In-situ growth G4-nanowire-driven electrochemical biosensor for probing H2O2 in living cell and the activity of terminal deoxynucleotidyl transferase

Cancer cells require higher ROS levels to maintain their growth state of rapid division and spread·H 2 O 2 , as a kind of usual ROS molecule, is monitored by designing a new in-situ growth G4-nanowire-driven electrochemical biosensor, which is further used for probing H 2 O 2 released by rat astroglioma cell. In this process, the electrocatalytic performance to H 2 O 2 of G4-nanowire (containing G-quadruplex/hemin nanostructures) is employed as signal output, which is constructed by terminal deoxynucleotidyl transferase (TdT)-mediated polymerization in the dNTPs pool of dTTP and dGTP (4: 6). Then, the method is applied for H 2 O 2 monitoring in the range of 0.0003 ∼ 6 mM and the detection limit is estimated to be 0.075 μM (S/N = 3). More importantly, the content of H 2 O 2 generated in rat astroglioma cell is also calculated roughly, displaying an excellent feasibility for the related physiological and pathological studies. Later, TdT activity and its inhibitors are also probed orderly, and a wide linear range is presented with a detection limit of 0.81 mU/mL. It is hoped that the designed platform will provide a reference for exploring new ways to continuous dynamic surveillance of diseases in diagnosis and treatment stage.