Dual stimulus-responsive core-satellite SERS nanoprobes for reactive oxygen species sensing during autophagy

As one kind of reactive oxygen species, hydrogen peroxide (H2O2) participated in various cellular biological processes including cell differentiation and inflammation responses. Abnormal H2O2 level is closely related to cancer and other diseases. Highly sensitive detection and monitoring H2O2 are of great importance for understanding the roles of H2O2 in cellular dynamic events. Herein, a novel dual stimulus-responsive core-satellite surface-enhanced Raman scattering (SERS) nanoprobe engineered with manganese dioxide (MnO2) and silver nanoparticles (Ag NPs) was constructed for sensitive H2O2 detection. The sensing strategy is based on the target-triggered degradation both of the “core” and “satellite”. In this system, the MnO2 core not only could be used as solid supporter to generate “hot spots” that can induce strong SERS signals, but also acted as the responsive unit for H2O2 sensing together with Ag NPs. A good linear relationship in the range from 1 to 100 μM and limit of detection of 7.44 μM were obtained. Moreover, the nanosensor possessed good repeatability. Based on this strategy, the sensitive detection of cellular H2O2 was achieved. Furthermore, the SERS-based H2O2 monitoring during the starvation-induced autophagy was realized by the developed nanoprobes. Our study provides a new way for sensitive H2O2 detection and opens a new avenue for sensing and detection of other biomolecules.