Implantable nanosensor with thin-layer hydrogel antifouling interface for ultrasensitive detection of hydrogen peroxide at the single-cell level

An antifouling nanosensor was constructed with a thin-layer hydrogel interface for effectively resisting non-specific adsorption. • Gel/Pt/CFE achieved ultrasensitive and accurate detection of H 2 O 2 with a low LOD of 1.093 μM. • The nanosensing platform enabled spatiotemporal-resolution monitoring of H 2 O 2 levels in PC-12 cells at the single-cell level. Accurate detection of endogenous hydrogen peroxide (H 2 O 2 ) at the single-cell level is crucial for elucidating its important roles in cellular signaling and oxidative stress. However, the accuracy of nanoelectrochemical sensors is severely hindered by non-specific adsorption at the sensing interface in complex cellular environments. The adsorption of proteins and other biomolecules can significantly passivate the electrode interface, leading to signal shifts and unreliable monitoring. Herein, an innovative implantable nanosensor with robust antifouling interface was developed by electrodepositing platinum nanoparticles onto a carbon fiber electrode, followed by the in-situ synthesis of hydrophilic poly(ethylene glycol) diacrylate hydrogel layer. The hydrogel layer served as a highly effective diffusion barrier against non-specific adsorption of proteins and other interferents while remaining permeable to H 2 O 2 molecules. The results demonstrated that the proposed nanosensor had excellent sensitivity and stability for H 2 O 2 detection ranging from 10 to 1000 μM, with a detection limit of 1.093 μM (S/N = 3), enabling in-situ monitoring of intracellular H 2 O 2 fluctuations in single cells with high accuracy. This work provides a reliable platform for nanoelectrochemical sensing toward small biomolecules in complex biological matrices. Download: Download high-res image (209KB) Download: Download full-size image