Biology subjects

Darrouzet, E.

Publications and source records attributed to Darrouzet, E..

4 recordsLinked to original sources

bioRxiv2026

Adequate coating and change in morphology increase the performances of silver nanoparticular biocides

Silver has been used as a biocide for centuries, mostly in health-oriented applications. However, as a biocide, silver is toxic not only to its intended targets, mainly bacteria and fungi, but also to all living cells. Because of this toxicity, it is desirable to use forms of silver that maximize the required biocidal activity while minimizing the amount of silver that will be released in the environment at the end of life of the product. Silver nano objects are a good compromise for such requirements. The high surface to volume ratio allows for good reactivity and thus good biocidal activity, while the small amount of silver present in nano objects allows for a limited environmental release at the product end of life. In this work, we tested three types of silver nano objects. The first type, polyvinylpyrrolidone-coated silver nanoparticles (nAg-PVP) were used as a control nanoparticle, as this type of nanoparticle is now widespread. We also manufactured and tested maltodextrin-coated silver nanoparticles (nAg-MD) and micrometric (20 {micro}m in two dimensions and a few nanometers in the third one) silver flakes ({micro}AgSF). For these three silver nano objects, we investigated the biocidal activity by stringent tests using both Staphylococcus aureus and Escherichia coli as target bacteria. In addition, we investigated toxicity on mammalian macrophages or keratinocytes cell lines, as well as on an insect hemocyte cell line. Our results showed that the two innovative silver nano objects (nAg-MD and even more {micro}AgSF), showed both a better bactericidal activity and a lesser toxicity than the reference nAg-PVP nanoparticles. In addition, we also checked that beyond toxicity, the silver nano objects did not induce an inflammatory reaction, making them safer to use.

pharmacology and toxicology↗

bioRxiv2026

Effects of polystyrene and polylactide nanoparticles on macrophages under a repeated exposure mode

Micro and nanoplastics are pollutants which concentration in different biotopes increases continuously over time, which poses the question of their potential effects on health. In animals, these micro and nanoplastics are recognized as particulate materials and thus handled by macrophages, which are therefore a key cell type to study. Most studies have used an experimental scheme in which the cells are exposed to a single dose of plastics, with a readout made immediately after exposure. However, this classical experimental scheme does not take into account the impact of biopersistence, nor the potential cellular adaptation that may take place when cells are exposed repeatedly to a low dose of plastics. We thus used a repeated exposure scheme, in order to better take into account these phenomena. Within this frame, we compared the macrophages responses to a persistent nanoplastic, i.e. polystyrene nanoparticles and to a biodegradable nanoplastic, i.e. polylactide, by a combination of proteomic and targeted experiments. Our results show that under this repeated exposure scheme, the proteome changes were of a lesser (for PS) or similar (for PLA) extent than under the acute exposure mode, indicating cell adaptation. However, PLA particles induced mitochondrial dysfunction and depression of response to bacterial molecules perceived as danger signals, such as lipopolysaccharide. Polystyrene nanoparticles also induced a slight alteration of the immune functions of macrophages. This indicates harmful effects even in the repeated exposure scheme.

pharmacology and toxicology↗

bioRxiv2025

Effects of true to life polyethylene terephthalate and polycaprolactone nanoparticles on macrophages under a repeated exposure mode.

Micro and nanoplastics are pollutants which concentration in different biotopes increases continuously over time, which poses the question of their potential effects on health. In animals, these micro and nanoplastics are recognized as particulate materials and thus handled by macrophages, either directly in the case of lung exposure, or after the particles have crossed the epithelial barriers in case of oral or dermal exposure. It is thus important to study the potential effects of micro and nanoplastics on macrophages. Most studies have used an experimental scheme in which the cells of interest are exposed to a single dose of plastics, and where the readout of the studied parameters is made immediately after exposure. However, this classical experimental scheme does not take into account the impact of biopersistence, nor the potential cellular adaptation that may take place when cells are exposed repeatedly to a low dose of plastics. We thus used a repeated exposure scheme, in order to better take into account these phenomena. Within this frame, we compared the macrophages responses to a persistent nanoplastic, i.e. true-to-life polyethylene terephthalate nanoparticles and to a biodegradable nanoplastic, i.e. polycaprolactone, by a combination of proteomic and targeted experiments. Our results show that under this repeated exposure scheme, the proteome changes were of a lesser extent than under the acute exposure mode, indicating cell adaptation. However, polyethylene terephthalate nanoparticles induced oxidative stress and a pro-inflammatory response, while polycaprolactone nanoparticles induced a depression of macrophages functions, indicating harmful effects even in the repeated exposure scheme.

pharmacology and toxicology↗

bioRxiv2024

Biobased, Biodegradable but not bio-neutral: about the effects of polylactic acid nanoparticles on macrophages

Plastics are persistent pollutants, because of their slow degradation, which suggests that they may lead to cumulative and/or delayed adverse effects due to their progressive accumulation over time. Macroplastics produced by human activity are released in the environment, where they degrade into micro and nanoplastics that are very easily uptaken by a wide variety of organisms, including humans. Microplastics and nanoplastics being particulates, they are handled in the body by specialized cells such as macrophages (or their evolutionary counterparts), where they can elicit a variety of responses. One solution to alleviate the problems due to biopersistence, such as accumulation over life, would be to use biodegradable plastics. One of the emerging biodegradable plastics being polylactide, we decided to test the responses of macrophages to polylactide nanoparticles, using a combination of untargeted proteomics and targeted validation experiments. Proteomics showed important adaptive changes in the proteome in response to exposure to polylactide nanoparticles. These changes affected for example mitochondrial, cytoskeletal and lysosomal proteins, but also proteins implicated in immune functions or redox homeostasis. Validation experiments showed that many of these changes were homeostatic, with no induced oxidative stress and no gross perturbation of the mitochondrial function. However, polylactide particles altered the immune functions such as phagocytosis (-20%) or cytokine production (2-fold increase for TNF production), which may translate into a decreased ability to macrophages to respond to bacterial infections. Furthermore, polylactide particles also induced moderate cross-toxicity with some quinones such as phenanthrene quinone, a combustion by-product that is a suspected carcinogen.

pharmacology and toxicology↗