Abstract: The invention is directed to droplet actuator devices and assay methods. The method may include, among other things, a method of conducting enzymatic assays using umbelliferone substrates with cyclodextrins in droplets in oil, the method including incubating a droplet in oil, the droplet preferably comprising an umbelliferone substrate, a sample, and a cyclodextrin compound. The methods may further include a method of substantially eliminating cross-contamination between droplets in enzymatic containing substrate-based bioassays. The method may include immobilization of the enzymatic substrate including forming an inclusion complex with the substrate for stabilizing the substrate within an aqueous environment, wherein the inclusion complex may be formed using cyclodextrins. In yet another embodiment, the invention may provide a method of enhancing hydrolysis of enzymatic substrates.

Abstract: The invention is directed to droplet actuator devices and assay methods. The method may include, among other things, a method of conducting enzymatic assays using umbelliferone substrates with cyclodextrins in droplets in oil, the method including incubating a droplet in oil, the droplet preferably comprising an umbelliferone substrate, a sample, and a cyclodextrin compound. The methods may further include a method of substantially eliminating cross-contamination between droplets in enzymatic containing substrate-based bioassays. The method may include immobilization of the enzymatic substrate including forming an inclusion complex with the substrate for stabilizing the substrate within an aqueous environment, wherein the inclusion complex may be formed using cyclodextrins. In yet another embodiment, the invention may provide a method of enhancing hydrolysis of enzymatic substrates.

Abstract: The present invention provides improved synthetic polymer hydrogel permeation layers for use on active electronic matrix devices for biological assays. The present invention includes methods for forming a permeation layer on an array of microelectrodes including the steps of attaching a linker to the surface of the array and providing a polymerization solution that includes a porogen. The surface of the array is then contacted with the polymerization solution and the polymerization solution is then polymerized on the surface of the array to form a permeation layer that is attached o the surface of the array through the linker. The porogen is then removed from the permeation layer, thereby creating void spaces in the permeation layer.

Abstract: The present invention provides improved synthetic polymer hydrogel permeation layers for use on active electronic matrix devices for biological assays. The present invention includes methods for forming a permeation layer on an array of microelectrodes including the steps of attaching a linker to the surface of the array by treating the surface with a linker by vapor deposition and providing a polymerization solution that includes at least one monomer having a polymerizable moiety, a modified streptavidin, a surfactant or porogen, and a cross-linking agent. The surface of the array is then contacted with the polymerization solution and the polymerization solution is then polymerized on the surface of the array to form a permeation layer that is attached o the surface of the array through the linker.

Abstract: Electronically addressable microchips having covalently bound permeation layers and methods of making such covalently bonded permeation layers to microchips are provided. The covalent bonding is derived from combining the use of electrodes with silane derivatives. Such chemistry provides the ability to apply an electronic bias to the electrodes of the microchip while preventing permeation layer delaminating from the electrode surface. Methods for covalently attaching the permeation layer to the microchips are also described.