Manipulating liquid flow with light

Chinese researchers have invented a new material to create light-activated micro-channels to transport liquid, which is likely to bring about breakthroughs in medical lab tests, as well as chemical engineering, aviation and aerospace industries.

Scientists believed that microfluidic chips can be applicable in various sectors, including medical lab tests, but the bottleneck for experts in the circle was that it needed an add-on pump, which is often large, to drive the liquid to flow. Therefore even though the chip is tiny enough, it is hard for the whole device to become small and portable.

Researchers from Shanghai-based Fudan University invented a special material to produce the channel to contain the liquid. Some certain changes in the shape of the channel will happen when light shines on the channel, and therefore the liquid will flow in a certain direction in the channel. "Thus we realized the manipulation of the liquid flow with light," said Yu Yanlei, a leading researcher on the team, whose research results were published on the website of the scientific journal Nature today.

Lyu Jiu'an, another researcher on the team, cited the example of its promising application in lab tests, and blood tests in particular.

"During the process of a test, a sample of blood needs to go to different stops in the channel for different steps, such as being purified and separated for the tests for various indicators. An add-on pump was used to drive the blood to run in the channel, but now we can cast the pump aside," Lyu said.

Researchers said small-sized and portable instruments for biochemical inspections, such as blood tests, will probably be developed with such technology, and people will be able to do blood tests by themselves at home.

Moreover, the tiny amount of material needed for a test sample will make collecting several tubes of blood from a patient history.

"In our tests, we only need a liquid sample of 0.2 microliter," Lyu said.