Templated Fabrication of Periodic Arrays of Metallic Attoliter Petri Dishes

Abstract

Arrays of microcontainers, which allow handling and isolating a small volume of liquids, are of great technological importance in the miniaturization of analytical and bioanalytical techniques. Here we report a scalable bottom-up approach for fabricating wafer-sized, periodic arrays of metallic Petri dishes with a volume as small as 10 attoliter/dish. A monolayer, nonclose-packed colloidal crystal prepared by a spin-coating technology is first used as a structural template to create ordered microwells with vertical sidewalls. Sputtering deposition of metals on the microwells, followed by removal of template, results in the formation of isolated metallic Petri dishes. The size, separation, depth, thickness, and metal types of the resulting Petri dishes can be easily tuned by adjusting the size of the colloidal microspheres and the templating conditions. We have also demonstrated that templated gold Petri dish arrays show strong surface-enhanced Raman scattering from adsorbed benzenethiol molecules. This bottom-up technology is compatible with standard microfabrication, promising for applications ranging from biomicroanalysis to surface plasmon devices.