Electrochemistry in nanovials fabricated by combining screen printing and laser micromachining

The coupling of screen-printing and laser micromachining technology has been used to create a nanovial with "built-in" working and reference electrodes. The volume of the nanovial was calculated to be 7.2 nL using dimensions determined by SEM. The electrochemical nanovial was characterized using the ferri/ferrocyanide redox couple. Cyclic voltammetry and chronoamperometry experiments were performed with electrochemical nanovials utilizing 5% (v/v) glycerin in the solutions and a humidified headspace to control evaporation of the small-volume samples. Chronoamperometry experiments gave results consistent with a diffusion-limited process and revealed a working electrode surface area of 2.6 x 10(4) micron 2. The ultrasmall-volume cells represent a simple, reliable, low-cost approach for the fabrication of complete electrochemical nanovials.