Microfluidic Testing for LLNA Replacement

By: Katie Schaefer, Cosmetics & Toiletries magazine

Posted: February 26, 2010, from the March 2010 issue of Cosmetics & Toiletries.

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The company has been working on the technology for 13 months. It has established the artificial skin and microfluidic compartments of the chip and is now working on the lymph node compartment.

The Role of Microfluidics
The microfluidic channels in the chip employ an activity called chemotaxis. Yarmush explained that chemokines are placed at one end of the microfluidic channels and that the dendritic cells are attracted to these materials if they have a receptor that binds to them.

“We set up a chemical gradient that allows the cells to migrate, and we want to point them in the right direction, which is toward the T cell compartment,” said Yarmush.

The microfluidic channels therefore become a chemokine gradient, and if the cells sense the chemokine, they migrate to the higher concentration, which is near the lymph node.

Testing and Beyond
If a chemical is a potent sensitizer, T cells will proliferate in its presence and this mechanism is employed in the LLNA model. Determining the sensitization of a chemical in the LLNA can involve three different testing methods, according to Yarmush: “You can pick up the number of T cells, you can look at surface markers on the T cells, or you can look at what the T cells are secreting.” These same approaches can be used with the chip, and the company is exploring which method is best to determine sensitization.