An Electrowetting on Dielectrics Based Lab-on-a-Chip Utilizing an Integrated High Fundamental Frequency Quartz Crystal Resonator as a Biosensor

We demonstrate the operation of an Electro Wetting on Dielectrics (EWOD) hybrid lab-on-a-chip system by utilizing a High Fundamental Frequency (HFF; 50MHz) Quartz Crystal Microbalance (QCM) resonator as masssensitive sensor. In a first experiment we have tested the reversible formation of a phosphor-lipid monolayer out of an aqueous buffer suspension of phospholipid vesicles onto the integrated sensor, coated by a Self-Assembled Monolayer (SAM) of 1-octadecanethiol on a gold-covered surface. The altered mass load resulted in a shift of the resonance frequencies. In the second experiment, the formation of a protein multilayer composed of streptavidin and biotinylated immunoglobulin G was monitored. The original resonance frequency was recovered by the complete lipid removal by the detergent octyl-D-glucopyranoside. Using these sample applications, we were able to demonstrate and verify the feasibility of our prototype combining a mass-sensitive QCM sensor with digital microfluidics based on EWOD.