Synchronous detection of glutathione/hydrogen peroxide for monitoring redox status in vivo with a ratiometric upconverting nanoprobe

Cellular redox status presents broad implications with diverse physiological and pathological processes. Simultaneous detection of both the oxidative and reductive species of redox couples, especially the most representative pair glutathione/hydrogen peroxide (GSH/H₂O₂), is crucial to accurately map the cellular redox status. However, it still remains challenging to synchronously detect GSH/H₂O₂ in vivo due to lack of a reliable measuring tool. Herein, a ratiometric nanoprobe (UCNP-TB) possessing simultaneous delectability of GSH/H₂O₂ is established based on a multi-spectral upconverting nanophosphor (UCNP-OA) as the luminescence resonance energy transfer (LRET) donor and two dye molecules as the acceptors, including a GSH-sensitive dye (TCG) and a H₂O₂-sensitive dye (BCH). With the as-prepared UCNP-TB, real-time and synchronous monitoring the variation of GSH and H₂O₂ in vitro and in living mice can be achieved using the ratio of the upconversion luminescence (UCL) at 540 and 650 nm to that at 800 nm as the detection signal, respectively, providing highly inherent reliability of the sensing results by self-calibration. Moreover, the nanoprobe is capable of mapping the redox status within the drug-resistant tumor and the drug-induced hepatotoxic liver via ratiometric UCL imaging. Thus, this nanoprobe would provide a reliable tool to elucidate the redox state in vivo.