A team of researchers from the Federal University of São Carlos (UFSCar) in Brazil has developed an approach for turning fallen leaves into sensors.
To accomplish this, the team reportedly developed an approach for laser-printing electrochemical sensors on the surface of the leaves. Using a carbon dioxide (CO2) laser, the team printed the desired design on the leaf via pyrolysis and carbonization.
Through this process, an electrochemical sensor was created that can be used for determining levels of dopamine and paracetamol.
Bruno Janegitz/Federal University of São Carlos (UFSCar)Bruno Janegitz/Federal University of São Carlos (UFSCar)
“A drop of the solution containing one of these compounds is placed on the sensor, and the potentiostat to which it’s coupled displays the concentration,” the researchers added. A laser beam is used to burn a leaf via pyrolysis, which converts the cellulose in the leaf to graphite that is subsequently printed onto the leaf in a shape that can operate as a sensor.
To achieve the desired results, different parameters of the CO2 laser were modified — for instance, the laser power, pyrolysis scan rate and scan gap.
“The sensors were characterized by morphological and physicochemical methods, permitting exhaustive exploration of the novel carbonized surface generated on the leaves,” the team added.
In the lab, tests performed on the sensors involved the detection of dopamine and paracetamol in biological and pharmaceutical samples. For dopamine, the system proved efficient in a linear range of 10 micromoles to 1,200 micromoles per liter, with a reported detection limit of 1.1 micromoles per liter. Meanwhile, for paracetamol, the system reportedly proved efficient in a linear range of 5 micromoles to 100 micromoles per liter, with a reported detection limit of 0.76.
The researchers concluded that the electrochemical sensors derived from fallen tree leaves demonstrated satisfactory analytical performance and notable reproducibility.

An article detailing the team’s findings, “Green Fabrication and Analytical Application of Disposable Carbon Electrodes Made from Fallen Tree Leaves Using a CO2 Laser” appears in the Sustainable Chemistry and Engineering journal.

To contact the author of this article, email mdonlon@globalspec.com