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 (H2O2) 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 H2O2 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 mu M) and low detection limit (0.42 mu M, S/N = 3) for H2O2 detection. Furthermore, the proposed sensor was successfully employed to monitor H2O2 released from A549 living cells, and the detection of H2O2 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 H2O2 in biological samples, especially in cellular environment. (c) 2017 Elsevier B.V. All rights reserved.