Patterned gold electrode prepared from optical discs display largely enhanced electrochemical sensitivity as exemplified in a sensor for hydrogen peroxide

Gold film electrodes (Au-FE) with distinct nanostructured patterns were prepared from polycarbonate (PC) substrates and investigated with respect to their analytical sensitivity. The recordable (R) and read-only memory (ROM) discs, respectively, yield PC substrates with grooves (stripe pattern) or pits (indented pattern). The Au-FEs were characterized in terms of surface morphology and surface patterns, and it was found that the surface area of all Au-FEs does not significantly differ (by 0.2 to 7.4 %) compared to electrode with flat surfaces. However, the electrical signal of indented patterns is larger by 32 to 213 % when directly compared to stripe-patterned Au-FEs (at the same scale of groove and pit). An Au-FE prepared from a polycarbonate sheet from a Blu-ray disc read only memory (BD-ROM) as substrate displayed the best electrochemical performance towards reductive sensing of H2O2. The respective calibration plot, acquired at a working potential of -0.1 V vs. Ag/AgCl, covers the 0 to 10 mM hydrogen peroxide concentration range. The sensitivity is as high as 3.11 mu Aa (TM) mM(-1)a (TM) cm(-2) which is larger by a factor of 28 compared to flat gold electrodes, and the detection limit (at a signal-to-noise ratio of 3) is 6 mu M. Therefore, the results confirm that the indented nanopattern on the Au-FE significantly increases the efficiency of electrochemical detection. Conceivably, the surface patterns and structures may be designed in order to tune sensitivity with respect to future applications of Au-FEs in diagnostics, agriculture, and environmental monitoring.