Automated Liquid Handler

Overview

An automated liquid handler is a pipetting robot. It does by machine what a scientist does by hand with a pipette: pick up a tip, draw a measured volume of liquid from one well, move it, and dispense it into another. The difference is scale and consistency. A handler runs an entire 96- or 384-well plate the same way every time, unattended, hundreds of transfers per minute, which is what makes assay development, drug screening, genomics sample prep and NGS library construction practical at volume.

The work surface is a flat deck of fixed positions. Plates, reagent reservoirs and boxes of disposable tips sit in kinematic nests at known coordinates, so the robot addresses each one blind from its method file. A run is a list of aspirate-and-dispense steps the software walks through, and the deck layout tells it where everything is.

How it works

Every position is reachable because the pipettor rides a three-axis robot, the X-Y-Z Gantry. A bridge moves in Y, a carriage in X and the head plunges in Z, each a servo motor turning a ball-screw under encoder feedback, so the tips arrive over any well to a fraction of a millimeter. The labware it works on sits on the Labware Deck, whose nests register each plate and tip rack in a repeatable spot.

The transfers themselves come from the Pipetting Head, a row of independent air-displacement channels that pick up tips, aspirate and dispense, then eject the tips to waste. Each channel is fed by its own pump in the Syringe Pump Bank bank, where a glass syringe driven by a ball-screw displaces an exact volume and solenoid valves route between aspirate, dispense and wash.

Accuracy depends on knowing the liquid is really there. The Liquid Sensing module uses a capacitive sensor on each tip to find the surface so the tip dips just below it, and a pressure transducer watches each draw to catch a clot or an empty well. Between samples the head visits the Wash Station to flush carryover. Coordinating all of it, the Control Electronics pair a single-board computer running the method with a motion controller that drives the gantry servos and syringe pumps in lockstep.