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New “Safer-by-Design” biocides based on silver nanoparticles

Researchers at the CEA-Irig have developed a new concept in nanomaterials involving an assembly of silver nanoparticles linked by a bio-inspired molecule.

Published on 10 September 2020

Silver nanoparticles (AgNP) are biocides used to destroy viruses and bacteria in consumer products and medical devices. They release bio-available Ag(I) ions, making them long-acting biocides. Nevertheless, AgNPs are typically released quickly from the product, which limits their action over time. In addition, AgNPs are very sensitive to various chemical environments that can lead to their transformation, thus decreasing their activity. Overall, although useful, the widespread use of AgNPs leads to bacterial resistance and health safety problems, requiring innovation in products that are safer for humans and the environment.

CEA-Irig researchers have now developed a new Safer-by-Design concept for nanomaterials. This consists of an assembly of silver nanoparticles linked together by a bio-inspired molecule that binds covalently to the surface of the nanoparticles through its three thiol functions. The result is a nanomaterial that can release Ag(I) ions in a slow and controlled manner, in contrast to the AgNPs currently used as biocides, which undergo uncontrolled processes of transformation and product release. The AgNP assemblies that have been developed allow the establishment of a scaffolding that protects the nanoparticles from massive transformations induced by various environmental conditions. Furthermore, these architectures do not prevent the release of Ag(I) but only slow it down, providing a nanomaterial that can be considered as a promising new safer biocide.

All of the assemblies have anti-bacterial activity against gram-negative, as well as gram-positive bacteria. The latter is particularly interesting since AgNPs are generally not active against this type of bacteria, in particular due to their ability to modify the surface of nanoparticles. Moreover, no toxicity from AgNP assemblies was observed when a human hepatocarcinoma cell line was exposed to them. AgNP assemblies therefore possess broad-spectrum biocidal activity, and their cytotoxicity for eukaryotic cells is significantly lower than that of AgNP alone. The release of Ag(I) ions from these assemblies can be adjusted, and their low sensitivity to the surrounding environment makes them a long-lasting biocide whose risks to humans and the environment are considerably reduced compared to the technologies currently in use.

This work is supported by the LabEx SERENADE (Laboratory of Excellence for Safe(r) Ecodesign Research and Education applied to NAnomaterial DEvelopment).


Interdisciplinary Research Institute of Grenoble (IRIG - CEA/CNRS/Université Grenoble Alpes)

​Pasteur Institut
Collège de France

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