)molecule in a variety of bioprocesses and is often decomposed in vivo using the enzyme catalase. Growing interest in quantification of H₂O₂ exists particularly in pharmaceutical and biological applications, since it is not only a potential biomarker for inflammations and infections, but also an intermediate molecule in enzyme-based assays such as the plasmonic ELISA. However, a label-free, and calibration-free assay has yet to be developed. In this work, we propose a nanoparticle-based ratiometric optical biosensor to detect H₂O₂ in physiological relevant solutions. For this goal, we combine luminescent enzyme-mimetic CeO₂:Eu³⁺ nanoparticles with optically stable Y₂O₃:Tb³⁺ nanophosphors [1,2] that serve as concentration independent reference value. Both nanoparticles are synthesized simultaneously in the same single step process, allowing for a highly scalable and reproducible production as well as facilitating direct deposition of this material on glass substrates for the single step fabrication of H₂O₂ biosensing surfaces. It is shown, that the luminescence properties of the CeO₂:Eu³⁺ nanoparticles vary dramatically for different concentrations of H₂O₂, allowing for sub-µM limit of detections while the Y₂O₃:Tb³⁺ phosphors are highly utilizable as reference material. Hence, the presented material can be used for selective, label-free H₂O₂ sensing as well as be synthesized in a highly scalable fashion.

[1] Sotiriou, G.A., Schneider, M., & Pratsinis, S.E. (2011) J. Phys. Chem. C 115, 1084-1089.

[2] Sotiriou, G.A., Franco, D., Poulikakos, D., & Ferrari, A. (2012) ACS Nano 6, 3888-3897.