Automated molecular biology laboratory

An automated laboratory for transferring liquids from one container to another and performing a chemistry protocol comprising:

• a stationary worksurface having machined registration elements are accurately locating and supporting a modular container station for holding said containers of liquid;
• a pipette subsystem for aspirating and dispensing liquid, said pipette subsystem comprising a pipette tip coupled to a capacitance sensor;
• a robotic translation subsystem for moving said pipette tip to all containers on said worksurface and into and out of said containers;
• a heating subsystem for heating liquids in said containers;
• a cooling subsystem for cooling liquids in said containers;
• a gauge block securely fastened to and accurately positioned on said worksurface and having surfaces substantially orthogonal to directions of movement of said pipette tip by said robotic translation subsystem;
• and
• a control subsystem for automatically managing said chemistry protocol;
• wherein said control subsystem controls said robotic translation subsystem to move said pipette tip to each of said surfaces on said gauge block wherein the pipette tip and the capacitance sensor sense the position of the machined surface of said gauge block thereby establishing a home position on said worksurface for said liquid transfers.

A method for transferring liquid by a robotic translation system from a first container holding a first volume of liquid to a second container holding a second volume of liquid comprising steps of:

• aspirating a third volume of liquid from said first volume of liquid in said first container with a pipette having a pipette tip and a capacitance sensor for sensing the position of said pipette tip relative to proximate surfaces;
• moving said pipette tip away from said first container by action of said robotic translation system;
• dispensing a first droplet of liquid from said pipette tip such that said first droplet depends from said pipette tip but does not separate therefrom, said first droplet having a known droplet volume;
• moving said first droplet with said pipette tip by said robotic translation system until said first droplet touches the surface of said second volume of liquid, stopping translation when said capacitance sensor signals contact, and allowing said first droplet to become confluent with said second volume of liquid;
• withdrawing said pipette tip from said second volume of liquid;
• dispensing a second droplet of liquid from said pipette tip such that said second droplet of liquid depends from said pipette tip but does not separate therefrom, said second droplet having a volume equal to the volume of said first droplet;
• moving said second droplet with said pipette tip by said robotic translation system until said second droplet touches the surface of said second volume of liquid, stopping translation when said capacitance sensor signals contact, and allowing said second droplet to become confluent with said second volume of liquid;
• and
• repeating the steps of dispensing droplets and transferring the droplets to said second volume of liquid until a predetermined volume of liquid is dispensed and transferred to said second volume of liquid.

A method for checking for positions of elements on a worksurface in a liquid-handling instrument having a pipette subsystem, said pipette subsystem comprising a pipette tip coupled to a capacitance sensor for sensing position of said pipette tip relative to proximate surfaces, said pipette tip movable over said worksurface by a robotic translation subsystem, said method comprising the steps of:

• moving said pipette tip in a pattern and at a height over said worksurface such that said pipette tip will not contact any surface if every part is in its proper place;
• stopping translation of said pipette tip if said pipette tip contacts any surface as signalled by said capacitance sensor;
• and
• activating a signal that a part is out of position.

A method for mixing liquids in a liquid handling instrument having a pipette subsystem with a pipette tip movable over a worksurface by a robotic translation subsystem, said method comprising the steps of:

• moving said pipette tip by said robotic translation subsystem to immerse said pipette tip in a volume of liquid in a container;
• aspirating liquid into said pipette ending with said pipette tip immersed in said volume of liquid in said container;
• dispensing said aspirated liquid into said container while moving said pipette tip in a pattern encompassing substantially the space occupied by said volume of liquid in said con ruiner;
• and
• repeating the steps of aspirating and dispensing while moving said tip in said pattern to thoroughly mix the contents in said container.