Imagine if in order to get apple juice, the whole tree had to be ground up, and then the juice had to be separated from everything else. Well, that's kind of how things currently are with therapeutic plant extracts … but perhaps not for much longer, thanks to a tiny new harvester.
Currently being developed at the Technical University of Denmark, the setup consists of a robotically manipulated microneedle and a microscope camera, both of which are linked to a computer.
The harvesting process begins with the camera scanning a plant's leaf, while that leaf is still on the living plant. A previously trained machine-learning-based algorithm on the computer analyzes the video in real time, identifying any cells which contain the sought-after liquid metabolite – metabolites are chemicals produced by plants, and they're typically contained within the individual cells.
The microneedle is then guided in, piercing the cell and drawing out the metabolite. This process is rapidly repeated on all of the leaves, on multiple plants. In this way, the plants are left alive to continue producing more of the chemicals.
And while such a technique may seem overly meticulous and time-consuming, keep in mind that all of the metabolites will be immediately available, in pure form. By contrast, in traditional methods where entire leaves or plants are ground up and processed, a considerable amount of time, effort and energy goes into separating the metabolites from other materials. Even then, the end product may contain traces of other plant chemicals, plus processing facilities are left with a lot of waste material that has to be disposed of.
"If you want to extract the pure substances, you need to do it cell by cell," says the lead scientist, Assoc. Prof. Kaare Hartvig Jensen. "And when you can do that, as we've shown, you don't have to harvest the plant. Then you can put the little robot on and it can work without damaging the plant."
A paper on the research was recently published in the journal Plant Physiology.
Source: Technical University of Denmark