In the beginning it was the tree, an immutable symbol of nature, rooted in time and in the cycle of life. Today, it has become something more than a natural organism. At least in laboratories, plants are changing their identity and function by becoming something different – transformed living beings technological platforms.
They call them biohybrid plants: organisms that combine biological elements, those of the same plant, with technological components such as, for example, nanoparticles. In this way, natural functions such as photosynthesis, growth, sensitivity to environmental stimuli are enhanced by engineered elements, without any intervention on the DNA. Therefore no longer “pure” vegetation, but organisms halfway between nature and technology, in whose lifeblood they flow polymersengineered nanoparticles capable of increasing photosynthesis.
Biohybrid plants: enhanced photosynthesis without genetic modification
The conceptual shift is radical: the tree is no longer just an element of the landscape, but also a advanced biological devicea green infrastructure that actively works to produce energy, capture carbon or monitor the environment. From Europe to the United States to Asia, this new discipline of biohybrid greenery is always enriched with new results. And perhaps the most striking one comes from Italy.
A group of scholars led by Manuela Cioccaresearcher in experimental physics at the Faculty of Engineering of Free University of Bolzano – in collaboration with the Faculty of Agricultural Sciences, the Prime research group, the Bruno Kessler Foundation, Eurac Research, the Ludwig-Maximilians-Universität Munich, the Institute of Materials for Electronics and Magnetism (Imem), the Cnr and Elettra Sincrotrone Trieste – managed to create the first completely biohybrid plant with an increased ability to photosynthesize.
«We worked on plants of Arabidopsis thalianaa model species widely used in plant research, and we have chosen nanoparticles as a technological component semiconducting organic polymer (P3HT) already studied for solar cells” explains Ciocca. «We realized that, thanks to their extremely small size – about five hundred times smaller than the diameter of a human hair – these nanoparticles could be absorbed naturally by the roots. For this reason we germinated the seeds in a hydrogel enriched with these nanocomponents, which then entered the root system of the plant and followed the normal internal flows of water and nutrients.”
Nanoparticles as antennas to capture sunlight
In this way they were transported to the leaves and integrated into the biological processes of the shrub without invasive interventions and without altering its DNA. «In leaves, nanoparticles act as tiny antennas which capture green light, a frequency of the spectrum that plants do not normally absorb. It means improving the conversion of solar energy into chemical energy so as to increase the increase of biomass and the absorption of CO2» adds Ciocca. In short, this research demonstrates that plants treated with nanoparticles grow much more than normal and accumulate more biomass. Once the techniques have been validated on the model, we can think about scaling the experiment to other species, grown in greenhouses or in conditions closer to the real ones, with larger sized plants.
Of course, when moving to full scale, additional factors come into play: variable climate conditions, the amount of nanoparticles to be administered to an adult tree, and their life cycle itself. Precisely for this reason we have verified that those used are compatible with the plant and with humans, and that, if they end up in the soil, their life cycle and degradation will have to be carefully studied.
«A truly significant fact is that we managed to insert the nanoparticles through the roots, starting from the seed» continues Ciocca. «But it must also be said that the result was good: we studied different concentrations of polymers, from zero up to one milligram per milliliter, always observing faster growth, up to 45% more growth compared to untreated plants and approx 11% more biomass. By analyzing the roots with the fluorescence microscope, we found the presence of the nanoparticles also in some leaves, where they contribute to the absorption of additional light.”
From energy to monitoring: applications of plant electronics
There are many possible applications of biohybrid plants. «One of the most promising concerns the capture of CO2 and biomass production. Another is that of the generation of electricity, through the same principle of photovoltaic panels» explains Ciocca.
«As far as agri-food is concerned, it is still in its embryonic phase: there are no clear guidelines on toxicity, but the advantage of our technology is that it does not modify the genetics of the plant. The nanoparticles integrate spontaneously and the plant is positively enhanced. This opens interesting perspectives for thesustainable agriculture: if plants grow more and accumulate greater biomass, it is possible to increase the productivity of crops in a natural way, reducing waste and improving the efficiency of plantations.”
The Italian experiment is just one part of a global scientific movement. There are several laboratories in the world that are studied nanobionic plants capable of increasing photosynthesis thanks to the integration of nanoparticles. A first line concerns the biohybrid microalgaein which single-celled photosynthetic organisms are supplemented with metallic or polymeric nanoparticles to enhance light absorption and electron transfer in photosynthetic processes. This allows us to increase the production of natural pigments (such as carotenoids and modified chlorophylls) and metabolites useful for the pharmaceutical and food industries, without intervening on DNA but exploiting the physical interaction between inorganic materials and biological structures. A second trend, developed especially in Scandinavia, to Linköping Universityaims to make plant roots conductive by integrating electronic organic polymers directly into plant tissues.
The future of living sensors and biological infrastructures
The shrubs themselves favor the formation of electrically conductive structures along the root system, transforming them into a sort of biological capacitor. These “electronic” roots do not replace the vital function of the plant, but support it, transforming the plant tissue into a functional material that combines metabolism and electrical conduction.
A third strand concerns green as living environmental sensor: the integration of nanomaterials (such as carbon nanotubes or conductive particles) in leaf or vascular tissues allows us to read the electrical and chemical signals that the organism naturally produces when it undergoes water stress, variations in salinity, the presence of heavy metals or air pollutants. These indications can be collected and transmitted to digital devices, creating networks of environmental monitoring based on live “sensors” that react in real time to soil and air conditions.
In all these cases, the key element is not genetic modification, but the construction of hybrid systems in which biological functions are amplified or made readable thanks to nanostructured materials, giving rise to new forms of “plant electronics” and energy biomanufacturing and sensorial. In this scenario, plants stop being just passive organisms and become active biological infrastructures: sensors, energy accumulators, environmental monitoring platforms.
The frontier of plant bio-nanotechnologies does not promise science fiction “superplants” capable of solving our energy problems, but organisms capable of communicating with digital systems and the environment that surrounds them, making processes invisible today invisible. If this research manages to leave the laboratories without altering the ecological balance, the future ofelectronics it could thus literally sprout from the ground.
