TIPWG newsletter March/April: Could the future be nano?

When it comes to “scientific buzzwords”, “nano” has to be my prefix of choice – at least for the last 5-10 years! The world, it seems, has gone crazy for nano. From nano-sim cards in phones to the nano-particles in my face cream that promise eternal youth, the future it appears is nano. So, what does this mean for forestry?

In an article featured in AgriBusiness Global by AZoNano, a leading online publication for the nano-community – yes there is even a nano-community now – nanotechnology has already “contributed immensely to sustainable agriculture by enhancing crop production and restoring and improving soil quality.” With the technology already being applied to various aspects of agriculture, from pesticide delivery and slow-release biofertilisers to crop development and the detection of biotic and abiotic stressors. In a recent scientific paper in the Journal of Chemical Studies titled Nanotechnology in Agriculture: A review, the authors Verma, Bodh and Thakur state, “nanotechnology has the potential to revolutionize agricultural systems, biomedicines, environmental engineering, safety and security of water resources, energy conversion and numerous other areas” (Verma et al.2019). It almost sounds too good to be true, which is why it should be noted that their enthusiasm for the technology comes with the warning, “there is an urgent need for informed public debate on nanotechnology in agriculture and food… …nanotechnology can be applied in all aspects of the food chain, both for improving food safety and quality control and as novel ingredients and additives, which may lead to unforeseen health risks.”

Before we can consider the potential health and environmental impact of this technology, the ethics surrounding its use and how it should be regulated in the future, it is important to understand what the technology is and its potential applications in agriculture.

According the Verma et al. (2019), “nanotechnology is the art and science of manipulating and rearranging individual atoms and molecules at nanoscale to create useful materials, devices and systems.” It involves working with the smallest possible particles which raise hopes for improving agricultural productivity through encountering problems unsolved conventionally (Sing and Rattanpal, 2014). As a result, nanotechnology has the potential to increase the efficiency and quality of agricultural production, as well as introduce new functionality (value-added products) for food, fibre and agricultural commodities. Certainly, this has already been experienced in the forestry value chain with monumental advances that have been as a result of nano-cellulose research and development. So, what about the agricultural production side, how can and is nanotechnology revolutionizing the sector?

Nanotechnology: new varieties and seed science

Nano-capsules could be the ‘silver bullets’ scientists have been waiting for to deliver DNA or chemicals to isolated plant cells. In Verma et al. (2019) paper, they discuss a study done by Torney et al. (2007) which exploits a 3 nm mesoporous silica nanoparticle to deliver genes through cell walls in a clear-cut and controlled manner, without any toxic side effects. This technology has already been used to establish DNA in both tobacco and corn plants.

Carbon nanotubules (CNT) have improved tomato germination, allowing better permeation of moisture by penetrating the seed coat and serving as new pores for water permeation.

Nanotechnology: soil nutrient levels

Nanotechnology offers an opportunity to tackle nutrient deficiency in the soil through the slow, controlled release of nano-based fertiliser formations. Verma et al (2019) cite the work of Tarfdar (2012), who has shown significant increases in yield through foliar nanoparticle fertiliser applications. With research showing fertilisers encapsulated in nanoparticles increase the uptake of nutrients (Tarfda et al, 2012), the focus has now turned to developing nano-composites to supply all the required essential nutrients in a suitable proportion through a smart delivery system, with the release triggered by environmental conditions or over a desired specific time.

Nanotechnology: pesticides

We live in a world where pest control is becoming increasingly important in boosting productivity to feed an ever-expanding global population, but at the same time, we are becoming more aware of the potential adverse social and environmental impacts of pesticide use.

Nanotechnology provides an opportunity to develop a target-specific insecticide/herbicide/fungicide molecule encapsulated within nanoparticles that has the potential to reduce the risk to non-targets and the accumulation of residues in the soil. Nanoencapsulation, the sealing of active ingredients within a thin-walled sac or shell, enables the controlled release of the active ingredient over time or in response to environmental stimuli, which has the potential to decrease the amount of pesticide input. The use of nano-pesticides also reduces the rate of application because the quantity of the product is around 10-15 times smaller than applied in classical formulations. A good example of this is clay nanotubes, which carry pesticides at low cost, for extended-release and better contact with plants. It is suggested, they will reduce the amount of pesticides by 70-80%, thereby reducing both cost and environmental impact.

Nanotechnology: plant health

An interesting area of bio-nanotechnology research is in the development of nano-based diagnostic kits. These detect and utilize biomarkers, such as protein production, to accurately indicate the disease stage.

Then there are the nano-particles being used to control plant diseases, an area of science that has astounded scientists as a result of common materials showing dramatically different properties when used at a nano-level. Nano-sized silver particles have been shown to work as antimicrobial agents, inhibiting the action of micro-organisms in several ways – including changes in routine functions of the plasma membrane (Pal et al, 2007) and preventing the expression of ATP production associated proteins (Yamanka et al 2005). With technological advances making the production of nano-size silver more common, it has become more economically viable and Verma et al. (2019) suggest a relatively safer alternative to commercially used fungicides. Nano forms of zinc oxide and silica are showing antiviral properties, while nickel ferrite and copper exhibit antifungal properties.

Nanotechnology: Biosensors

Another interesting area of research and development is the production of nanotechnology-based biosensors that enable researchers to study plant chemical pathways in real-time. Hormones such as auxin, responsible for root growth and seedling establishment, are being studied by scientists at Purdue University. At Purdue, scientists have developed a nano-sensor that reacts with the hormone and oscillates. The oscillations can be monitored and recorded to provide auxin concentration readings. Other uses for this technology include the detection of pathogenic micro-organisms, antibiotic resistance, as well as the presence of toxins and heavy metals.

Conclusion

The field of nanotechnology is an exciting one and something our industry has already benefitted greatly from. The exponential increase in nanotechnology applications, research and development suggest the future is nano and that this technology will play a vital role in the development of the agricultural sector. However, with every innovation, the potential risks associated with the technology needs to be assessed, mitigated and properly regulated. The importance of this is not solely to ensure the environment and our health is protected from any unforeseen implications of the technology, but also to ensure social acceptance of the technology. Nanotechnology, like genetically modified organisms (GMO), has the potential to help society address several challenges we currently face. We must learn from the lessons of GMOs, which have been socially rejected in many countries, to ensure nanotechnology does not follow the same path.

REFERENCES
Pas S., Tak YK and Song JM. (2007). Does the antibacterial activity of silver nanoparticles depend on the shape of the nanoparticle? A study of the gram-negative bacterium E.coli. Applied Environmental Microbiology. 73:1712-1720.

Sing G and Rattanpak HS. (2014). Use of nanotechnology in horticulture: A review. International Journal of Agriculture, Science and Veterinary Medicine. 2

Tarafdar JC. (2012) Perspectives of nanotechnology applications for crop production. NAAS News. 12:8-11.

Tarafdar JC., Agrawal A., Raliya R., Kumar P., Burman U., and Kaul RK. (2012) ZnO nanoparticles induced synthesis of polysaccharides and phosphatases by Aspergillus fungi. Advanced Science, Engineering and Medicine. 4:1-5

Verma P., Bodh S. and Thakur S. (2019). Nanotechnology in agriculture: A review. International Journal of Chemical Studies. 7(4): 488-491

Yamanka M., Hara K. and Kudo J. (2005) Bactericidal actions of silver ions solution in E.coli studying by energy filtering transmission electron microscopy and proteomic analysis. Applied Environmental Microbiology. 71: 7589-7593.

Photo by Aegon Boucicault on Unsplash

/ Pesticide interest piece