Accurate In Situ Monitoring of Mitochondrial H2O2 by Robust SERS Nanoprobes with a Au–Se Interface

Mitochondrial redox homeostasis plays a vital role in many biological processes. Hydrogen peroxide (H 2 O 2 ), one of the most important components for the balance between oxidizing species and reducing species, also acts as the messenger of mitochondrial damage. Thus, an accurate in situ quantitative detection of H 2 O 2 in mitochondria is very important for the evaluation of mitochondrial redox homeostasis. Here, we develop robust surface-enhanced Raman spectroscopy (SERS) nanoprobes based on Au nanoparticles as SERS substrate and functionalized carrier, which is further modified with a phenylboronic acid pinacol ester for specific H 2 O 2 response and a location peptides for mitochondrial targeting by creating a robust Au–Se interface. The SERS nanoprobes show good resistance to abundant thiol under biological conditions and superior performance for mitochondria H 2 O 2 monitoring in living cells than the SERS nanoprobes with the traditional Au–S interface, which enables us to achieve in situ quantification of mitochondrial H 2 O 2 and obtain its real-time dynamic change under oxidative stress.