First-of-Its-cind Nanosensor enables real-time iron detection in plants

Researchers have developed a near-infrared (NIR) fluorescent nanosensor that can simultaneously detect and distinguish iron forms (Fe(II) and Fe(III)) in living plants.

The title “The Nanosensor for Fe(II) and Fe(III) Nanosensor for Fe(II) enables spatio-temporal sensing in Planta” is published in Nano Letters.

The collaboration includes disruptive and sustainable technology researchers from the Agricultural Accuracy (IRG) of MIT Research Enterprises (SMART) in collaboration with Singapore Mit Alliance for Research and Technology (SMART), Temasek Life Sciences Laboratory (TLL) and Massachusettets Instity of Technology (MIT).

Iron is important for plant health and supports photosynthesis, respiration and enzyme functions. It exists in two main forms: Fe(II) is readily available for absorption and use by plants, and Fe(III) must first be converted to Fe(II) before making it effective for plants to be utilized.

Conventional methods measure only total iron and lack the distinction between these forms. This is an important factor in plant nutrition. The distinction between Fe(II) and Fe(III) provides insight into iron uptake efficiency, helps diagnose defects and toxicity, enables accurate fertilization strategies in agriculture, and improves crop productivity while reducing waste and environmental impact.

This first similar nanosensor by smart researchers allows for non-destructive, real-time monitoring of iron absorption, transport and changes between different forms such as Fe(II) and Fe(III), which provide accurate and detailed observations of iron dynamics.

Its high spatial resolution allows for accurate localization of iron in plant tissues or intracellular compartments, allowing for the measurement of uniform changes in iron levels within plants. These instantaneous changes can tell you how plants deal with nutrients and use them.

Traditional detection methods are either destructive or are limited to a single form of iron. This new technology allows for the diagnosis of defects and optimization of fertilization strategies. Identifying insufficient or excessive iron intake can be adjusted to improve plant health, reduce waste, and support more sustainable agriculture.

The nanosensor was tested with spinach and bokchoy, but it is species-independent and can be applied to a variety of plant species without genetic modification. This ability enhances understanding of iron dynamics in a variety of ecological environments and provides comprehensive insight into plant health and nutritional management.

As a result, it serves as a valuable tool for both basic plant research and agricultural applications, supporting precision nutritional management, reducing fertilizer waste and improving crop health.

“Iron is essential for plant growth and development, but it is difficult to monitor plant levels. This groundbreaking sensor is the first to detect both Fe(II) and Fe(III) in living plants with real-time high-resolution imaging.

“In enabling non-destructive real-time tracking of plant iron speciation, this sensor opens a new pathway to understanding the implications of plant iron metabolism and various iron variations in plants. Such knowledge will help develop customized management approaches to improve crop yields and more cost-effective soil fertilizer strategies.

This study draws on the established expertise in Smart Distap’s plant nanobionics, leveraging the Corona Phase Molecular Recognition (Cophmore) platform pioneered by Smart Distap and MIT’s Strano Lab.

The new nanosensor features single-walled carbon nanotubes (SWNTs) enclosed in a negatively charged fluorescent polymer, forming a helical corona phase structure that forms a different interaction with Fe(II) and Fe(III). When plant tissue is introduced and interacted with iron, the sensor emits a clear NIR fluorescent signal based on iron type, allowing for real-time tracking of iron movement and chemical changes.

Cophmore technology was used to develop highly selective fluorescent responses, allowing for accurate detection of iron oxidation states.

SWNT’s NIR fluorescence offers excellent sensitivity, selectivity, and tissue transparency, making it more effective than traditional fluorescent sensors. This feature allows researchers to track iron movement and chemical changes in real time using NIR imaging.

“The sensor provides a powerful tool to study plant metabolism, nutrient transport and stress responses. It supports the use of optimized fertilizers, reduces cost and environmental impact, and contributes to nutritious crops, better food security and sustainable agricultural practices.”

“This set of sensors will allow plants to access important types of signaling and the critical nutrients they need to make chlorophyll. This new tool will not only help farmers detect malnutrition deficiencies, but also provide access to specific messages within the plant, in paper.

Beyond agriculture, this nanosensor has promising for environmental surveillance, food safety and health sciences, particularly in the study of iron metabolism, iron deficiency and iron-related diseases in humans and animals.

Future research will focus on using this nanosensor to advance basic plant research into iron homeostasis, nutritional signaling and redox dynamics. Efforts are also underway to integrate nanosensors into automated nutrition management systems for hydroponic and soil-based agriculture, expanding their capabilities to detect other essential micronutrients. These advancements aim to increase the sustainability, accuracy and efficiency of agriculture.