PROJECT SUMMARY This project seeks to make drug discovery more effective by making the screening technology more accessible. Currently, new drug leads are discovered by testing a large number of unknown chemicals to see if any have the effect that you are looking for. Since this process is somewhat slow and expensive, such testing is not as thorough and widespread as it should be. We are trying to allow the chemical reactions to be run in microscopic droplets of liquid, which would greatly lower the cost of these reactions and make it possible to run many more together at once. To accomplish this, we are building a new device, a gigantic array of droplet dispensers. The array is envisioned to be large enough to hold the entire set of unknown chemicals that you are interested in testing. The array is very flexible. It can quickly dispense the entire set of chemicals, dispense many different concentrations of each chemical so that we can find the most effective dose, or dispense the chemicals in a variety of different combinations so that we can discover which drugs work well together. In order to make this array of dispensers work, we are using a new type of microchip technology where the circuits carry liquids instead of electrons. What is unique about our liquid circuits is that they can perform computations much like a computer can. This ends up being very useful for this project because we use this computational power to control the large array of dispensers. We originally proposed to fabricate the microchip prototypes by CNC micro-milling. While this is an effective approach, the manufacturing process is extremely time and labor intensive. Recently, 3D printing has advanced to the point that 10-micron pixel resolution can be achieved in printers affordable enough to be housed in individual laboratories. We request an administrative supplement to purchase our own high-resolution 3D printer. This will greatly reduce the time to complete each design-build-test engineering cycle, allowing us to iterate and optimize our devices much more quickly.