A Prototypical Conjugated Polymer Regulating Signaling in Plants

Abstract

The use of nanomaterials has been very recently introduced in plant biotechnologies, for both the monitoring and the enhancement of plants functions. Several functional interfaces between living plants and nanotechnology have been successfully reported for diverse applications, from sensing to photosynthesis and energy production and from modulation of physiological activity to controlled delivery of chemicals. In this work, a photoactive, biohybrid interface based on a prototypical semiconducting polymer, sensitive to green light, and Arabidopsis thaliana plants is reported. Optical excitation of polymer beads is shown to deterministically regulate the Arabidopsis stomatal aperture, the leaf pores which regulate the plant carbon dioxide uptake, oxygen release, and transpiration processes. Moreover, it is observed that excitation of bio‐polymer hybrid interfaces optically modulates the cytosolic calcium ions concentration, which is involved, as a second messenger, in the regulation of stomatal movements. The results support the possibility to employ light‐responsive organic materials to regulate on demand the physiological activity of plant systems, in a drug‐free, touchless, and easily controllable way. When transferred to the field, this strategy may represent an innovative approach to optimize the exchange of gases and water loss of plants, and to improve the plant resilience toward environmental constraints.

Mixed Ionic–Electronic Conduction, a Multifunctional Property in Organic Conductors

“…Indeed, traditional hydrophobic organic electronic materials have recently emerged as opto-bio actuators in both in vitro and in vivo applications, where photoexcitation effectively modulates the biological activity of cells and tissues. [53][54][55][56] While the physical and physiological mechanisms of stimulation in these systems are often not fully elucidated, [57,58] the phototransduction mechanism is generally associated with thermal effects, charge-transfer reactions (Faradaic coupling), photochemical phenomena, and capacitive coupling at the biotic/abiotic interfaces. [59,60] In fact, a common strategy to increase photostimulation relies on materials configurations that maximize the effective electrochemical surface, such as nanostructured planar interfaces, [61,62] nanoparticles, [63] or hierarchical nanocrystals.…”

Plant Bioelectronics and Biohybrids: The Growing Contribution of Organic Electronic and Carbon-Based Materials

“…Recently, the Antognazza group demonstrated the use of poly(3-hexylthiophene (P3HT) nanoparticles for light-induced modulation of stomata aperture. 141 Leaf epidermal strips of Arabidopsis thaliana were incubated in a P3HT nanoparticles solution. The nanoparticles were not internalized by the leaf tissue or entered the cytosol of guard cells but remained in the extracellular bath.…”

“…Conjugated polymer nanoparticles were also used as light transduction units for plant physiology modulation. Recently, the Antognazza group demonstrated the use of poly­(3-hexylthiophene (P3HT) nanoparticles for light-induced modulation of stomata aperture . Leaf epidermal strips of Arabidopsis thaliana were incubated in a P3HT nanoparticles solution.…”

Organic Semiconductor–Organism Interfaces for Augmenting Natural and Artificial Photosynthesis

“…Antognazza et al constructed a conjugated polymer–stomatal interface and realized the regulation of stomatal aperture and cytosolic calcium ion concentration . Berggren et al.…”

“…Antognazza et al constructed a conjugated polymer−stomatal interface and realized the regulation of stomatal aperture and cytosolic calcium ion concentration. 34 Berggren et al took advantage of the upward transport effect of vessel elements to absorb and transport self-doped anionic polythiophene derivatives, poly(4-((2,3-dihydrothieno [3,4b] [1,4]dioxin-2-yl)methoxy)butane-1-sulfonic acid) (PEDOT-S:H), to the xylem channels of rose, where PEDOT-S:H formed uniform and longrange hydrogel wires. 35 PEDOT-S:H wires, serving as source, drain, and transistor channel, were assembled into organic electrochemical transistors (OECTs) with surrounding tissues and extracellular medium, which exhibited excellent output performance.…”