Superhydrophilic edge-rich graphene for the simultaneous and disposable sensing of dopamine, ascorbic acid, and uric acid

A simple and rapid simultaneous sensing strategy of multiple biomarkers is of great importance but challenging in health diagnosis. In this study, a novel free-standing edge-rich graphene film (fs-ERG) was in situ fabricated via a facile chemical vapor deposition route on a porous Si₃N₄ substrate. The subsequent superhydrophilic modification of the fs-ERG not only makes it maintain the original abundant edge-rich sites, high conductivity, and hierarchical porosity, but also endows it with collective electrochemical characteristics. Thereafter, the superhydrophilic fs-ERG (S-fs-ERG) demonstrated a fast electron-transfer kinetics towards the oxidation of dopamine (DA), ascorbic acid (AA), and uric acid (UA), which promised a sensitive simultaneous electrochemical determination with low detectable limits of 0.1, 2.5 and 0.5 μM, respectively. Furthermore, this sensing electrode displayed high selectivity in the presence of co-existing interferences as well as excellent reproducibility, and thus performed well in DA, AA and UA detection in real samples. These superior sensing performance metrics combined with the low-cost and scalable fabrication of S-fs-ERG based electrodes bode well for their great potential for the simultaneous and disposable sensing of DA, AA and UA in practical application.