HyPer-3: A Genetically Encoded H(2)O(2) Probe with Improved Performance for Ratiometric and Fluorescence Lifetime Imaging.

High-performance sensors for reactive oxygen species are instrumental to monitor dynamic events in cells and organisms. Here, we present HyPer-3, a genetically encoded fluorescent indicator for intracellular H(2)O(2) exhibiting improved performance with respect to response time and speed. HyPer-3 has an expanded dynamic range compared to HyPer and significantly faster oxidation/reduction dynamics compared to HyPer-2. We demonstrate this performance by in vivo imaging of tissue-scale H(2)O(2) gradients in zebrafish larvae. Moreover, HyPer-3 was successfully employed for single-wavelength fluorescent lifetime imaging of H(2)O(2) levels both in vitro and in vivo.