Methods are provided for separating magnetically responsive beads from a droplet in a droplet actuator. Droplet operations electrodes and a magnet are arranged in a droplet actuator to manipulate a bead-containing droplet and position it relative to a magnetic field region that attracts the magnetically responsive beads. The droplet operations electrodes are operated to control the droplet shape and transport it away from the magnetic field region to form a concentration of beads in the droplet. The continued transport of the droplet away from the magnetic field causes the concentration of beads to break away from the droplet to yield a small, concentrated bead-containing droplet immobilized by the magnet.

A sample processing station includes two or more container holders on a platform that is rotatable about a central axis of rotation. Each holder is configured to rotate about a secondary axis of rotation. The station includes a capping/decapping mechanism to cap or decap a container held in one of the container holders and an elevator with a chuck guide that contact the container holder as the chuck is lowered by the elevator to position the chuck with respect to the cap of the container held in the holder and to hold jaws of the container holder in a closed position. In embodiment, the chuck guide includes a yoke with opposed arms and spindles located near distal ends of the arms that engage beveled shoulders of the container holder.

Methods are provided for separating magnetically responsive beads from a droplet in a droplet actuator. Droplet operations electrodes and a magnet are arranged in a droplet actuator to manipulate a bead-containing droplet and position it relative to a magnetic field region that attracts the magnetically responsive beads. The droplet operations electrodes are operated to control the droplet shape and transport it away from the magnetic field region to form a concentration of beads in the droplet. The continued transport of the droplet away from the magnetic field causes the concentration of beads to break away from the droplet to yield a small, concentrated bead-containing droplet immobilized by the magnet.

A sample processing station includes two or more container holders on a platform that is rotatable about a central axis of rotation. Each holder is configured to rotate about a secondary axis of rotation. The station includes a capping/decapping mechanism to cap or decap a container held in one of the container holders and an elevator with a chuck guide that contact the container holder as the chuck is lowered by the elevator to positon the chuck with respect to the cap of the container held in the holder and to hold jaws of the container holder in a closed position. In embodiment, the chuck guide includes a yoke with opposed arms and spindles located near distal ends of the arms that engage beveled shoulders of the container holder.

A novel Self-Locking Optoelectronic Tweezers (SLOT) for single microparticle manipulation across a large area is provided. DEP forces generated from ring-shape lateral phototransistors are utilized for locking single microparticles or cells in the dark state. The locked microparticles or cells can be selectively released by optically deactivating these locking sites.

Provided herein are methods of splitting droplets containing magnetically responsive beads in a droplet actuator. A droplet actuator having a plurality of droplet operations electrodes configured to transport the droplet, and a magnetic field present at the droplet operations electrodes, is provided. The magnetically responsive beads in the droplet are immobilized using the magnetic field and the plurality of droplet operations electrodes are used to split the droplet into first and second droplets while the magnetically responsive beads remain substantially immobilized.

A novel Self-Locking Optoelectronic Tweezers (SLOT) for single microparticle manipulation across a large area is provided. DEP forces generated from ring-shape lateral phototransistors are utilized for locking single microparticles or cells in the dark state. The locked microparticles or cells can be selectively released by optically deactivating these locking sites.

Arrays of droplet-on-demand dispensers are controlled by a row-column addressing scheme that can reduce the number of on-chip address lines, thereby making it feasible to construct large dispenser arrays. Decoders are used to further reduce the number of control lines that select a specific address line. A microfluidic logic controller includes row-select lines, each coupled to dispensers disposed on the same row, and column-select lines, each coupled to dispensers disposed on the same column such that each dispenser is associated with a unique row-column address. A logic circuit can actuate a dispenser only if the logic circuit receives signals from both of the row-select line and the column-select line corresponding to the row-column address of the selected dispenser. Reagents can be dispensed from the dispenser array, thereby allowing for rapid formatting of a reagent library into microfluidic droplets.

A sample processing station includes two or more container holders on a platform that is rotatable about a central axis of rotation. Each holder is configured to rotate about a secondary axis of rotation. The station includes a capping/decapping mechanism to cap or decap a container held in one of the container holders and an elevator with a chuck guide that contact the container holder as the chuck is lowered by the elevator to positon the chuck with respect to the cap of the container held in the holder and to hold jaws of the container holder in a closed position. In embodiment, the chuck guide includes a yoke with opposed arms and spindles located near distal ends of the arms that engage beveled shoulders of the container holder.

Systems and methods for analysing a fluid including a fluid sample delivery application. The system includes a sensing element configured to respond to at least one analyte in a sample of fluid. A detector is provided, configured to sense the response to the analyte by the sensing element. The fluid sample delivery apparatus includes a dosage needle configured to deliver the sample of fluid to the sensing element, at least one pump configured to control flow of fluid through the dosage needle, and at least one actuator configured to move the dosage needle relative to the sensing element. At least one controller is provided, configured to control the at least one pump and the at least one actuator.