Aptamer-based smart fertilizer coating and fiber optic sensors for synchronized crop nutrient delivery

Overview

This solution addresses the longstanding inefficiency of conventional fertilizer application, where nutrients are often supplied without regard to actual crop demand, leading to wasted inputs, higher costs for farmers, and environmental harm from nutrient runoff. The core innovation is a smart fertilizer coating embedded with aptamers, which are short, synthetic nucleic acid sequences that bind specific target molecules with high affinity. By detecting root exudates, compounds released by plant roots into the surrounding soil, the coating can release nutrients only when the crop signals a need. The research team is also developing fiber optic sensors capable of tracking these biomarkers in real time across the field, enabling a vision of a connected farm where molecular-level information about crop and soil status drives precise, localized fertilizer management.

Technical specifications

Aptamer selection and engineering:

• Aptamers for L-serine, a root exudate associated with nitrogen uptake in wheat and canola, were identified using SELEX (Systematic Evolution of Ligands by Exponential Enrichment) performed directly in agricultural soil solution
• Selected sequences were converted into a mirror-image (spiegelmer) form to provide nuclease resistance, enabling them to function in the harsh soil environment
• Preliminary data confirm that a fertilizer coated with these aptamers releases its nutrient payload in response to L-serine

Next-generation biomarker targets:

• Future work will apply capture SELEX with stringent counter-selection steps in soil solution to identify aptamers for gamma-Aminobutyric acid (GABA), a root exudate linked to phosphorus demand in corn
• Top candidate sequences will be converted to mirror-image form and validated for binding affinity, target specificity, and nuclease resistance

Fiber optic sensing platform:

• Validated aptamers will be integrated into an aptamer-based fiber optic sensor platform previously demonstrated for biological testing
• Similar fiber sensors have been deployed successfully in soil environments, supporting feasibility for on-farm exudate profiling
• Sensors are intended to track rhizosphere biomarker profiles and inform crop nutrient status in near real time

Potential applications:

• Precision agriculture and smart fertilizer products for wheat, canola, and corn
• Reduced fertilizer waste and lower input costs for growers
• Decreased nutrient runoff and associated environmental impact
• Integration with farm ICT systems for data-driven nutrient management

Technology readiness level

The L-serine aptamer and proof-of-concept coated fertilizer formulation have been demonstrated in laboratory and soil-solution conditions, representing early-to-mid stage development. The GABA aptamer selection, fiber optic sensor adaptation, and field testing of exudate tracking remain future validation activities. Overall, the technology is at an early applied research stage with strong proof-of-concept data supporting the core mechanism but requiring further validation before commercial deployment.