Electrochemical sensing of H2O2 released from living cells based on AuPd alloy-modified PDA nanotubes

Abstract

The highly efficient detection method for hydrogen peroxide (H₂O₂) has been attracting significant attention. In this study, AuPd alloy-modified polydopamine (AuPd-PDA) nanotubes were prepared, and an electrochemical nonenzymatic sensor based on the AuPd-PDA nanotubes was developed. A single AuPd alloy on the surface of PDA nanotubes consisted of many smaller nanoparticles of size ranging several nanometers, which greatly enhanced the catalytic activity. In addition, PDA nanotubes, as carriers of AuPd alloys, were used to amplify the signal and improve the sensitivity of H₂O₂ sensors. Owing to its synergistic effect and structural advantage, the H₂O₂ sensor based on AuPd-PDA nanotubes exhibited good sensing performances, including a high sensitivity of 314.2 μA mM⁻¹ cm⁻², a wide linear range from 1.0 μM to 11.22 mM and a low detection limit of 0.26 μM (S/N, 3 : 1). Moreover, the detection of H₂O₂ in HeLa and Raw 264.7 cells was also achieved, which indicated that the sensors based on AuPd-PDA nanotubes could be used for real-time monitoring of H₂O₂ in physiological and pathological processes in a clinic.