Magnetic cilia should prevent lab-on-a-chip channels from silting up

Scientists from Eindhoven University of Technology have developed artificial magnetic cilia for the microchannels of lab-on-a-chip applications. The hairs can prevent and unblock blockages in the canals.

Chinese PhD student Shuaizhong Zhang of the Microsystems group at TU/e ​​made cilia with a diameter of fifty micrometers, which are driven by magnetic fields. The hairs can be made a lot smaller than the ones he developed, he reports in Cursor, the magazine of the university. Judging by the image, it concerns hairs with a length of three to four hundred micrometers. The PhD student showed that the control functions in practice, whereas until now this was only suspected on the basis of computer simulations.

The cilia must ensure good flow through the microchannels of a lab-on-a-chip and prevent congestion. A lab-on-a-chip or loc is an integrated circuit for the analysis of laboratory applications in the medical field, among others. The locomotives often contain sensors, pumps and channels to transport fluids such as blood, saliva, or urine.

Zhang demonstrated how he could remove artificial congestion in the form of small spheres of different sizes or the clogging by algae by moving a magnet around the locomotive. He also showed that the cilia can be used to propel liquids, eliminating the need for a pump.

His method works better than existing methods. There are already hollow cilia that function by blowing air through them, but these are difficult to make small. Electric fields to control cilia have a negative side effect that they affect cells, for example. Zhang will further investigate whether non-uniform magnetic fields can be used for the metachronous movement of the cilia, which create a wavy movement for efficient propulsion.

Update, 15.00: Adjusted to refer to hairs with diameter rather than length of 50 micrometers, based on clarification in Cursor’s article.

Example of artificial cilia developed by the Microsystems group at TU/e