N March 2025, Dr Cong Vu, CEO and founder of NanoSoils Bio, filed three patents related to silica nanoparticle (SiNP) processing and manufacture, overcoming the barriers to scaling up and commercialising the technology in agriculture.
Cong began working with nanoparticles in medicine as a means to deliver anti-cancer drugs directly to cancer cells without affecting healthy cells. In the summer of 2019–20, he shifted his attention from nano-medicine to nanoagrichemicals, where there is opportunity to deliver pesticides and nutrients to crop plant cells efficiently.
In 2023, Cong won ABARE’s Science and Innovation Award for Young People in Agriculture, Fisheries and Forestry. His CRDC-supported research for the award program involved testing the potential of silica nanoparticle technology to fortify cotton against drought stress. Drought stress is responsible for 67 per cent of cotton lint yield losses in the Australian industry.
Cong’s expertise lies in producing nanoparticles with different shapes and sizes and studying the properties and potential uses of these particles. Although there are many materials that can be used to create nanoparticles, his work in medicine and agriculture has centred on silica-based nanoparticles. Silica (Si) is the most abundant element in the Earth’s crust, held mainly as quartz crystals in rocks and in silica sand and lump silica (e.g. quartzite) deposits. However, plant-available monosilicic acid is scarce in agricultural soils. Monosilicic acid (MSA) is also known as orthosilicic acid and has the chemical
composition Si(OH)4,
While applications of bulk elemental silica fertilisers are considered relatively ineffective in agriculture, silica nanoparticles (SiNP) can enter plants and the silica is released in plant-available form (monosilicic acid) in the cells, stimulating a hormonal response for increased root development.
In plants, silica is necessary for cell wall strength. Elemental silica needs to be dissolved to be available to plants, however the silica bond is very strong and difficult to break. Cong has developed a new class of silica nanoparticles that dissolve in both acidic (pH<4) and alkaline (pH>10) environments,
meaning that elemental silica can be applied in nanoparticle form, which then dissolves within the plant to form monosilicic acid. This process is NanoSoils Bio’s recently patented innovation.
Cong put these SiNP to the test on cotton seeds to see if the nanoparticle treatment could support root growth in low soil moisture (drought) conditions.
After initial testing in the laboratory for germination rates under drought stress and to identify the optimal ratio of SiNP to seed, Cong went on to pot experiments in the glasshouse
In the glasshouse, pots were sown with cotton seed coated with nanoparticles (SiNP treatment) and cotton seed without nanoparticles (control). The pots had three different initial soil moisture levels – 100 per cent, 90 per cent and 80 percent. The pots were watered once a week, and the plants were harvested after six weeks.
When SiNP-treated and control plants were fully watered (100 per cent), there was no discernable difference in cotton seedling root development. However, when the soil moisture was reduced to 90 per cent and 80 per cent, the roots of seedlings from the SiNP-treated seeds grew longer than the control. The mass of the roots produced in the 90 per cent and 80 per cent soil moisture treatments were almost the same.
The mechanism by which silica nanoparticles influence cotton roots under drought stress is unclear. Further investigation into the mechanism is required, along with trials to measure the effect of SiNP treatments throughout the crop growing period under different levels of moisture stress.
Cong believes that SiNP could deliver as much as a five per cent reduction in water use in a cotton cropping season. He is also keen to learn more about the value of improved silica nutrition on the uptake of other fertilisers from the soil and enhanced disease resistance. He says the SiNP can also be used to deliver insecticide and fungicide to protect the seeds and enhance early crop vigour. Delivering pesticides using SiNP in seed coatings could result in a reduction in pesticide used at planting.
DELIVERING MORE THAN ELEMENTAL SILICA
Silica (including silicon dioxide and sodium silicate) has been widely used as a fertiliser and bio-stimulant for plants. The benefits associated with silica fertiliser include increased plant cell wall strength, increased vigour and stress resistance, improved crop quality, and increased root development and nutrient uptake.
Silican nanoparticles (SiNP) have attracted attention for agricultural uses due to their unique properties, including their solubility, considerable specific surface area, compatibility with living organisms, and role in essential biological interactions.
These tiny silica particles can enter the cell structure, resulting in robust plant structures that can deter pathogens and insect pests, as well as forming larger root systems that can access more water and nutrients from the soil.
In addition to the beneficial effect of the silica element on plants, nanoparticles can also be used as carriers for other molecules. In medicine, they are used to carry cancer treatment drugs, and in agriculture, there is potential for them to carry insecticides, fungicides and herbicides. This is an area of extensive and intense research around the globe.
For example, Fusarium wilt (caused by Fusarium oxysporum) is almost impossible to eradicate from the soil and is highly detrimental to high-value crops, such as cotton and tomato. Greenhouse trials using fungicide-loaded SiNP controlled. Fusarium crown and root rot in tomato plants four times more effectively than conventional fungicide treatment.
Cong says that studying how plant cells absorb SiNP at cellular or subcellular levels will provide information about the potential adverse effects of nanoparticles on plants and support the design of safer nano-agrochemicals.
SiNP can be applied to seeds, soil or crop leaves at much lower rates than bulk silica fertilisers. They are readily absorbed through the seed coat, roots or leaves and translocated within the plant.
There are potential risks to human health, mainly from inhaling rather than from ingesting nanoparticles. This is one reason why the technology is being tested first with seed coating application.
Read more about Dr Vu’s research:
www.nature.com/articles/s41467-025-57650-8
WHAT ARE NANOPARTICLES?
A nanoparticle is defined as a submicroscopic unit within the size range of 1 to 100 nanometres (nm), where 1 nm is 1 billionth of a metre. For comparison, atomic bond lengths are reached at 0.1 nm.
Nanoparticles are a naturally occurring phenomenon in the environment. For example, they occur in vast volumes in aerosol salt from the ocean, smoke from volcanoes and fires, dust from deserts and fields, and hydrocarbon compounds
such as terpenes emitted by trees.
There are three primary and interrelated physical properties of nanoparticles. First, they are highly mobile in the free state (e.g. a 10-nm-diameter silica nanosphere has a sedimentation rate under gravity of 0.01 mm/day in water). Second, they have enormous specific surface areas. For example, a standard teaspoon, of 10-nm-diameter silica nanospheres has a surface area greater than a dozen doubles-sized tennis courts. In this example, 20 per cent of all the atoms in each nanosphere will be located at the surface. Third, they may exhibit ‘quantum effects’.
Manufactured nanoparticles have a vast range of compositions, depending on their intended use or product requirement. They can be classified in various ways according to their size, shape, and material properties. There are organic and inorganic nanoparticles. Carbon-based, ceramic, semiconducting and polymeric nanoparticles.
There are ‘hard’ and ‘soft’ nanoparticles.
In terms of improved water use efficiency, Cong set out to invent a nanoparticle formulation that could underpin the early development of a robust root system and stretch the first in-crop irrigation to a later date. With a strong and welldeveloped root system, the cotton plants are better able to forage for soil moisture and fertiliser.
Over the past seven years, Cong has synthesised more than 100 types of silica nanoparticles and can control the particle size (30 nm to 2 µm) and shape (spherical to rodlike). His glasshouse trials validated the proof of concept and established that six grams of SiNP per 1 kg of seeds had the best effect on seed germination and plant development. At this application rate, it costs between $2 and $5 to treat 1 kg of cotton seed. This cost is likely to decrease when the SiNP production is at scale. Adding pesticides will further increase the value for money of SiNP-coated cotton seed. A range of NanoSoil Bio products are close to coming to market, with Cong expecting to have scaled up to commercial
production of SiNP by 2026.
Negotiations are underway with CRDC and Cotton Australia to conduct field trials using SiNP-coated cotton seed under varying soil moisture and irrigation regimes. The pasture seed industry is also set to conduct trials to see if the technology can improve the establishment and survival of pasture species in Australian conditions.
Professor Justin Gooding (University of NSW) and Professor Brajesh Singh (Western Sydney University) support Cong in his research and the development of the NanoSoil Bio business.
More information: www.nanosoils.com
Dr Cong Vu, email cong@nanosoils.com