Industry Intelligence: putting down roots
Researchers at the University of Rochester have created a simple metal pump that lifts liquid using the wicking process trees use to pull water from their roots to their leaves. Guo and an assistant created the novel pump using a femtosecond laser to form nanoscale and microscale pits, globules and strands across the metal’s surface. “We’re able to change the surface structure of almost any piece of metal so that we can control how liquid responds to it,” says Chunlei Guo, associate professor of optics at the university. “We can even control the direction in which the liquid flows, or whether liquid flows at all.” Potential application of the novel pump design include pumping microscopic amounts of liquid around medical diagnostic chips.
Using the wicking process, the pump can move liquids upwards at the rate of 1 cm/sec. against gravity. The nanostructures etched into the metal’s surface change the way liquid molecules interact with metal, allowing them to become attracted to each other. The degree of attraction between the liquid and metal can be varied by varying the parameters of the laser treatment. Adding laser-etched channels to the metal can further enhance the control of the liquid. Guo likens the pump to a “a huge waterway system shrunk down onto a tiny chip.” Because of the unique design, the pump could be used to “perform chemical or biological work with a tiny bit of liquid,” Guo says. “Blood could precisely travel along a certain path to a sensor for disease diagnostics. With such a tiny system, a nurse wouldn’t need to draw a whole tube of blood for a test,” he adds. “A scratch on the skin might contain more than enough cells for a micro-analysis.”
Guo’s team has also created metal that reduces the attraction between water molecules and metal molecules, a phenomenon called hydrophobia, which could be used to make metallic surfaces antimicrobial.