Digital microfluidics devices and methods of using them

A digital microfluidics (DMF) reader device configured to operate with a removable cartridge, the device comprising:

• a cartridge seat configured to seat the removable cartridge;
• one or more vacuum ports in the cartridge seat configured to apply a negative pressure to secure the cartridge in the cartridge seat;
• an array of drive electrodes on the cartridge seat, the array of drive electrodes configured to apply a voltage to move a droplet within the cartridge by electrowetting;
• a clamp configured to move from an open clamp configuration in which the cartridge seat is exposed and a closed clamp configuration in which the clamp is latched over the cartridge seat so that at least one or more edges of the cartridge seat are covered by the clamp, wherein the clamp includes a window region allowing access to the cartridge when the cartridge is seated in the cartridge seat and the clamp is in the closed clamp configuration;
• a lid having an open lid configuration exposing the clamp and cartridge seat and a closed lid configuration in which the lid covers cartridge seat and the clamp when the clamp is in the closed clamp configuration;
• and
• a safety interlock configured to disable application of the voltage to the array of drive electrodes unless the cartridge is seated in the cartridge seat, the clamp is in the closed clamp configuration and the one or more vacuum ports are applying the negative pressure to secure the cartridge in the cartridge seat.