Development of a rechargeable optical hydrogen peroxide sensor – sensor design and biological application

Abstract

Hydrogen peroxide (H₂O₂) is an important member of the reactive oxygen species (ROS) family. Among ROS, H₂O₂ is considered the most long-lived and can accumulate inside and outside of cells, where it is involved in both vital (signaling) and deadly (toxic) reactions depending on its concentration. Quantifying H₂O₂ within biological samples is challenging and often not possible. Here we present a quasi-reversible fiber-optic sensor capable of measuring H₂O₂ concentrations ranging from 1–100 μM within different biological samples. Based on a Prussian blue/white redox cycle and a simple sensor recharging and readout strategy, H₂O₂ can be measured with high spatial (∼500 μm) and temporal (∼30 s) resolution. The sensor has a broad applicability both in complex environmental and biomedical systems, as demonstrated by (i) H₂O₂ concentration profile measurements in natural photosynthetic biofilms under light stress reaching H₂O₂ concentrations as high as 15 μM, and (ii) the quantification of the transient increase of the extracellular concentration of H₂O₂ during stimulation of neutrophils.