Scientists from the University of Buffalo, New York, have developed a microchip that enables them to dirigate the movement of liquids in micro- and nano-sized channels. This is achieved by capillary and vacuum forces.

 

Under the direction of Prof. Kwang W. Oh from the Department of Electrical Engineering at the University at Buffalo, the researchers have solved the problem that liquids of different densities or volume cannot be mixed due to pressure gradients in microchannels and even often flow back out of the channel.

 

The scientists constructed a kind of bypass between the inlet of two microchannels. With the help of a syringe, the liquids are pulled into a mixing channel through the generated vacuum. They successfully tested their model by determining the different blood groups that were mixed with an antibody. Due to different properties of the blood, they take different lengths of time, to flow through the microchannel, making it possible to differentiate between the boold groups.

 

The researchers published their model in Lab on a Chip magazine.
Zhai, Y., Wang, A., Koh, D., Schneider, P. & Oh, K. W. (2018). A robust, portable and backflow-free micromixing device based on both capillary and vacuum-driven flows. Lab on a Chip 2.
http://pubs.rsc.org/en/content/articlelanding/2018/lc/c7lc01077j#!divAbstract

 

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