The invention relates to improved methods of loading aqueous reagents into electrowetting devices which are often hydrophobic and therefore problematic to load. Disclosed is a method for moving an aqueous droplet from an inlet port onto an EWoD device by actuating a temporary inlet path.

An electrowetting device comprising a cell comprising a working electrode that is formed of a laminar material having a working surface having a surface roughness R.sub.q of 20 nm or less. A suitable laminar material is HOPG.

A pico-droplet generator includes a light sensing structure, a mating structure that is spaced apart from the light sensing structure, a bonding layer that connects the light sensing structure and the mating structure, and a piezoelectric member that is disposed on the bonding layer. The pico-droplet generator defines a selection channel along a flowing direction. The bonding layer has a selection hole that is in spatial communication with the selection channel along a dripping direction perpendicular to the flowing direction. The piezoelectric member and the selection hole are respectively arranged on two opposite sides of the bonding layer. The pico-droplet generator has a pico-droplet emission region that is defined from the selection hole toward the piezoelectric member.

A system for fluid transport is provided where a quantity of fluid is held in a reservoir. A droplet generator is employed to generate droplets from the fluid, for example a nozzle-based system or a nozzleless system such as an acoustic ejection system. A generated droplet has a trajectory whereby it arrives at a target. A circuit is used to modify one or more characteristics of the generated droplet in a way which increases the likelihood that the droplet will not splash or bounce when it arrives at the target. The circuit may in different embodiments control the speed of the droplet or the Weber number of the droplet. The circuit may create an electric field in an area of space where the droplet passes. The circuit may charge the droplet by causing it to contact ions.

A system for fluid transport is provided where a quantity of fluid is held in a reservoir. A droplet generator is employed to generate droplets from the fluid, for example a nozzle-based system or a nozzleless system such as an acoustic ejection system. A generated droplet has a trajectory whereby it arrives at a target. A circuit is used to modify one or more characteristics of the generated droplet in a way which increases the likelihood that the droplet will not splash or bounce when it arrives at the target. The circuit may in different embodiments control the speed of the droplet or the Weber number of the droplet. The circuit may create an electric field in an area of space where the droplet passes. The circuit may charge the droplet by causing it to contact ions.