Adding nanoparticles to lettuce seeds to help them germinate, and using neutron imaging to find out why
17 Aug 2026 - Rosie de Laune
A team from Universiti Teknologi MARA, Malaysia, Tokyo University of Agriculture and Technology and ISIS used the IMAT beamline at ISIS to study lettuce seeds that had been pre-treated with chitosan-stabilised iron oxide nanoparticles (CS-FeNPs) to improve their water uptake. Neutron imaging enabled them to study the seeds during germination and determine how the nanoparticles improve hydration.
Seed germination is highly sensitive to how much water is available. With an increasing global population causing higher demand for food, and hotter temperatures leading to reduced water availability, improving germination success when limited water is available is vital for future food security.
One promising approach is seed nano-priming, in which seeds are pre-treated with engineered nanoparticles to improve germination, nutrient uptake, and stress resilience. Iron oxide nanoparticles (FeNPs) show several promising properties but suffer from poor stability under certain conditions. Chitosan is biodegradable and sourced from chitin-rich agricultural waste streams and can be added as a stabiliser.
Chitosan-stabilised FeNPs (CS-FeNPs) show greater biological efficacy, but the mechanistic pathways relating to how nanoparticle formulations influence internal seed hydration are still not well understood.
To address this, a group from Universiti Teknologi MARA, Malaysia, and Tokyo University of Agriculture and Technology came to ISIS to use neutron computed tomography (NCT) to study the germination of lettuce seeds after treatment with CS-FeNPs. NCT is a non-destructive, three-dimensional imaging technique that is uniquely sensitive to hydrogen, the principal constituent of the water that is so crucial to these seeds during germination.
To enhance the neutron imaging contrast, the seeds were watered with D2O during germination, and seeds of varying germination times were imaged using NCT. The group were able to visualise the internal water transport during germination, achieving a spatial resolution that was sufficient to capture tissue-level hydration dynamics.
They saw enhanced water uptake in the nano-primed seeds, because the chitosan coating enhances water mobility through the electro-steric stabilisation of the nanoparticles, and because of the chitosan’s intrinsic ability to modulate water dynamics at the seed surface. These results highlight that CS-FeNPs not only outperform FeNPs in promoting early growth but do so through a fundamentally distinct hydration-mediated mechanism, with NCT providing in situ confirmation.
NCT provided direct, spatially resolved evidence that CS-FeNP priming altered the internal water distribution during germination, and gives us direct structural evidence of hydration-guided germination.
Noor Fitrah Abu Bakar, Universiti Teknologi MARA
“NCT provided direct, spatially resolved evidence that CS-FeNP priming altered the internal water distribution during germination, and gives us direct structural evidence of hydration-guided germination,” says study author Noor Fitrah Abu Bakar, from Universiti Teknologi MARA. “This links nanoparticle formulation to real-time physiological outcomes in intact biological systems.”
Overall, this work establishes NCT as a quantitative, non-destructive tool for dynamic water imaging in biological systems, highlighting its potential for investigating biological interactions where hydrogen-sensitive contrast is critical.
The full paper can be found at DOI: 10.1016/j.apradiso.2026.112637
