Devices and methods for depositing fluids on substrates in patterns of
spots, lines, or other features use a nozzle, which is preferably
configured similarly to a micropipette, having a piezoelectric crystal or
other ultrasonic actuator coupled to one of its sides. The nozzle may be
charged via capillary action by dipping it into a well containing the
fluid to be deposited, and may then be positioned over a desired area of a
substrate, at which point activation of the ultrasonic actuator at
ultrasonic frequencies will eject the fluid onto the substrate. The needle
may subsequently be dipped into a well of rinsing fluid for cleaning.
Spots or lines on the order of 5 micrometers width may be generated,
making the invention particularly suitable for use in biological
applications such as microarray production and in microelectronics
applications such as the printing of organic circuitry.
