Fabrication of microfluidic devices for AC electrokinetic fluid pumping

Two techniques for the fabrication of novel microfluidic devices for electrokinetic fluid pumping are presented. Both consist of forming a micro-channel and reservoirs on a transparent cover sheet and patterning an array of interdigitated asymmetric micro-electrodes on a flat substrate. The two techniques differ from each other in their building materials as well as the pattern replication technique used for the cover sheet fabrication. In the first approach, we used a glass substrate for the electrode fabrication and casting of an elastomer for the cover sheet. In the second approach, both cover sheet and substrate are obtained by imprinting plastic pellets on a pre-patterned or flat mold. In assembled devices, pumping has been demonstrated and characterized by optical microscopy. The observed dependence of the pumping velocity on applied voltage and frequency are in line with theoretical predictions. (C) 2002 Elsevier Science B.V. All rights reserved.