Design of robotic magnetic bead handling instrument (MAGrahder). (A) A lateral view shows how magnetic beads are extracted from a drop, transferred into the next drop and mixed by MAGrahder. When the neodymium permanent magnet rod contacts the thin glass surface of the MAGrahd reactor tray from outside near the drops, the magnetic beads in the drops collect at the surface of the glass plate. The beads are then transported to subsequent drops where they are released by removing the magnetic rod from the glass plate. (B) A lateral view of the MAGrahd tray reactor after set-up. (C) General view of the MAGrahder. (1) Computer control; (2) the deck of the ShotMaster 300 that is equipped with six MAGrahd reactor trays; (3) robotic arm; (4) temperature controller. (D) Image of the robotic arm with 12-channel magnetic rods transferring magnetic beads in the MAGrahd reactor tray.