Researchers from the University of Glasgow have developed a way to grow microfluidic systems from materials that can function as sensors and catalysts in chemical reactions. The technology, that uses electric fields to guide the formation of the tubular structures, should help in developing smaller and more complicated labs-on-a-chip devices for all sorts of medical applications.
From MIT Technology Review:
The inorganic crystals that the researchers use belong to a class of chemicals known as polyoxometalates. These negatively charged clusters of metal and oxygen atoms are excellent catalysts for many different reactions in the chemical industry. They are also good at sensing and adsorbing gases, and are used to remove toxic compounds like nitrogen oxides and sulphur dioxide from flue-gas streams. By using different metal atoms, researchers can create polyoxometalates with various chemical properties. “Polyoxometalates have large structural diversity and versatility, as well as a lot of options to modify physical and chemical behavior,” says Paul Kogerler, a professor of chemistry at RWTH Aachen University, in Germany.
To create their microtubes, the Glasgow researchers use crystals containing tungsten. When they put these negatively charged metal-oxide crystals in water and add positively charged fluorescent molecules, the crystals start to sprout tubes in just a few seconds.
Cronin explains that the positive and negative molecules join up to form a membrane on the crystal’s surface. The pressure inside this membrane builds up until it ruptures and the metal-oxide material inside pours out in a jet. As it streams out, it automatically starts to form a hollow tube through which more and more material can flow out. The tube grows until all that’s left of the crystal is the hollow membrane shell.