How are nanoparticles used?

Introduction: 

Nanoparticles are particles that are between 1 and 100 nanometers (nm) in size. To give you some context, you could fit one million nanoparticles into this full stop here. 

A typical nanoparticle of fertiliser will be between 10-20 nm so you could fit between 50,000 and 100,000 nanoparticles of this size into this full stop. 

You could also fit 100,000 nanoparticles into the width of a human hair. Nanoparticles are incredibly small and it’s a scientific revolution, that we have learnt to manipulate and adapt them to exist in a wide range of beneficial products. The reason they offer exciting advances in horticulture, as well as other industries, is due to their behaviour on this tiny scale. Nanoparticles will behave differently from their larger counterparts with unique physiochemical properties such as size, chemical composition, surface structure, relative surface area, stability and shape.

Some of the areas that nanoparticles are currently used include; automobiles (made lighter), clothing (stain resistance), sunscreen (increased UV protection), surgery (synthetic bones made stronger), mobile phones (lighter materials), glass packaging for drinks (decrease gas escaping) and in sports (durable equipment such as tennis and golf balls). 

What are they doing in horticulture though?

The research in horticulture has been varied and consistent over the past 14 years. The main nanoparticles being tested for horticultural viability include iron (Fe3O4), silica (SiO2), cobalt ferrite (CoFe2O4), titanium oxide (TiO2), zinc oxide (ZnO), copper oxide (CuO) along with gold and silver nanoparticles (Au and Ag). There are many more being investigated but these are the elements with the most amount of research around them.

Iron (Fe3O4) has had a lot of research recently, one study by Zhu et al. (2008), showed that nanoparticles are directly taken up and translocated in pumpkin (Curcurbita maxima) with no toxic effects at concentrations of 0.5 g/L (1)

Silica (SiO2) has had good research done by Slomberg (2012) showing silica nanoparticle phytotoxicity to Arabidopsis thaliana, a popular plant model for plant biology and genetics, no toxicity was found at doses up to1 g/L (2)

Phytonanotechnology advances and advantages 

The benefits of phytonanotechnology are wide and varied according to the research that has been conducted so far. Phytonanotechnology can deliver fertiliser, pesticides and herbicides to targeted sites and can be released on-demand for nutritional needs or protection from pests. This would reduce the requirement for repeated application of fertiliser/pesticide/herbicide, therefore reducing the negative effects on the environment. A recent review of nanotechnologies in plant sciences by Wang et al. (2016) report that phytonanotechnology can: 

  1) Reduce applications of plant-protection products; 

  2) Decrease nutrient losses from fertiliser; 

  3) Increase yields through optimised nutrient management (3). 

The most important aspect for commercial growers is the increased yield due to the lower energy required by the plant to uptake nutrients. The nanoparticles are so small they require very little energy from the plant via passive transport to pull the nutrients into the vascular system. The plant, therefore, has more energy for other processes such as fruit/root/flower formation and production.

  Leaf tissue analysis indicates that one of the benefits of using nanoparticles of iron (Fe3O4), compared to iron chelates, is the increased uptake of other nutrients. The reason is thought to be due to the increased chlorophyll production in the leaf which increases the amount of light harvested and therefore the increased nutritional demand. This was verified by the leaf tissue analysis which saw an increase of nitrogen, phosphorous, potassium, calcium, magnesium and other micro-elements, compared to a control without nanoparticles. 

Observational studies have shown an increase in oil production in tobacco plants when using iron (Fe3O4), although this needs further testing and analysis to confirm findings. Over the coming years, there will undoubtedly be a lot of benefits coming from phytonanotechnology, but there are concerns over the effect on the environment and the living species within it. However, Nottingham Trent University has carried out aquatic ecotoxicology studies with Gammerus pulex (common freshwater shrimp). Results show concentrations up to 40 mg/L of iron and calcium nanoparticles have no detrimental behavioural or toxic effects.

The future of phytonanotechnology

The future for nanotechnology in horticulture is exciting, it can present revolutionary ways of increasing crop yield, health and nutritional content, along with safer methods of applying pesticides and herbicides. 

To conclude, current research on potatoes have shown dramatic increases in nanoparticles of iron, calcium and zinc. This could potentially lead to reductions in diseases such as iron-deficiency anaemia in lower economically developed countries. 

The future for nanotechnology in horticulture (phytonanotechnology) is extremely promising and we’ll hopefully be looking back at this article in a couple of year’s time with a whole host of innovative nano products.

References:

(1) Zhou, H. et al. (2008) Uptake, translocation, and accumulation of manufactured iron oxide nanoparticles by pumpkin plants. J. Environ. Monet. 10, 713-717

(2) Slomberg, D.L and Schoenfisch, M.H. (2012) Silica nanoparticle phytotoxicity to Arabidopsis thaliana. Environ. Sci. Technol. 46, 10247-10254

(3) Wang, P. et al. (2016) Nanotechnology: A new opportunity in plant sciences. Trends in plant science. TRPLSC. 1423, 1-14

If you want the benefits of nano.10⁻⁹'s cutting edge nanotechnology for your plants, explore our products or find your closest retailer below.