Microfluidic Chip


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Contact:Jie Xu

A novel technique of in-chip drop on demand has been developed to dispense individual picoliter to nanoliter drops directly in the liquid-filled channels, with precise size and timing control.


–          Drops can be generated continuously at up to 2.5 kHz.

–          Drops with volumes from 25 pL to 4.5 nL can be precisely generated by varying pulse shapes and nozzle sizes.

–          At low dispense rate, the standard deviation of drop volumes is measured to be less than 2 %.


Merging and mixing two drops of different reagents


Digital control of drop volume


Dual-drop dispense, where two drops are generated simultaneously by a single pulse


Particle encapsulation in a single drop


In addition to dispensing drops, the piezoelectric actuation technique can be used to dispense a single bubble on demand in the main channel.


Funding: NSF grants 0449269 and 0701729 and Columbia Medical School.

Xu J. and Attinger D, Drop on demand in a microfluidic chip,  Journal of Micromechanics and Microengineering, Vol 18, pp 065020, 2008.