Fabrication of ultrafine PtPd alloy/ionic liquid-carbon dots nanocomposites modified flexible carbon fiber as enzyme-free amperometric sensing for H2O2 in living cells

Given the pivotal role of hydrogen peroxide (H 2 O 2 ) in numerous biological progresses, there has been a recent surge in the development of highly effective electrochemical sensors for H 2 O 2 detection. In this article, we propose an enzyme-free amperometric system for the sensitive and selective recognition of H 2 O 2 , leveraging ultrafine PtPd alloy/ionic liquid-carbon dots (IL-CDs) nanocomposites modified flexible carbon fiber. The IL-CDs were synthesized through the direct electrodeposition of ionic liquid [BMIM][PF 6 ] using Pt sheets as electrodes. Subsequently, a sequential electrodeposition of IL-CDs, H 2 PtCl 6 , and PdCl 2 onto the activated carbon fiber (ACF) yielded the PtPd/IL-CDs/ACF microelectrode. This microelectrode serves as an enzyme-free amperometric sensor for H 2 O 2 detection, exhibiting an improved response with a significantly lower detection limit of 0.29 μM and a relatively broad linear range spanning from 2 to 6561 μM. Furthermore, this enzyme-free amperometric H 2 O 2 sensor demonstrates remarkable stability over extended periods and exceptional performance in practical applications, such as the analysis of commercially available milk, human serum, human urine, and living cancer cells analysis. This study offers a fresh perspective on amperometric sensors based on metal alloys and CDs electrode, highlighting the potential of enzyme-independent detection for hydrogen peroxide in biological systems.