Glossary of terms



Nanomaterials are officially defined by European Union regulations. Nanomaterials include all materials that have at least one dimension measuring between 1 and 100 nanometres. The nanometric scale of these materials gives them unique physical and chemical properties. Their specific surface area is very large. They have applications in numerous fields, including chemistry, cosmetics, pharmaceuticals, electronics, and aeronautics; nanoparticles belong to the nanomaterial family.

The European Commission defines nanomaterials as:

  • a natural, incidental, or manufactured material ;
  • containing solid particles, in an unbound state or as an aggregate or as an agglomerate;
  • where 50% or more of the particles in the number size distribution meet at least one of the following criteria:
    • (a) for spherical particles: one or more external dimensions is in the size range 1 nm-100 nm;
    • (b) for elongated particles (fibres, tubes, etc.): two external dimensions are less than 1 nm and the other dimension is greater than 100 nm;
    • (c) for particles in the form of plates, sheets, etc.: one external dimension is less than 1 nm and the other dimensions are greater than 100 nm.

The Commission states that any material with a specific-surface-area-to-volume ratio inferior to 6 m2/cm3 should not be considered a nanomaterial.

Nanomaterials are often divided into 2 families: nano-objects and nanostructured materials.

Nanomaterials include nanoparticles (3 dimensions at nanometric scale), nanorods, nanotubes (2 dimensions at nanometric scale — the 3rd may be larger), and nanosheets (sometimes called nanoplates), where only one dimension is at nanometric scale.

Nanostructured materials are materials where the surface is engineered at the nanometric scale (i.e. nanocomposites, solid nanofoams, nanoporous materials and fluid nanodispersions).


Scientists generally use the term ‘nanoparticle’ to mean a particle whose three dimensions measure between 1 and 100 nanometres.


Particles with two dimensions measuring 1 to 100 nanometres are generally referred to as “nanotubes”, “nanorods”, or “nanofibres.” Generally speaking, “nanotube” is used when the object is hollow, and “nanorod” when it is solid. Dimensions can vary depending on the object.


Particles with a single dimension measuring 1 to 100 nanometres are generally referred to as “nanosheets” or “nanoplates.” Dimensions can vary depending on the object.


SPIO, SPION, and USPIO mean the same thing. They stand for “Superparamagnetic Iron Oxide Nanoparticles.” These are iron oxide nanoparticles that have superparamagnetic properties. What this means is that the magnetic properties of these iron oxides only become active when exposed to a magnetic field.


Superparamagnetism is a form of magnetism. It causes metals to exhibit magnetic properties only when exposed to a magnetic field. This only occurs in ferrimagnetic and ferromagnetic materials of nanometric proportions.


This is the name we’ve given our pollution-removing nanoparticles. They feature a unique, exclusive technology that captures metal ions present in polluted wastewater.


Catalysis is a chemical process used to synthesise product (C) from products (A) and (B). Catalysis can either cause or accelerate synthesis. This is achieved using a catalyst (usually a catalytic metal). Heck, Suzuki, and Sonogashira catalytic reactions are the most commonly used forms of catalysis in our field.


Developed using our patented surface engineering technology, our nanocatalysts have a magnetic iron oxide core and are then coated with metals with catalytic properties. Their nanometric proportions mean that they use 100 times fewer critical metals. The superparamagnetic nature of SPIOs means that nanocatalysts can be reclaimed after each reaction and reused up to 10 more times.


The term “agritech” is a combination of the words “agriculture” and “technology.” It refers to all of the technologies used in the agricultural industry. Our relationship to it is that iron oxide nanoparticles can reduce water stress in plants during drought, helping them to better cope with heatwaves and other dry periods.

Precision agriculture

Precision agriculture involves using new technologies, such as nanoparticles, to increase plot yield, optimise work efficiency for farmers, and reduce energy, water, and input use.


Wastewater refers to liquid waste produced by industrial facilities. Generally speaking, wastewater refers to all effluent, surface water, and surface runoff that is discharged through the sewers or drainage systems of population centres.

In solution

When particles or nanoparticles are stored in a liquid, they are said to be “in solution.” This solution may be water or a solvent.


An encapsulated SPIO is a nanoparticle coated with a layer of a particular compound. Nanoparticles are often coated with  silica, which improves their stability  (reduced risk of agglomeration, chemical degradation, or oxidation). This ensures better compatibility with the environment in which they will be used (e.g. improved biocompatibility in medical applications). Coating is sometimes used to functionalise nanoparticles. Additionally, in medicine, encapsulation is useful for controlling the release of drugs into the body.


Measurement of a material’s characteristics. Materials are considered highly characterised when a significant number of their characteristics are known.

Critical metals

Critical metals are elements that are indispensable to modern technology, but for which supplies are limited and susceptible to disruption. Their rarity and specific geographical distribution make them strategic resources. Critical metals include palladium, platinum, rhodium, cobalt, and ruthenium, all of which are needed in a number of industries including the electronics, renewable energies, and advanced technologies sectors. Their rarity makes them very expensive.

Magnetic purification

A process that employs a magnetic system to purify wastewater. SON harnesses the superparamagnetic properties of its nanoscavengers and nanocatalysts to retrieve them from the environments in which they are found.


Ferrite nanoparticles are Fe2MO₄ nanoparticles that we extract an iron atom from to replace it with another metal (manganese, cobalt, zinc, etc.). What makes them unique is that their superparamagnetic properties are even better than those of conventional nanoparticles, making them even more effective.


Macrophages are cells that are part of the human body’s innate immune system. They are vital to our immune defences and destroy bacteria and viruses. Macrophages protect our bodies from all kinds of pathogens and foreign substances. Researchers employing nanoparticles in drug treatments try to lure away macrophages so that therapeutic nanoparticles can be allowed to enter the body.


The term “theranostics” refers to a technique that combines two concepts: “therapy” and “diagnosis.” It therefore refers to both the diagnosis and treatment of a disease. For instance, during projects in partnership with the CGFL in Dijon (Centre Régional De Lutte Contre Le Cancer Georges-François Leclerc – Georges-François Leclerc Regional Cancer Centre), SON devised a technique capable of detecting glioblastomas (brain cancer), locating them, and finally eliminating them, all without damaging the healthy tissue surrounding the tumour.


Chelator molecules are used to capture foreign substances in a given medium. Here at SON, we use DTPA (diethylenetriaminepentaacetic acid) as a chelator to purify wastewater by capturing metal ions.

Surface plasmon resonance

Surface plasmon resonance (SPR) is a phenomenon that occurs at the nanometric scale when light excites the surface of a conductive material, like gold, that has a thin dielectric coating. When light hits this surface, it creates oscillations in the free electrons on the surface of the material, which are known as surface plasmons. This interaction between the light and the electrons produces a distinctive optical signature known as surface plasmon resonance.

The thing that makes SPR so interesting is that it is very sensitive to changes on a material’s surface. For example, if molecules bind to the metal-coated surface, this quantifiably alters the optical properties of the SPR. This means that SPR can be used to both detect and analyse extremely low concentrations of molecules like proteins or antibodies. This makes the technique invaluable in biology and medicine. Thanks to Surface-Enhanced Raman Spectroscopy (SERS), we’ll soon be able to make early diagnosis of a number of diseases, such as cancer and neurodegenerative diseases.

Lateral flow

Lateral flow is a screening method, also known as immunochromatography. It can be applied in self-tests (COVID-19, pregnancy tests, flu tests, etc.) and has the advantage of being quick and easy to use. These tests use gold nanoparticles.

Magnetic separation

In nanomedicine, the magnetic separation of cells allows different types of biological materials, such as cell types, intracellular organelles, proteins, or nucleic acids, to be selected or eliminated. Once selected, it’s then possible, for example, to analyse them for diagnostic purposes.


Substances are said to be miscible when they fully mix together to form a homogeneous mixture.


Molecules are said to be hydrophobic when they are immiscible in water. Instead, such hydrophobic molecules have an affinity for nonpolar solvents.

Drug vectorisation

This process is used in nanomedicine. It involves delivering drugs directly to diseased cells to prevent healthy cells from being affected by the drug. Our nanoparticles can be used as vectors to effectively deliver molecules to the human body. Their size means they can penetrate certain immune defences and remain undetected by macrophages, which then allow them access to the body.


Biomanufacturing is the production of biological substances, such as proteins, enzymes, drugs, or biofuels, using microorganisms, plant or animal cells, or synthetic biological systems.

There are high expectations for this fairly recent technique. It may prove to be more environmentally friendly than existing technologies, as it generates less waste requiring subsequent processing.


Biocompatibility refers to a material’s ability to interact with a biological system without causing adverse reactions. This implies a lack of toxicity, irritation, or adverse immune reactions on contact with living tissue.

Functionalised nanoparticles

Nanoparticles are functionalised when atoms or molecules are grafted onto their surface.

Magnetic hyperthermia

Magnetic hyperthermia is a treatment technique that uses magnetic nanoparticles to generate heat when exposed to a magnetic field. This heat can be used against cancerous tumours, destroying cancer cells without damaging surrounding healthy tissue. This is a promising approach that is currently undergoing development. It provides targeted, non-invasive treatment.

MRI (Magnetic Resonance Imaging)

MRI (Magnetic Resonance Imaging) is a medical imaging technique that uses magnetic fields to produce detailed images of the body’s internal tissues. Exposing the body to a powerful magnetic field causes protons in tissues to realign, thus making them detectable by the machine. This produces cross-sectional or three-dimensional images. MRI is widely used to diagnose and monitor brain injuries, heart disease, and tumours.


Monodisperse nanoparticles are uniformly sized nanoparticles that are neither agglomerated nor aggregated and are minimally dispersed within the production batch. The use of highly characterised and perfectly reproducible nanoparticles is crucial to ensuring experiment reproducibility.