|Artificial cilia could someday power diagnostic devices
Researchers have developed a micro-sized artificial cilial system based on platinum-based components that can control fluid movement at such a small scale. Low-cost, portable diagnostic gadgets for evaluating blood samples, manipulating cells, and assisting in microfabrication processes could be possible in the future thanks to this technology.
The attentive ushers of the body are Cilia. These microscopic hairs are crucial for moving cerebrospinal fluid into your brain, eliminating mucus and dirt from your lungs, and keeping other organs and tissues clean through the rhythmic pounding.
Cilia, despite being a technological marvel, have been difficult to replicate in engineering applications, particularly at the microscale.
Cornell University researchers have developed a micro-sized artificial cilial system based on platinum-based components that can control fluid movement at such a small scale. Low-cost, portable diagnostic gadgets for evaluating blood samples, manipulating cells, and assisting in microfabrication processes could be possible in the future thanks to this technology.
"Cilia Metasurfaces for Electronically Programmable Microfluidic Manipulation," a paper by the group, was published in Nature on May 25. Wei Wang, a Ph.D. student, is the principal author.
"There are a variety of approaches to creating artificial cilia that respond to light, magnetic, or electrostatic stimuli," Wang explained. "However, we are the first to employ our novel nano actuator to create individually controlled artificial cilia."
The effort, directed by Itai Cohen, professor of physics at the College of Arts and Sciences, builds on a platinum-based, an electrically powered actuator that his lab previously developed to enable microscopic robots to walk. Although the mechanics of those bending bot legs are identical, the cilia system's function and uses are distinct and adaptable.
""What we're showing here is that once you can address each cilia individually, you can alter the fluxes in whatever way you want," Cohen explained. Multiple independent trajectories, circular flow, transport, and flows that break into two directions and then rejoin are all possible. Flow lines are available in three dimensions. It is possible to achieve anything."
"Using existing platforms to produce cilia that are tiny, work in water, are electrically addressable, and can be integrated with intriguing electronics has proven to be quite difficult," Cohen said. "These issues are addressed by this system. We hope to construct the next generation of microfluid manipulation devices using this platform."
A typical device consists of a chip with 16 square units, each having eight cilia arrays and eight cilia, each about 50 micrometers long, resulting in a "carpet" of about a thousand artificial cilia. The surface of each cilium oxidizes and reduces periodically as the voltage on it oscillates, causing the cilium to bend back and forth and pump fluid at tens of microns per second. Different arrays can be engaged independently, resulting in an infinite number of flow patterns that match their biological counterparts' flexibility.
A cilia device with a complementary metal-oxide-semiconductor (CMOS) clock circuit — essentially an electronic "brain" that allows the cilia to operate without being tied to a traditional computer system — was also developed as a bonus. This opens the way for a slew of low-cost diagnostic assays to be developed for use in the field.
"You can envision people taking this tiny centimeter-by-centimeter device in the future, putting a drop of blood on it, and doing all the tests," Cohen said. "You wouldn't need a complicated pump or any other equipment; all you'd need to do is place it in the sunshine and it would operate. It could cost anywhere from $1 and $10."
Former postdoctoral researchers Alejandro Cortese, Ph.D. '19, and Marc Miskin; Michael Cao '14, Ph.D. '20; David Muller, the Samuel B. Eckert Professor of Engineering; Alyosha Molnar, associate professor of electrical and computer engineering; Paul McEuen, the John A. Newman Professor of Physical Science; and Ivan Tanasijevic and Eric Lauga of the University of Cambridge are among the co-
The Army Project Office, the National Science Foundation, the Cornell Center for Materials Research, which is funded by the NSF's MRSEC program, the Air Force Office of Scientific Research and the Kavli Institute at Cornell for Nanoscale Science were the primary funders of the research.
Part of the work was done at Cornell's NanoScale Science and Technology Facility.
Materials provided by Cornell University.
Wei Wang, Qingkun Liu, Ivan Tanasijevic, Michael F. Reynolds, Alejandro J. Cortese, Marc Z. Miskin, Michael C. Cao, David A. Muller, Alyosha C. Molnar, Eric Lauga, Paul L. McEuen, Itai Cohen. Cilia metasurfaces for electronically programmable microfluidic manipulation. Nature, 2022; 605 (7911): 681 DOI: 10.1038/s41586-022-04645-w