Even if you don't know what 3D microfluidic networks are, that doesn't change the fact that they have some very valuable possible uses. Scientists have now devised a much easier method of making the things, by taking casts of plant roots.
Putting it simply, a 3D microfluidic network is a series of branching micro-scale channels that tunnel through a piece of three-dimensional material. The channels are narrow enough that they're able to disperse various liquids throughout the material via capillary action. No pumping is required.
Among other potential applications, such networks could find use in lab-grown replacement skin or organs, self-healing materials, and soft robotic devices. Due to the fact that microfabricating the tiny channels is such a painstaking task, however, the technology has yet to enter wide use.
With this limitation in mind, Prof. Fujio Tsumori and colleagues from Japan's Kyushu University looked to something that already has the desired structure: plant roots. After all, when it comes down it, roots are essentially just intricate water-transporting structures that branch out through a three-dimensional soil matrix.
The scientists started by creating a soil-substitute growth media made up of silica nanoparticles, hydroxypropyl methyl cellulose resin, and water. Seeds of plants such as radish, white clover, and ryegrass were then placed in that media and left to sprout.
Once the plants had established a good root network, they and the growth media were placed in a kiln and heated to over 1,000 ºC (1,832 ºF). This caused the plant matter to completely decompose, plus it caused the silica particles to melt, merge, and form into glass.
The end result was a transparent slab of glass full of root-shaped microfluidic channels. Those channels ranged in width from 150 micrometers for the main roots, down to approximately 8 micrometers for hairs that branched off of those roots.
Taking the concept a step further, the scientists experimented with growing fungi in the media instead of plants. It was found that the organisms' extremely fine root structure, known as hyphae, formed channels in the glass as narrow as 1 micrometer.
Along with the technology's other potential applications – in which matrices other than glass may be used – it could also simply serve as an easier means of studying the function of plant roots. This could in turn lead to improved methods of growing crops.
"The focus of our lab is biomimetics, where we try to solve engineering problems by looking to nature and artificially replicating such structures," says Tsumori. "And what better example of microfluidics in nature than plant roots and fungal hyphae?".
A paper on the research was recently published in the journal Scientific Reports.
Source: Kyushu University
