Content: Nanoparticles showed a huge potential for new properties development in many economic sectors like electronics, medicine, textile, waste water treatment etc. The modification of surface functionality by using low concentrations of nanomaterials opens the possibility of lowering the ecological impact of chemical materials based on volatile organic compounds. The objectives of our research were related to the use of commercial nanoparticles based on Ag and TiO2 with average particle size of 8 nm for leather surface functionalization and the investigation of the cytotoxicological impact of nanoparticle concentrations on human skin cells. The practical implications of the approach consist of multifunctional leather surface development, leather durability and comfort increase by generating antimicrobial and self-cleaning properties. The relation between leather functionality and the cytotoxicity concentration limit of nanomaterials was the hypothesis of our research. The main procedures for leather surface covering followed the classical recipes based on surface spraying with film forming composites with nanoparticle content. The optimized technology was evaluated by leather surface analyses regarding the antimicrobial (SR EN ISO 20645) and self-cleaning properties under UV and visible light exposure as compared to leather surface covered without nanoparticles. The cytotoxicity tests were performed by incubation of keratinocytes (Human immortalized keratinocytes-HaCaT) with different concentrations of nanoparticles for 48 hours and measurement of cell viability by MTT (3-[4,5-dimethylthiazol- 2-yl]-2,5-diphenyltetrazolium bromide) assay protocol. Other tests were devoted to leather wearing simulation in order to estimate the potential transfer of nanoparticles on human skin and the health and safety impact. These simulations were based on rubbing test (SR EN ISO 11640) followed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) analyses and by leachability tests (SR EN ISO 4098) performed in artificial perspiration solution followed by inductively coupled plasma -mass spectrometry (ICP-MS) analyses, according to SR EN ISO 17294-2 and SR EN ISO 16171. The main conclusions of our research showed that it is possible to add multifunctional value to leather surface by using Ag and TiO2 nanoparticles with low impact on safety and health. Acknowledgements: The works were funded by UEFISCDI and MCI, project number PNIII_15/2015-2018 under the frame of SIINN, the ERA-NET for a Safe Implementation of Innovative Nanoscience and Nanotechnology program and respectively, PN 19 XX 05 01 project/2019 under Nucleus program TEX-PELVISION 2022 Take-Away: - antimicrobial and self-cleanning nanoparticles for leather surface finishing - Ag and TiO2 nanoparticle cytotoxicity tests for human skin cells - multifunctional surface properties with low cytotoxicological impact

yes / Ibuprofen (IBF) is an outstanding non-steroidal drug for analgesic and anti-inflammatory therapies but it exhibits poor solubility in water [1, 2]. Increased dosage administration has been linked to gastrointestinal and cardiovascular complications [3]. Many techniques have been employed to improve the solubility of NSAIDs [4]. In this study, the anti-solvent precipitation method was used to make Ibuprofen nanoparticles (IBF NPs). Optimised preparation parameters such as solvent (ethanol), raw drug concentration (400 mg), solvent/anti-solvent ratio (1:50) and surfactant concentration (0.25 mg/ml) have been studied to yield nanoparticles with a mean size of 58.8 nm, which is confirmed by dynamic light scattering and transmission electron microscopy. These IBF NPs posess increased aqueous solubility compared to the micro counterpart and maintain with chemical integrity indicated by high performance liquid chromatography and Fourier transform infrared spectroscopy. In addition, in vitro cytotoxicity of IBF NPs has been studied on A549 and HaCat cell lines using MTT and LDH assays. Both cells were obtained from ATCC. The A549 cells were grown in a modification of Ham’s F-12, containing L-glutamine, called F-12K. The HaCaT cells were grown in DMEM containing sodium pyruvate (110 mg/l). Normal cell culture and sub-culture were applied and the cells were used after around 45 passages [5]. The cell culture media containing 105cells/ml were placed in a 96-well plate with addition of IBF NPs and Micro form at concentrations in the range of between 6 and 500 ug/ml by diluting them with DMEM and F-12K for use with the HaCaT and A549 cells respectively. After 24, 48 and 72h exposure, the MTT and LDH cytotoxicity assay were performed in triplicates and on three separate experiment cultures and the absorbance was recorded at 570 nm and 492nm respectively with Elisa micro plate reader. The cell viability (%) related to control (cells in culture medium without NPs) was calculated. A very good cytotoxicity profile was observed, indicating an in vitro cytocompatibility of the IBF NPs in these cell culture systems and no significant changes in cytotoxicity compared with Micro IBF. We conclude that our IBF NPs have increased solubility, same chemical integrity and unchanged cytotoxicity compared to IBF Micro drug. Further work will concentrate on optimising more rigorous parameter to produce excellent quality NPs. More detailed characterisation of IBF NPs is to be tested, such as using PXRD and SEM to further corroborate particle shape and size. The range of no toxic in vitro concentrations is also to be further confirmed. Eventually scaled up preparation of IBF NPs will be developed without relinquishing NPs quality. This would improve the potential for in vitro/ in vivo applications and clinical use of IBF NPs and NSAIDs in general.

yes / Nanoparticles are increasingly used in industry and medicine due to their unique physiochemical properties such as their small size, charge, shape, chemical architecture, large surface area, surface reactivity and media interactions, etc [1-5]. However, very little is still known on the interactions between nanoparticles and the biological system. This study aims to evaluate the cytotoxicity of polystyrene latex bead nanoparticles on HaCat and HeLa cell lines. Carboxyl-modified 20 nm polystyrene NPs core labelled with fluorophore were from Invitogen. We chose to use polystyrene NPs because this specific type of NP is being increasingly characterized for use in nanosensors and drug nanocarrier investigations. 1x 104 cells/100 μl of cell culture medium were plated into 96-well plates in triplicate, measuring activity post 24 hours at concentrations of 10, 50, 100 μg/ml of polystyrene NPs exposure. The extracellular lactate dehydrogenase release was measured by using a colorimetric CytoTox 96 nonradioactive assay kit from Promega and the absorbance were recorded at 450nm (FLUO-star) with Elisa micro plate reader. The MTT assay was used to evaluate mitochondrial activity. This was performed by inserting a premixed optimized dye solution in the culture wells. The Absorbance was recorded at 570 nm, from the recorded absorbance is directly proportional to the number of live cells. The cell lines were kept in a plastic T-75cm2 tissue culture flasks grown in DMEM. We found that cytotoxicity of polystyrene NPs on both cells was concentration dependent. For Hela cells, with exporesure of polystyrene NPs at concentrations of 10, 50, 100 μg/ml for 24 hrs, the percentage cytotoxicity of positive control for LDH assay was 35.9%, 49.5% and 73.4% respectively. With the MTT cell viability assay the percentage MTT reduction of negative control was 88.9%, 42.9% and 26.4% respectively. Cell toxicity increased with increasing polystyrene NPs concentration. For HaCaT cells, the cytotoxic effect is less significant than those on Hela cells. With MTT assay, when compared to HaCaT cells exposed to a negative control containing only PBS, the cell viability decreased as the concentrations of NPs increased. Cells exposed to 100μg/ml of polystyrene NPs for a period of 24 hours compared to those exposed to a positive control (100% cell viability) had an average cell viability of 49%, with those numbers decreasing from 59% for cells exposed to 10μg/ml of polystyrene NPs to 57% for cells exposed to 50μg/ml of polystyrene NPs. Our results indicated that polystyrene NPs acted differently in two different cell types and that cautions should be taken about its cytotoxicity. Further understanding of the mechanism involving the ROS generation could provide more information on how polystyrene NPs increase cytotoxicity.

Microbial resistance to the current available antibiotics is considered a global health problem, especially for the Multi-Drug Resistant pathogens (MDR) including methicillin resistant Staphylococcus aureus. Recently nanoparticles (NPs) have been involved in variety of antimicrobial applications due to their unique properties of antibacterial effects. However, the molecular mechanisms behind their antibacterial activity are still not fully understood. In this study, we produced silver Ag NPs (average size 27 nm) and silver-Titanium Ag-TiO2 NPs (average size 47 nm) using picosecond laser ablation. Our results showed that both laser NPs had obvious size-dependent antibacterial activity. The laser Ag NPs with a size of 19 nm and Ag-TiO2 NPs with a size 20 nm presented the highest bactericidal effect. The laser generated Ag and Ag-TiO2 NPs with concentrations 20, 30, 40, and 50 Î1⁄4g/ml showed strong antibacterial effect against three bacterial strains: E. coli, P. aeruginosa, and S. aureus, and induced the generation of reactive oxygen species (ROS), lead to cell membrane interruption, lipid peroxidation, DNA damages, glutathione depletion and the eventual cell death. Both types of laser NPs at two concentrations (2.5 and 20 Î1⁄4g/ml) showed low cytotoxicity to the in vitro cultured five types of human cells originated from the lung (A549), kidney (HEK293), Liver (HepG2), skin (HDFc) and blood vessel cells (hCAECs). The antibacterial activity of the laser generated Ag and Ag-TiO2 NPs had lasted for over one year depending on the degree of air exposure and storage conditions. Frequent air exposure increased particle oxidation and reduced the antibacterial durability of the laser generated Ag NPs. The laser generated Ag NPs had lower antibacterial activity when stored in cold compared to that stored at room temperature. The antibacterial activity of laser generated Ag and Ag-TiO2 NPs were also compared with four types of commercial based-silver wound dressings (Acticoat TM, Aquacel® Ag, Contreet ®Foam, and Urgotul® SSD) against E. coli to inform future application in this area. In conclusion, laser generated Ag and Ag-TiO2 NPs have strong bactericidal effect and low toxicity to human cells which could be a type of promising antibacterial agents for future hygiene and medical applications.

Les nanoparticules d’oxyde de fer de structure spinelle ouvrent de nombreuses voies dans le domaine biomédical. Parmi les applications possibles, les propriétés superparamagnétiques des cristallites d'une dizaine de nanomètres permettent de les utiliser pour le diagnostic médical, notamment en Imagerie par Résonance Magnétique (IRM).Ce travail a consisté à élaborer des suspensions colloïdales de nanoparticules de magnétite ou de maghémite (nommées USPIO pour Ultrasmall SuperParamagnetic Iron Oxide) compatibles avec les conditions physiologiques (pH = 7,4 et [NaCl] = 0,15 M).Par co-précipitation classique, des USPIO, de taille de cristallites de 8 nm, de surface spécifique de 110 m².g-1 et agrégés en assemblages d’environ 20 nm ont été obtenus. Pour stabiliser ces nano-objets, deux voies ont été explorées. Des agents électrostatiques (acide citrique et DMSA) ont modifié la charge nette de surface des oxydes de fer. La stabilisation stérique a également été explorée par greffage de méthoxy-PEG couplés à des fonctions silanes (mPEG-Si). Par combinaison de mPEG2000-Si et de DMSA, des suspensions stables ont également été obtenues. De plus, les fonctions thiols apportées par le DMSA et présentes à la surface des agrégats se trouvent protégées de leur oxydation naturelle par l'encombrement stérique des chaînes de polymère (la formation de ponts disulfures est évitée). La post-fonctionnalisation de ces nanoparticules via ces fonctions thiols est alors possible plusieurs semaines après leur synthèse. Ce concept a été validé par post-greffage d’un fluorophore (0,48 RITC/nm²) pour la détection in vitro en microscopie à fluorescence.En parallèle de cette étude en « batch », des nanoparticules d’oxyde de fer ont été synthétisées en continu à l’aide d’un procédé hydrothermal pouvant s’étendre au domaine eau supercritique. En voie hydrothermale classique, des USPIO stabilisés par des ions citrates ont été obtenus en continu. Grâce aux propriétés physicochimiques de l’eau supercritique, la co-précipitation de magnétite a été possible sans l’utilisation de base.La cytotoxicité et l’internalisation cellulaire de ces USPIO ont été évaluées sur trois modèles cellulaires (macrophages RAW, hépatocytes HepG2 et cardiomyocytes) et les efficacités comme agents de contraste en IRM de ces nanoparticles ont été mesurées sur gel et sur modèle murin et comparées à un agent de contraste commercial à base d’oxyde de fer. Les nanohybrides étudiés n’ont pas présenté de cytotoxicité et ont développé des pouvoirs contrastants comparables à l’agent commercial. La biodistribution hépatique des nanoparticules couplées au mPEG-Si a été retardée de plus de 3 heures ouvrant la voie à des détections spécifiques. / Spinel structured iron oxide nanoparticles open the way of biomedical applications of nanomaterials.Superparamagnetic properties of ten nanometer size crystallites permit to use them in diagnosis such as Magnetic Resonance Imaging (MRI).The aim of this work was to synthesize colloidal suspension of magnetite or maghemite (called USPIO for Ultrasmall SuperParamagnetic Iron Oxide) stable in physiological conditions (pH = 7.4 and [NaCl] = 0.15M).By classical co-precipitation method, UPSIO were synthesized with a mean crystallite size of 8 nm, with a specific surface area of 110 m².g-1 and an aggregate size of 20 nm. To stabilize these nano-objects, two ways were investigated. Electrostatic agents (like citric acid and DMSA) modified iron oxide surface charge. Steric stabilization was also studied by grafting methoxy-PEG coupled with a silane function (mPEG-Si).and the combination mPEG - DMSA also resulted in stable suspensions. Moreover thiols functions coming from DMSA and present on the surface of the nanoparticles were prevented from oxidation thanks to steric protection of polymer chains. Thanks to this method post-functionalization of USPIO was possible several weeks after synthesis. This concept was validated with the post-grafting of a dye (0.48 RITC per nm²) used for in vitro detection in fluorescent microscopy.Nanoparticles were also synthesized in a continuous way with a hydrothermal process which could work from soft chemistry to supercritical water. In classical hydrothermal conditions, USPIO stabilized with citrates were obtained in a continuous way. Thanks to the physico-chemical properties of supercritical water, co-precipitation of magnetite without base adding was possible.Cytotoxicity and cellular internalization assays were done with our USPIO in three cellular models (macrophages RAW, hepatocytes HePG2 and cardiomyocytes). Moreover the efficiency as MRI contrast agents were measured in gels tubes and on mice models and compared to an iron oxide commercial product. Late hepatic biodistribution (more than three hours) was proven with pegylated nanoparticles, which opens the way of specific detections.