Method and Apparatus for electrically actuated dispensing of microdrops

摘要

The multi-channel dispensing head has micropipettes in a two-dimensional array on a common carrier. A holder takes each micropipette, with a mass and signal contact separated from each other at the carrier. In the first dimension, the micropipettes are in straight or circular rows, with the mass contacts in each row, electrically interconnected, and each signal contact is linked to a multiplex circuit for separate control. In the second dimension, the micropipettes form a number of columns at an angle or at right angles to the micropipette rows, with mass contacts. The mass contacts, linked in the rows, are linked to a second multiplex circuit for separate control. The signal contacts in the columns are electrically interconnected, and are linked to the first multiplex circuit with individual control. The micropipettes are arranged in a matrix layout in rows and columns at right angles or at an angle to each other. The mass contacts in the rows and the signal contacts in the columns are connected electrically, while the common mass contacts in each separate row and the common signal contacts in each separate column are connected to the first and second multiplex circuits with separate control. The micropipettes are in a microtitration plate and a screen of reservoirs. The mass and signal contacts are springs, to form the holders and locks for the inserted micropipettes. The multiplex circuits and a power supply are fitted to the dispenser head and move with it. Each has a multiplexer and a circuit, where each circuit has a number of switches according to the mass contacts at the rows and the signal contacts at the columns. Each of the micropipettes has a pressure line from the distributor connected to a pressure supply line. The distributor is a multi-valve or a branch unit. The operating unit for the micropipette is a piezo electric element. An independent claim is included for an operation where the micropipettes are filled simultaneously with a volume of a carrier fluid from the operating unit to the charging volume at the pipette tip, and to carry pressure from the operating unit to the charge volume. Active ingredients are added. Preferred Features: The pipettes are charged with the volumes by lowering the micropipettes into a matrix of active ingredient reservoirs simultaneously. The charge volumes take up the active ingredient in the sub-ml range, and significantly less than the carrier volume.