A sensitive hydrogen peroxide and glucose biosensor based on gold/silver core–shell nanorods

Au core/Ag shell nanorods (Au@Ag NRs) were synthesized through the seed-mediated growth procedure using Au nanorods (Au NRs) as templates and characterized by UV–vis and TEM methods. The as-prepared Au@Ag NRs were used as a new electrode material for construction of sensor by surface casting of Au@Ag NRs aqueous solution on a glassy carbon electrode (GCE). The fabricated sensor exhibits excellent catalytic performance toward H2O2 reduction with a fast amperometric response time of less than 2 s, a wide linear response ranging from 0.02 to 7.02 mM (R = 0.99), and a lower detection limit of 0.67 μM estimated on a signal-to-noise ratio of 3. A glucose biosensor was further fabricated by immobilization of glucose oxidase (GOD) onto the core/shell Au@Ag NRs-modified GCE. The resultant biosensor exhibits high sensitivity, selectivity and stability for glucose detection in phosphate buffer solution. Even in human blood serum, the biosensor also exhibits good performance for glucose detection with an enhanced sensitivity of 33.67 μA mM−1 cm−2.