Pt-Pd bimetallic nanocoral modified carbon fiber microelectrode as a sensitive hydrogen peroxide sensor for cellular detection

In this work, an ultrasensitive microelectrode for hydrogen peroxide (H 2 O 2 ) detection was constructed. The carbon fiber microelectrode (CFME) was modified with Pt-Pd nanocoral (Pt-Pd/CFME) by using a one-step electrochemical deposition method. Compared to Pt/CFME and Pd/CFME, the Pt-Pd/CFME has larger active surface area and faster electron transfer efficiency, thus exhibiting higher electrocatalytic activity for H 2 O 2 sensing. Under the optimal condition, the Pt-Pd/CFME presents fast response time (≤5 s), high selectivity (11.6 mA mM −1  cm −2 ), wide linear range (5–3920 μM) and low detection limit (0.42 μM, S/N = 3) for H 2 O 2 detection. Furthermore, the proposed sensor was successfully employed to monitor H 2 O 2 released from A549 living cells, and the detection of H 2 O 2 in milk was also realized. With the above attractive electrocatalytic properties and convenient fabrication process, the as-prepared microelectrode provides unique advantages in the monitor of H 2 O 2 in biological samples, especially in cellular environment.