Stimuli-responsive star polymer carriers for precision delivery of active ingredients in plants

Overview

Climate extremes such as heat, drought, and salinity increasingly threaten crop yields. This solution offers a precision delivery platform based on core-shell star polymers that encapsulate an active ingredient (AI) and release it only when and where a plant needs it. The polymer shell is engineered to respond to specific plant stress signals, including elevated temperature and reactive oxygen species (ROS) generated under stress. Once applied to foliage, the carriers are taken up into the leaf and release their payload at the targeted site, helping the plant manage stress without significant damage or yield loss. The approach is designed for high-efficiency foliar uptake and can be tuned to target specific plant tissues such as roots, vasculature, or mesophyll.

Technical specifications

• Core-shell star polymer architecture: A nanoscale core encapsulates the active ingredient while a responsive shell controls release.
• Particle size: Approximately 30 nm diameter, supporting efficient foliar uptake and translocation within the plant.
• Temperature-responsive release: A poly(acrylic acid)-block-poly(N-isopropylacrylamide) (PAA-b-PNIPAm) star polymer has demonstrated in vivo release of a model antimicrobial agent above 32 °C but not at 20 °C.
• ROS-responsive release: A proprietary ROS-scavenging shell alters the polymer structure under oxidative stress, triggering AI release and alleviating heat stress responses in tomato plants.
• Tunable targeting: Polymer design can be adjusted to direct carriers to specific plant features such as roots, vasculature, or mesophyll.
• Versatile trigger options: Beyond temperature and ROS, the platform can be adapted to respond to pH, moisture, or other environmental cues depending on the target application.

Technology readiness level

The platform has been validated in vivo in tomato plants, with demonstrated foliar uptake, translocation, and stimuli-triggered release of model active ingredients. Temperature-activated release and ROS-triggered release have both been confirmed in living plants, along with preliminary evidence of stress alleviation. The technology is at an early-to-mid stage of development, ready for collaborative refinement of targets, active ingredients, and trigger conditions, and for further efficacy testing against specific plant stressors such as extreme climates or pests.