Multichannel Stimulus-Responsive Nanoprobes for H₂O₂ Sensing in Diverse Biological Milieus

Hydrogen peroxide (H₂O₂) is widely involved in various physiological or pathological processes such as cell differentiation, proliferation, tumorigenesis, and immune responses. The accurate detection of H₂O₂ is highly required in many situations ranging from chemical sensing to biomedical diagnosis. However, it is exceedingly challenging to develop a single sensor that can respond to H₂O₂ in different conditions. Herein, a three-in-one stimulus-responsive nanoplatform (Au@MnO₂@Raman reporter) was designed for colorimetry/SERS/MR tri-channel H₂O₂ detection which satisfied different applications. The MnO₂ shell acted as a distance mediator between the gold nanoparticle (Au NP) core and the Raman reporter layer. In the presence of H₂O₂, the MnO₂ shell is degraded, thus releasing the Mn²⁺ and Au NP core, which act as magnetic resonance (MR) and colorimetry signals, respectively. Simultaneously, the Raman reporters adsorb on the exposed Au NPs, resulting in the surface-enhanced Raman scattering (SERS) effect. The Au NP-based colorimetric assay was employed as H₂O₂ sensors for glucose detection while the turn-on signals of SERS and MR were used for H₂O₂ sensing and imaging in live cells and tumors, showing great versatility and flexibility of the multichannel probes in diverse situations.