In Situ Monitoring of Hydrogen Peroxide Released from Living Cells Using a ZIF-8-Based Surface-Enhanced Raman Scattering Sensor

Hydrogen peroxide (H₂O₂) widely involves in intracellular and intercellular redox signaling pathways, playing a vital role in regulating various physiological events. Nevertheless, current analytical methods for the H₂O₂ assay are often hindered by relatively long response time, low sensitivity, or self-interference. Herein, a zeolitic imidazolate framework-8 (ZIF-8)-based surface-enhanced Raman scattering (SERS) sensor has been developed to detect H₂O₂ released from living cells by depositing ZIF-8 over SERS active gold nanoparticles (AuNPs) grafted with H₂O₂-responsive probe molecules, 2-mercaptohydroquinone. Combining the superior fingerprint identification of SERS and the highly efficient enrichment and selective response of H₂O₂ by ZIF, the ZIF-8-based SERS sensor exhibits a high anti-interference ability for H₂O₂ detection, with a limit of detection as low as 0.357 nM. Satisfyingly, owing to the enhanced catalytic activity derived from the successful integration of AuNPs and ZIF, the response time as short as 1 min can be obtained, demonstrating the effectiveness of the SERS sensor for rapid H₂O₂ detection. Furthermore, the developed SERS sensor enables real-time detection of H₂O₂ secreted from living cells under phorbol myristate acetate stimulation, as cells can be cultured on-chip. This study will pave the way toward the development of a metal-organic framework-based SERS platform for application in the fields of biosensing and early disease diagnosis associated with H₂O₂ secretion, thus exhibiting promising potential for future therapies.