Plastic films that mimic the self-folding movements of plants may hold the key to developing a new generation of microfluidic devices. The new films fold when they respond to stimuli and they can also organize into complex three-dimensional structures.
"The self-folding films can be used to encapsulate cells because cells remain encapsulated in the self-folded capsule but the chemicals can freely diffuse to the cells since the wall are not tightly closed," Dr. Leonid Ionov, a German researcher, told Plastics Today. "Or they can be used to build channels for microfluidic devices."
At the heart of the invention are two polymers possessing different properties.
"In particular we work with thermoresponsive polymers for fast reversible encapsulation of cells and biodegradable polymers for encapsulation and slow release of cells," Ionov said. The two-structure film can bend and form a tube or capsule because they do not expand at equal rates.
It's possible to design 3D micro-structures with patterned inner and outer walls. Structures ranging in size from hundreds of nanometers to centimeters is possible.
He said there are several different polymers he may work with that are sensitive to various external signals, including physiological ranges of pH and temperature as well as polymers sensitive to biochemical processes. There are also several biocompatible and biodegradable polymers.
Ionov is a Group Leader at the Leibniz Institute of Polymer Research in Dresden, Germany. The long-term vision for his group's research is to develop smart biomaterials that can be used for the regeneration of blood vessels, bones, cardiac tissue and nerves.