Smart release technology for improving fertilizer efficiency

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1 Smart release technology for improving fertilizer efficiency Emily Mastronardi, Dr. Carlos Monreal, Dr. Maria C. DeRosa AAFC-ECORC and Carleton University

2 Why create nanofertilizers in Canada? Canada has a large area of cultivated land Leader in fertilizer production By 2050 Increased demand for fertilizer for food, biomass, biofuels Population to increase from 7 B to 9.8 B people Close to 1 B people undernourished Increase food production 70% for > 2 B more people Major economic and environmental implications 30 to 50% efficiency N losses to the environment 2

Fertilizer runoff can cause algal blooms Algal

3 Fertilizer runoff can cause algal blooms Algal blooms deplete oxygen and secrete a neurotoxin, affecting wildlife Targeted release problem Need to increase fertilizer efficiency 3

4 The challenge: increase NUE Synchronize the application of nutrients with crop uptake 4

5 How do we synchronize nutrient release with uptake? 1. Use acquired knowledge to propose and test new hypothesis 2. Create new knowledge on soil-crop ecology 3. Develop new tools and devices using nanotechnology (i.e. DNA aptamers) 4. Integrate knowledge and nano-tools into novel Intelligent Nanofertilizers 5

6 Interactions and communication in plant-soil systems Last century the 1950s and 60 s Crop roots emit organic materials (Rovira et al. 1966) Different crop root species emit different types of organic compounds (Rovira, 1956) Root emissions consist of sugars, amino acids, vitamins, organic acids (Rovira, 1966) Root emissions from cereals are similar, but different from exudates from tomato and red peppers (Vancura and Hovadik, 1965) 6

7 Root exudation and nutrient uptake Early this century Root emissions control nutrient uptake and soil microbial growth and function (Dakora and Phillips 2002) Increased root emissions occur in response to decreased nitrate (NO 3 ) availability (Darwent et al. 2003) The rate of nitrogen uptake in Prairie crops is associated with growth stage (Malhi et al. 2006) 7

8 Utilizing nanotechnology Plant pores are nano-sized Use nanotechnology to increase NUE 8 DeRosa, et. al. Nanotechnology in Fertilizers Nature Nano. 2010, 5, 91.

10 Testing the central hypothesis Multi-disciplinary approach mixing soil-plant ecology and nanotechnology New knowledge of soil-plant ecology: Identification of root exudates associated with soil N mineralization and its uptake by crops Development of biosensors to detect root exudates (for on-demand release) Development of coating polymers and 3-D nanocoating tools Intelligent nano-fertilizer prototypes and products 10

11 Intelligent nanofertilizer proposed technology 11

Intelligent nanofertilizer proposed technology Urea Biosensor with polymer layers (10 to 100 nm) - 1 nanometer = 10-9 m or billionth of a meter Root exudates The biosensor will be incorporated into a

12 Intelligent nanofertilizer proposed technology Urea Biosensor with polymer layers (10 to 100 nm) - 1 nanometer = 10-9 m or billionth of a meter Root exudates The biosensor will be incorporated into a very thin polymer film. Interaction of the biosensor with the desired root exudate changes the permeability of the polymer film: release of urea-n according to crop demand. Immediate goals: 1. Identify important root exudates 2. Develop biosensor to detect them 12

Identifying exudates important for nitrogen uptake - Crops: wheat and canola (each

1) Soil alone 2) Soil + crop 3) Soils + crop (no crop) (0 N) (100 kg urea-n/ha) -

biomass, crop N uptake and yield, C and N flows in rhizosphere using 13 C and 15 N -

13 Identifying exudates important for nitrogen uptake - Crops: wheat and canola (each grown twice) - Soil: Manotick, uncropped for 15 years, 0-20 com depth - Treatments: 1) Soil alone 2) Soil + crop 3) Soils + crop (no crop) (0 N) (100 kg urea-n/ha) - Weekly characterizations: soil solution composition, enzyme activities, microbial biomass, crop N uptake and yield, C and N flows in rhizosphere using 13 C and 15 N - Soil solution - Four techniques of Mass Spectrometry: - Py-FIMS, GC-MS, ESI-MS, LC-ESI-MS/MS 13

Identifying exudates important for nitrogen uptake kg N/ha/d 3 leafs unfolded Found increased N uptake during specific growth periods 2 1 57 278 IF031 4 leaves unfolded, September 30 294 306

14 Identifying exudates important for nitrogen uptake kg N/ha/d 3 leafs unfolded Found increased N uptake during specific growth periods IF031 4 leaves unfolded, September Intensity Temperature in C Used Mass Spectrometry to identify exudates in the soil during this time m / z 14

15 Identifying exudates important for nitrogen uptake Found exudates that track with nitrogen uptake Wheat Canola 15

16 Identifying exudates important for nitrogen uptake Identified 12 chemical signals closely associated with crop N uptake Some signals are specific to wheat and others to canola Potential for designing crop specific fertilizer 16

17 Nano-biosensors Aptamers Single-stranded oligonucleotides Synthesized chemically Fold into 3D nanoscale shapes capable of binding targets Can distinguish small structural differences 17

18 Aptamers selected through iterative process called SELEX Systematic Evolution of Ligands by EXponential enrichment In vitro technique beginning with random DNA sequences Each round increases affinity of pool for the target Pool is cloned and sequenced Control over selection conditions 18

aptamers can act as the negative layer, making the film

19 Layer-by-layer deposition creates smart aptamer films Alternating layers of positive/negative polyelectrolytes creates a film DNA aptamers can act as the negative layer, making the film responsive 19 Sultan, DeRosa, Monreal Biomacromolecules 2009, 10,

20 Embedded aptamers retain binding and increase permeability Aptamer films show higher target binding and higher permeability than control films 20 Mastronardi et.al. (2015) Methods

21 Layer-by-layer deposition creates smart aptamer microcapsules A) Aptamer-target binding leads to change in permeability and release of payload B) Aptamers act as structural support for microcapsule, and target-binding leads to microcapsule rupture Sultan and DeRosa. (2011). Small, 7: Zhang et.al. (2013) ACS App. Mater. Interfaces, 3: Mastronardi et.al. (2014) Sensors, 14:

22 Aptamer microcapsules maintain target binding Fluorescence co-localization study A and D: Fluorescein channel (Aptamer) B and E: Rhodamine channel (Target) C and F: Overlaid signals - binding 22 Sultan and DeRosa. (2011). Small, 7:

Aptamer capsules specific for a root exudate show increased dye permeability A Target molecule Diffusion coefficient (µm 2 /s) Aptamer film with Exudate 0.0113± 0.

23 Aptamer capsules specific for a root exudate show increased dye permeability A Target molecule Diffusion coefficient (µm 2 /s) Aptamer film with Exudate ± Aptamer film with Negative ± control Sultan and DeRosa. (2011). Small, 7: Zhang et.al. (2013) ACS App. Mater. Interfaces, 3:

24 Aptamer capsules for exudate-triggered delivery Microcapsules show target-triggered morphology changes Morphology unaffected without target Rupture controlled by target concentration and time 24 Zhang et.al. (2013) ACS App. Mater. Interfaces, 3:

25 Concluding remarks Developing nanofertilizers requires a multidisciplinary approach Chemical signals (exudates) important for nitrogen uptake have been identified in wheat and canola Biosensors (Aptamers) have been developed for these exudates Early prototypes of smart-release nanobiosensors have been developed for use with intelligent fertilizers 25

26 Acknowledgements Organizations The Alberta Innovations Bio Solutions and AAFC for providing financial support Grain Growers of Canada, Canola Council of Canada and Agrium Inc. La Coop Fédérée The DeRosa lab Carleton University Department of Chemistry The Monreal lab Agriculture and Agri-Food Canada ECORC 26

What is bionanotechnology?

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