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In the last century, industrial activities increased and caused multiple health problems for humans and animals. At this moment, heavy metals are considered the most harmful substances for their effects on organisms and humans. The impact of these toxic metals, which have no biological role, poses a considerable threat and is associated with several health problems. Heavy metals can interfere with metabolic processes and can sometimes act as pseudo-elements. The zebrafish is an animal model progressively used to expose the toxic effects of diverse compounds and to find treatments for different devastating diseases that human beings are currently facing. This review aims to analyse and discuss the value of zebrafish as animal models used in neurological conditions, such as Alzheimer’s disease (AD), and Parkinson’s disease (PD), particularly in terms of the benefits of animal models and the limitations that exist.

Environmental contamination from toxic metals and pesticides is an issue of great concern due to their harmful effects to human health and the ecosystems. In this framework, we assessed the adverse effects when aquatic organisms are exposed to toxicants such as deltamethrin (DM) and lead (Pb), alone or in combination, using zebrafish as a model. Moreover, we likewise evaluated the possible protective effect of vitamin C (VC) supplementation against the combined acute toxic effects of the two toxicants. Juvenile zebrafish were exposed to DM (2 μg L−1) and Pb (60 μg L−1) alone and in combination with VC (100 μg L−1) and responses were assessed by quantifying acetylcholinesterase (AChE) activity, lipid peroxidation (MDA), some antioxidant enzyme activities (SOD and GPx), three-dimension locomotion responses and changes of elements concentrations in the zebrafish body. Our results show that VC has mitigative effects against behavioral and biochemical alterations induced by a mixture of contaminants, demonstrating that it can be used as an effective antioxidant. Moreover, the observations in the study demonstrate zebrafish as a promising in vivo model for assessing the neuroprotective actions of bioactive compounds.

Heavy metal pollution is still present in the Danube River basin, due to intensive naval and agricultural activities conducted in the area. Therefore, continuous monitoring of this pivotal aquatic macro-system is necessary, through the development and optimization of monitoring methodologies. The main objective of the present study was to develop a prediction model for heavy metals accumulation in biological tissues, based on field gathered data which uses bioindicators (fish) and oxidative stress (OS) biomarkers. Samples of water and fish were collected from the lower sector of Danube River (DR), Danube Delta (DD) and Black Sea (BS). The following indicators were analyzed in samples: cadmium (Cd), lead (Pb), iron (Fe), zinc (Zn), copper (Cu) (in water and fish tissues), respectively, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA) (in fish tissues). The pollution index (PI) was calculated to identify the most polluted studied ecosystem, which revealed that Danube River is seriously affected by the presence of Fe (IP = 4887) and strongly affected by the presence of Zn (IP = 4.49). The concentration of Cd in fish muscle tissue was above the maximum permitted level (0.05 µg/g) by the EU regulation. From all analyzed OS biomarkers, MDA registered the highest median values in fish muscle (145.7 nmol/mg protein in DR, 201.03 nmol/mg protein in DD, 148.58 nmol/mg protein in BS) and fish liver (200.28 nmol/mg protein in DR, 163.67 nmol/mg protein, 158.51 nmol/mg protein), compared to CAT, SOD and GPx. The prediction of Cd, Pb, Zn, Fe and Cu in fish hepatic and muscle tissue was determined based on CAT, SOD, GPx and MDA, by using non-linear tree-based RF prediction models. The analysis emphasizes that MDA in hepatic tissue is the most important independent variable for predicting heavy metals in fish muscle and tissues at BS coast, followed by GPx in both hepatic and muscle tissues. The RF analytical framework revealed that CAT in muscle tissue, respectively, MDA and GPx in hepatic tissues are most common predictors for determining the heavy metals concentration in both muscle and hepatic tissues in DD area. For DR, the MDA in muscle, followed by MDA in hepatic tissue are the main predictors in RF analysis.

The overuse of antibiotics combined with the limitation of wastewater facilities has resulted in drug residue accumulation in the natural environment. Thus, in recent years, the presence of antibiotic residues in the environment has raised concerns over the potential harmful effects on ecosystems and human health. The in vivo studies represent an essential step to study the potential impact induced by pharmaceutical exposure. Due to the limitations of traditional vertebrate model systems, zebrafish (Danio rerio) has recently emerged as a promising animal model to study the toxic effects of drugs and their therapeutic efficacy. The present review summarizes the recent advances made on the toxicity of seven representative classes of antibiotics, namely aminoglycosides, β-lactams, macrolides, quinolones, sulfonamides, tetracyclines and polyether antibiotics, in zebrafish, as well as the combined effects of antibiotic mixtures, to date. Despite a significant amount of the literature describing the impact of single antibiotic exposure, little information exists on the effects of antibiotic mixtures using zebrafish as an animal model. Most of the research papers on this topic have focused on antibiotic toxicity in zebrafish across different developmental stages rather than on their efficacy assessment.

Plastics entering the environment will persist and continue to degrade and fragment to smaller particles under the action of various environmental factors. These microplastics (MP) and nanoplastics (NP) are likely to pose a higher environmental impact, as well as they are more prone to adsorb organic contaminants and pathogens from the surrounding media, due to their higher surface area to volume ratio. Little known on their characteristics, fragmentation, distribution and impact on freshwater ecosystems. In order to respond to these open questions concerning the plastic particles dynamics and their environmental effects, detailed sampling strategies as well as an automated, rapid, cheap and reliable analytical technique suitable for routine analysis need to be developed. The review outlines the recent advances made on examination of the potential toxicological effects of MP and NP on freshwater biota, as well as the available analytical methods employed to identify and quantify them in environmental samples.

In the current study the response of aquatic macroinvertebrate communities to multiple anthropogenic stressors in a typical lowland river that crosses pristine sectors situated toward headwaters, as well as densely populated urban areas was assessed. We wished to develop an effective bioassay procedure for assessing water and sediment quality in lotic ecosystems from Romania with the aid of macroinvertebrate organisms correlated with physico-chemical parameters and pollutants in both dissolved fractions and material bonded to sediment. A fast scanning approach of the river, from springs to the mouth, was employed. We found significant changes in physico-chemical parameters along a longitudinal gradient, the highest values being registered within the urban area and heavily agriculturally developed areas. The macroinvertebrates showed affinities for certain abiotic factors, emphasising their potential use for future studies as reliable ecological indicators, shaped by a synergic combination of urban effects and magnitude of type of land use.

Background. As every organ within the body, the brain is also extremely susceptible to a plethora of noxious agents that change its chemistry. One component frequently found in current products against harmful species to crops is rotenone whose effect under prolonged exposure has been demonstrated to cause neurodegenerative disorders such as Parkinson’s disease. The latest reports have indeed revealed that rotenone promotes Parkinson’s in humans, but studies aiming to show congruent effects in zebrafish (Danio rerio) are lacking. Material and Methods. In this context, the aim of the present study was to demonstrate how chronic administration of rotenone for 3 weeks impairs the locomotor activity and sociability and induces oxidative stress in zebrafish. Results. There were no statistically significant differences following the analysis of their social interaction and locomotor tests ( p > 0.05 ). However, several exceptions have been noted in the control, rotenone, and probiotics groups when we compared their locomotor activity during the pretreatment and treatment interval ( p < 0.05 ). We further assessed the role of rotenone in disturbing the detoxifying system as represented by three enzymes known as superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA). Despite the fact that there were no statistically significant changes within SOD and GPx levels between the control group and rotenone, probiotics, and rotenone + probiotics ( p > 0.05 ), relevant changes have been observed between the analyzed groups ( p < 0.05 and p < 0.005 , respectively). On the other hand, significant differences ( p < 0.05 ) have been observed for MDA when we analyzed the data between the control group and the other three groups. Conclusions. Our results suggest that rotenone can be successfully used to trigger Parkinson’s disease-related symptomatology in zebrafish.

In this study, graphene oxide (GO), polyethyleneimine (PEI) and potassium hydroxide (KOH) were used to synthesize reduced graphene oxide (rGO/PEI-KOH) nanocomposite. The presence and grafting of PEI molecules on the reduced GO surface were assessed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) analyses. The rGO/PEI-KOH nanocomposite was successfully applied for hexavalent chromium, Cr(VI), wastewater elimination. The resulting rGO/PEI-KOH adsorbent was found to be highly effective for Cr(VI) removal at low pH values and achieved a maximum capacity of experimental adsorption of 398.9 mg/g, which is one of the highest sorption capacity of most GO- and PEI-based adsorbents reported in the literature up to date. Studying the adsorption mechanism, the sorption isotherm revealed that the modified-Langmuir model was the best fit and Cr(VI) removal follows a pseudo-second-order kinetics, with the predominance of intraparticle diffusion during the first step of adsorption. XPS analysis indicated the presence of appreciable amount of Cr(III) on the adsorbent surface, which suggests that the adsorbed Cr(VI) ions were effectively reduced to Cr(III) on the rGO/PEI-KOH adsorbent surface (∼70% of the total adsorbed Cr). Cr(VI) adsorption and subsequent reduction to Cr(III) both contributed to the Cr(VI) removal. The results of the present study highlight the benefits of rGO/PEI-KOH like low cost, environmentally friendly, large toxic Cr(VI) ions adsorption capacity and its effective reduction to less-toxic Cr(III).

Chronic exposure to synthetic insecticides in the early life of a child can lead to a series of disorders. Several causes as parental age, maternal smoking, birth complications, and exposure to toxins such as insecticides on childhood can lead to Autism spectrum disorder (ASD) occurrence. The aim of this study was to evaluate the potential protective role of vitamin C (Vit. C) from children&rsquo, s supplements after 14 days chronic exposure to insecticide mixture fipronil (Fip) + pyriproxyfen (Pyr) on juvenile zebrafish for swimming performances, social behavior and oxidative stress associated with ASD model. Juvenile (14&ndash, 17 mm) wild-type AB zebrafish (Danio rerio) (45 days) were exposed to relevant concentrations: vit. C (25 &micro, g L&minus, 1), Fip (600 &micro, 1/1.372 &mu, M) + Pyr (600 &micro, 1/1.89 &mu, M), and [Fip (600 &micro, 1 /1.89 &mu, M)] + vit. C (25 &micro, 1). Our results showed that insecticides can disturb the social behavior of zebrafish during 14 days of the administration, decreased the swimming performances, and elevated the oxidative stress biomarkers of SOD (superoxide dismutase), GPx (glutathione peroxidase), and MDA (malondialdehyde). The vitamin C supplement significantly attenuated the neurotoxicity of insecticide mixture and oxidative stress. This study provides possible in vivo evidence to show that vitamin C supplements could attenuate oxidative stress and brain damage of fipronil and pyriproxyfen insecticide chronic exposure on zebrafish juvenile.

The current study aims to assess the pollution status of the European river-sea system lower Danube River-Danube Delta-North West Black Sea, through an integrated analysis of metal concentrations in water, sediments and fish community. The Danube flows through numerous industrial cities and receives a significant amount of pollutants due to the reception of urban and industrial emissaries, as well as agricultural land runoff. Samples of water, sediments and fish (10 species) were collected from 7 representative sites along Danube River, Danube Delta and Black Sea shore. For the analysed fish species, potentially toxic and essential elements (Pb, Cd, As, Cu, Fe, Zn, Mg, Ca, Na, K) from muscle and liver samples were measured and discussed. Measurement of elements and other environmental quality parameters were determined for water and sediments. The Black Sea area, represented by S6 and S7, received sediments from Danube with the lowest concentrations of Cd (0.05 ± 0.01 μg g−1, respectively 0.01 ± 0.001 μg g−1), Pb (3 ± 0.03 μg g−1, respectively 2 ± 0.03 μg g−1), As (2 ± 0.02 μg g−1, respectively 1.4 ± 0.3 μg g−1), Ni (8.9 ± 0.1 μg g−1, respectively 5.2 ± 0.2 μg g−1), Cr (8 ± 0.7 μg g−1, respectively 5 ± 0.2 μg g−1), Cu (3 ± 0.1 μg g−1, respectively 2 ± 0.04 μg g−1), Fe(6 ± 0.3 μg g−1, respectively 3 ± 0.1 μg g−1) and Zn (0.03 ± 0.003 μg g−1, respectively 0.017 ± 0.001 μg g−1). These results suggest that the Danube Delta system plays an important role in filtering the pollutants. Based on the biota and water analysis, there was no correlation observed between Cd, respectively Pb concentration in the environment and fish body (Person Coef. = −0.02 in muscle tissue and −0.01 in liver tissue, respectively Pearson Coeff. = −0.06 in muscle tissue and 0.1 in liver tissue). Cadmium remained an active element in the pollution of the Danube area (S1 and S2), with high concentration in the water matrix (0.14 ± 0.02 μg L−1, respectively 0.05 ± 0.01 μg L−1) and fish muscle (0.15 ± 0.03 μg g−1f.w. in C. carpio – S2). This fact was confirmed by several other studies.

Particle-based photodynamic therapy (PPDT) holds great promise in theranostic applications. Herein, we demonstrate that PPDT based on gold nanorods coated with an indocyanine green (ICG)-loaded silica shell allows for the inactivation of the Crohn's disease-associated adherent-invasive Escherichia coli strain LF82 (E. coli LF82) under pulsed laser light irradiation at 810 nm. Fine-tuning of the plasmonic structures together with maximizing the photosensitizer loading onto the nanostructures allowed optimizing the singlet oxygen generation capability and the PPDT efficiency. Using a nanoparticle concentration low enough to suppress photothermal heating effects, 6 log10 reduction in E. coli LF82 viability could be achieved using gold nanostructures displaying a plasmonic band at 900 nm. An additional modality of nanoparticle-based photoinactivation of E. coli is partly observed, with 3 log10 reduction of bacterial viability using Au NRs@SiO2 without ICG, due to the two-photon induced formation of reactive oxygen species. Interaction of the particles with the bacterial surface, responsible for the disruption of the bacterial integrity, together with the generation of moderate quantities of singlet oxygen could account for this behavior.

International audience; In the last years, carbon-based nanomaterials have attracted considerable attention in a wide range of fields, particularly in biomedicine, owing to their remarkable photo-physical and chemical properties. In this study, we demonstrate that amine-terminated carbon dots (CDs-NH2) functionalized with ampicillin (AMP) offer a new perspective for antibacterial treatment. The amine-functionalized carbon dots were used as a carrier for immobilization and delivery of ampicillin (CDs-AMP) and as a visible light-triggered antibacterial material. Additionally, AMP immobilization on the CDs-NH2 surface improves its stability in solution as compared to free AMP. The AMP conjugated CDs platform combines the antibacterial function of AMP and conserves the intrinsic theranostic properties of CDs-NH2. Therefore, the AMP immobilized onto CDs-NH2 surface together with the generation of moderate quantities of reactive oxygen species under visible light illumination is very effective to inactivate the growth of Escherichia coli.

In part 1 (A. Vasilescu et al., Porous reduced graphene oxide modified electrodes for the analysis of protein aggregation. Part 1: Lysozyme aggregation at pH 2 and 7.4 Electrochem. Acta, 254 (2017) 375–383) we proposed porous reduced graphene oxide coated glassy carbon electrode (GC/prGO) in combination with differential pulse voltammetry as a new analytical tool for aggregation studies of proteins. Lysozyme was used as a model to follow its aggregation by electrochemical means at pH 2 and pH 7.4, leading to the formation of amyloid and amorphous aggregates, respectively. Part 2 of this work widens the scope of this approach by investigating a biopharmaceutical product, as the aggregation of peptide based drugs affects their therapeutic activity and can induce allergic reactions in patients. The salmon polypeptide calcitonin (sCT) was chosen as an example of a bioactive peptide with limited pharmaceutical potential due to a tendency to form cytotoxic aggregates and amyloid fibrils. For practical applications, screen printed electrodes (SPE) and flexible electrodes (FE) modified with polydiallyldimethylammonium (PDDA) and prGO by using the layer-by-layer deposition technique have been developed for the detection of sCT. The results indicate that these electrodes can differentiate between formation of amyloid aggregates of calcitonin (2 mg mL−1) in citrate buffer to no aggregation in acetate buffer. It was further demonstrated that these electrodes are able to analyze a pharmaceutical drug product of low potency, Miacalcic (8.3 μg mL−1), where no aggregation was observed.

International audience; Numerous antimicrobial drugs have been developed and commercialized to kill and inhibit the growth of pathogenic microbes. The therapeutic efficiency of these drugs has however become often inadequate for the treatment of microbial infections, the reasons being multiple. Oral administration results often in only partial absorption and up to 50% of the active compound can be excreted in the urine. Furthermore, antibiotic therapy is also frequently accompanied by gastrointestinal complications, including vomiting, nausea and diarrhea. From a therapeutic point of view, the low solubility of antibiotics in lipid membranes presents a limitation for rapid and efficient treatment of infections. The preferred route for the delivery of antimicrobial drugs is the oral one; oral formulations capable of extending the duration of drug delivery and minimizing side effects have received much attention. The combination of antimicrobial agents with nanomaterials has been seen as a particularly promising strategy to overcome these limitations. Particulate formulations have proven their efficiency in achieving better pharmacokinetic profiles and improving the bio availability of several antibiotics. Antibiotic modified particles have shown their capability to protect some of the antimicrobial drugs from stomach acid and first-pass metabolisms in the gastrointestinal tract. Likewise, particle formulations can increase the circulation times of a drug and the local concentration gradient across absorptive cells. The present review describes the current status of different types of antibiotic loaded nano-systems. Key principles such as antibiotic loading, the release mechanism and the mode of action involved in pathogen killing or inhibition will be discussed in more detail. It is hoped that the general knowledge obtained here will help in the generation of advanced nanomaterials loaded with antimicrobials agents.

Low temperature atmospheric pressure plasma devices are suitable experimental solutions to generate transitory molecular environments with various applications. In this study we present experimental results regarding the plasma chemistry of dielectric barrier discharges (DBD) in helium - hydrogen (0.1%) - hydrocarbons (1.2%) mixtures. Four types of hydrocarbon gases were studied: methane ( CH 4 ), ethane ( C 2 H 6 ), propane ( C 3 H 8 ), and butane ( C 4 H 10 ). Discharge diagnosis and monitoring was assured by electrical measurements and optical emission spectroscopy. Molecular beam mass spectrometry is engaged to sample positive ions populations from two different plasma sources. Dissociation and generation of higher-chain and cyclic (aromatic) hydrocarbons were discussed as a function of feed gas and discharge geometry. We found a strong influence of these parameters on both molecular mass distribution and recombination processes in the plasma volume.

Bacterial infections are one of the leading causes of disease worldwide. Conventional antibiotics are becoming less efficient, due to antibiotic-resistant bacterial strains. Therefore, the development of novel antibacterial materials and advanced treatment strategies are becoming increasingly important. In the present work, we developed a simple and efficient strategy for effective bacterial capture and their subsequent eradication through photothermal killing. The developed device consists of a flexible nanoheater, comprising a Kapton/Au nanoholes substrate, coated with reduced graphene oxide–polyethyleneimine (K/Au NH/rGO–PEI) thin films. The Au NH plasmonic structure was tailored to feature strong absorption in the near-infrared (NIR) region, where most biological matter has limited absorption, while PEI was investigated for its strong binding with bacteria through electrostatic interactions. The K/Au NH/rGO–PEI device was demonstrated to capture and eliminate effectively both planktonic Gram-positive Staphilococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria after 10 min of NIR (980 nm) irradiation and, to destroy and eradicate Staphilococcus epidermidis (S. epidermidis) biofilms after 30 min irradiation. The technique developed herein is simple and universal with potential applications for eradication of different micro-organisms.

High-performance electrode materials consisting of intertwined caterpillar-like NiFe layered double hydroxide bridges coated on reduced graphene oxide modified Ni foam (NiFe LDHs/rGO/NF) were prepared via a facile two-step electrodeposition method. First, rGO was electrochemically coated onto NF at a constant potential of −1.2 V vs. SCE for 600 s. Then NiFe LDHs of different Ni to Fe ratios were electrodeposited onto the formed rGO/NF electrodes at −1.2 V vs. SCE for 10 s. Under optimized conditions, NiFe LDHs/rGO/NF composites displayed a high specific capacitance of 1462.5 F g−1 at a current density of 5 A g−1 and retained about 64.7% of the original capacitance after 2000 cycles. Furthermore, a flexible asymmetric supercapacitor was prepared using NiFe LDHs/rGO/NF as the cathode and mesoporous carbon (MC) coated on NF as the anode. The supercapacitor exhibited an energy density of 17.71 Wh kg−1 at a power density of 348.49 W kg−1. All of these findings suggest that the new electrodes developed in this work hold a potential application prospect in flexible energy storage devices.

International audience; Bacterial infections are causing worldwide morbidity and mortality. One way to limit infectious outbreaks and optimize clinical management of infections is through the development of fast and sensitive sensing of bacteria. Most sensing approaches are currently based on immunological detection principles. We report here on an impedimetric sensor to selectively and sensitive detect uropathogenic E. coli cells (E. coli UTI89) using artificial recognition sites. We show here the possibility to imprint the rod-shape structure of E. coli UTI 89 into ultra-thin inorganic silica coatings on gold electrodes in a reproducible manner. A linear range from to 1 × 10 0-1 × 10 4 cfu mL −1 is obtained. With a detection limit for E. coli UTI89 below 1 cfu mL −1 from five blank signals (95% confidence level) and excellent selective binding capabilities, these bacterial cell imprinted electrodes brings us closer to a low cost specific bacterial recognition surfaces.

In natural environments, the aquatic organisms are exposed to complex mixtures of chemicals which may originate from natural sources or from anthropogenic activities. In this context, the aim of the study was to assess the potential effects that might occur when aquatic organisms are simultaneously exposed to multiple chemicals. For that, we have studied the acute effects of cadmium (0.2 μg L−1), nickel (10 μg L−1) and deltamethrin (2 μg L−1) as individual toxicants and as mixture on the behavioral responses, oxidative stress (SOD and GPx), body electrolytes and trace metals profiles of zebrafish (Danio rerio). So far the scientific literature did not report about the combined effects of pesticides and toxic metals on zebrafish behavior using a 3D tracking system. Compared with other studies, in the present paper we investigated the acute effects of two heavy metals associated with a pesticide on zebrafish, in the range of environmentally relevant concentrations. Thus, the environmental concentrations of cadmium and nickel in three rivers affected by urban activities and one river with protected areas as background control were measured. The observations that resulted in our study demonstrated that deltamethrin toxicity was significantly decreased in some of the behavioral variables and oxidative stress when combined with Cd Ni mixture. Consequently, our study supports previous works concerning the combined toxicity of environmental chemicals since their simultaneous presence in the aqueous environment may lead to higher or lower toxicological effects on biota than those reported from a single pollutant. Therefore, the evaluation of toxic effects of a single contaminant does not offer a realistic estimate of its impact against aqueous ecosystems. This study also supports the idea that the interactions between different chemical compounds which do not exceed the maximum permitted limits in environment may have benefits for aquatic life forms or be more toxic.

International audience; The steady increase in antimicrobial resistance in different 16 pathogens requires the development of alternative treatment strategies 17 next to the oral delivery of antibiotics. A photothermally activated 18 platform based on reduced graphene oxide (rGO)-embedded polymeric 19 nanofiber mats for on-demand release of antibiotics upon irradiation in 20 the near-infrared is fabricated. Cross-linked hydrophilic nanofibers, 21 obtained by electrospinning a mixture of poly(acrylic acid) (PAA) and 22 rGO, show excellent stability in aqueous media. Importantly, these PAA@ 23 rGO nanofiber mats exhibit controlled photothermal heating upon 24 irradiation at 980 nm. Nanofiber mats are efficiently loaded with 25 antibiotics through simple immersion into corresponding antibiotics 26 solutions. Whereas passive diffusion based release at room temperature is 27 extremely low, photothermal activation results in increased release within 28 few minutes, with release rates tunable through power density of the 29 applied irradiation. The large difference over passive and active release, as well as the controlled turn-on of release allows 30 regulation of the dosage of the antibiotics, as evidenced by the inhibition of planktonic bacteria growth. Treatment of superficial 31 skin infections with the antibiotic-loaded nanofiber mats show efficient wound healing of the infected site. Facile fabrication and 32 implementation of these photothermally active nanofiber mats makes this novel platform adaptable for on-demand delivery of 33 various therapeutic agents. 34

The development of efficient water oxidation catalytic interfaces has become a demanding challenge to fulfill the promise of water splitting for clean energy conversion and storage. The present wor...

International audience; Next to graphene nanomaterials, molybdenum disulfide (MoS 2) offers large surface area that can enhance its biosensing performance. In this work, we investigate the performance of glassy carbon (GC) electrodes modified successively with porous reduced graphene oxide (prGO) and molybdenum sulfide (MoS 2) for the sensitive and selective detection of the L1-major capsid protein of human papilloma virus (HPV). Owing to the difficulties to perform serological assays and HPV cultures efficiently, tools based on molecular recognition are becoming of great importance. We developed here an electrochemical sensor for HPV upon covalent functionalization of the electrode with an aptamer Sc5-c3, a RNA aptamer targeted against the HPV-16 L1 protein. Using differential pulse voltammetry (DPV) and an optimized To whom correspondence should be send to: sabine.szunerits@univ-lille.fr

Fast, reliable and selective detection of microorganisms is of uttermost importance in clinical analysis, but also in food and water quality monitoring. In this study, we report on the construction of an immunosensor for sensitive and selective electrochemical detection of uropathogenic Escherichia coli (E. coli) UTI89 bacteria in aqueous and serum samples. We took benefit of electrophoretic deposition (EPD) to prepare, in a simple, controllable and cost effective way, gold electrodes modified with thin active layers of reduced graphene oxide/polyethylenimine (rGO/PEI). While rGO exhibits high surface area and favourable electrochemical properties, the presence of abundant single bondNH2 groups on PEI offers a plethora of opportunities for the sensor’s surface functionalization. To achieve selectivity of detection, the electrode surface was covalently modified with anti-fimbrial E. coli antibodies via amide bond formation. To minimize non-specific adsorption, the immunosensor was additionally modified with pyrene-polyethyleneglycol (pyrene-PEG) moieties prior to antibody immobilization. The detection of E. coli was based on the restriction of electron transfer of a redox mediator, in our case potassium ferrocyanide, to the rGO/PEI modified electrical transducer due to the formation of an immune complex. The developed immunosensor displayed a sigmoidal shape with a linear range of 1 × 101–1 × 104 cfu mL−1 (R2 = 0.995) according to i(μA) = −16.66–20.5 × log[E. coli] (cfu mL−1) and a detection limit of 10 cfu mL−1. Additionally, the sensor performed well both in aqueous, serum and urine media, which is essential for its potential use for clinical diagnosis of pathogenic diseases. Selectivity studies showed that the immunosensor was able to discriminate between E. coli UTI89 wild-type strain and UTI89 Δfim, without fim operon. 260

Plasma polymerized styrene (pPS) films were successfully synthesized by means of an atmospheric pressure plasma technique, using a mixture of argon gas and styrene vapor. The morphology and film thickness of the pPS films, deposited on 1 min argon plasma pre-treated glass substrates, were smooth and uniform without any visible features across the whole length of the substrates, and the films displayed a water contact angle of ∼83°. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) analysis confirmed the presence of oxygen-containing groups and the intact aromatic ring in the pPS coating. The obtained pPS films were stable for at least 30 days in air without any visible morphological degradation or chemical changes. However, the formation of a topographical pattern with micrometer lateral size and nanometer depth level was observed upon immersion in aqueous media for 72 hours. Micropore formation was believed to originate from the solubility of low cross-linked oligomers and their subsequent extraction in aqueous media. The influence of the microstructured pPS surface in mediating the attachment of eukaryotic and prokaryotic cells was further investigated. The micro-structured pPS surface influenced the adhesion and proliferation of mammalian cells. Furthermore, we could demonstrate that these films were efficient in the prevention of Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus epidermidis (S. epidermis) adhesion and biofilm formation. Importantly, the viability of non-adherent cells and of planktonic bacteria was not affected. Post-coating of the microstructured pPS with biocompatible polydopamine did not impact on the antibacterial properties of the surface, suggesting that the polymer topography was the dominant factor. The non-biocidal pPS coating can be useful in applications where micro-organism colonization and biofilm formation need to be prevented, such as food packaging and medical equipment.

Advances in nanotechnology have seen the development of several microbiocidal nanoparticles displaying activity against biofilms. These applications benefit from one or more combinations of the nanoparticle properties. Nanoparticles may indeed concentrate drugs on their surface resulting in polyvalent effects and improved efficacy to fight against bacteria. Nanodiamonds (NDs) are among the most promising new materials for biomedical applications. We elucidate in this paper the effect of menthol modified nanodiamond (ND-menthol) particles on bacterial viability against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. We show that while ND-menthol particles are non-toxic to both pathogens, they show significant antibiofilm activity. The presence of ND-menthol particles reduces biofilm formation more efficiently than free menthol, unmodified oxidized NDs and ampicillin, a commonly used antibiotic. Our findings might be thus a step forward towards the development of alternative non antibiotic based strategies targeting bacterial infections.

International audience; Microsystems play an important role in many biological and environmental applications. The integration of electrical interfaces into such miniaturized systems provides new opportunities for electrochemical sensing where high sensitivity and selectivity towards the analyte are requested. This can be only achieved upon controlled functionalization of the working electrode, a challenge for compact microsystems. In this work, we demonstrate the benefit of electrophoretic deposition (EPD) of reduced graphene oxide/polyethylenimine (rGO/ PEI) for the selective modification of a gold (Au) microelectrode in a microsystem comprising a Pt counter and a Ag/AgCl reference electrode. The functionalized microsystem was successfully applied for the sensing of dopamine with a detection limit of 50 nM. Additionally, the microsystem exhibited good performance for the detection of dopamine levels in meat samples.

Low temperature plasma jets gained increased interest in the last years as a potential device in many life science applications, including here human or veterinary medicine. Standardisation of plasma sources and biological protocols are necessary for quality assurance reasons, due to the fact that this type of atmospheric pressure plasma source is available in multiple configurations and their operational parameters span also on a broad range of items, such as all characteristics of high voltage pulses used for gas breakdown, geometrical characteristics, gas feed composition and conductive or biological target characteristics. In this paper we present results related to electrical, optical and molecular beam mass spectrometry diagnosis of a helium plasma jet, emphasising the influence of various operational parameters of the high voltage pulses on plasma jet properties. Discussion on physical parameters that influence the biological response is included, together with important results on plasma sources statistical behaviour until reaching a quasi-stationary working regime. The warm-up period of the plasma jet, specific to many other plasma sources, must be precisely known and specified whenever the plasma jets are used as a tool for life science applications.

International audience; Despite the advantages of an electrochemical control for drug release, only a handful of electrochemical-based release systems have been developed so far. We report herein on the development of an electrochemically activatable platform for on-demand delivery of drugs. It is based on flexible gold thin film electrodes coated with porous reduced graphene oxide (prGO) nanosheets onto which the drug of interest has been integrated beforehand. Two different drugs are investigated here: ondansetron hydrochloride (ODS), a selective 5-HT3 receptor antagonist used for preventing nausea and vomiting caused by chemotherapy and radiotherapy, and ampicillin (AMP), an antibiotic to prevent and treat a number of bacterial infections such as respiratory tract infections, urinary tract infections, and meningitis. In the case of ODS, application of a negative potential bias of −0.8 V results in a sustained slow ODS release with an ODS flux of 47 μg cm−2 h−1. In the case of AMP, we show that polyethyleneimine modified prGO (prGO/PEI) is an extremely efficient matrix. Upon the application of +0.8 V, 24% of AMP could be released from the electrical interface in a time span of 2 h. The released AMP kept its antibacterial activity as demonstrated by antimicrobial tests. These examples illustrate the major benefits of the developed approach for biomedical applications.

International audience; The fast and efficient elimination of pathogenic bacteria from water, food or biological samples such as blood remains a challenging task. Magnetic isolation of bacteria from complex media holds particular promise for water disinfection and other biotechnological applications employing bacteria. When it comes to infectious diseases such as urinary tract infections, the selective removal of the pathogenic species in complex media such as human serum is also of importance. This issue can only be accomplished by adding pathogen specific targeting sites onto the magnetic nanostructures. In this work, we investigate the potential of 2-nitrodopamine modified magnetic particles anchored on reduced graphene oxide (rGO) nanocomposites for rapid capture and efficient elimination of E. coli associated with urinary tract infections (UTIs) from water and serum samples. An optimized magnetic nanocarrier achieves a 99.9% capture efficiency even at E. coli concentrations of 1 × 10 1 cfu mL −1 in 30 min. In addition, functionalization of the nanostructures with poly(ethylene glycol) modified pyrene units and anti-fimbrial E. coli antibodies allowed specific elimination of E. coli UTI89 from serum samples. Irradiation of the E. coli loaded nanocomposite with a near-infrared laser results in the total ablation of the captured pathogens. This method can be flexibly modified for any other pathogenic bacteria, depending on the antibodies used, and might be an interesting alternative material for a magnetic-based body fluid purification approach.

A 980nm laser-driven antimicrobial photothermal therapy using poly(vinylpyrrolidone) -coated Prussian Blue nanoparticles (PVP/PB NPs) is demonstrated. This approach allows an efficient eradication of a virulent strain of Gram-negative Escherichia coli (E. coli) associated with urinary tract infection as well as for the ablation of antibiotic resistant pathogens such as methicillin resistant Staphylococcus aureus (MRSA) and extended spectrum β-lactamase (ESBL) E. coli. Interestingly the 980nm irradiation exhibits minimal effect on mammalian cells up to a PVP/PB NPs concentration of 50μgmL(-1), while at this concentration bacteria are completely eradicated. This feature is certainly very promising for the selective targeting of bacteria over mammalian cells.

Atmospheric pressure DC-driven self-pulsing transient spark (TS) discharge operated in air and pulse-driven dielectric barrier discharge plasma jet (PJ) operated in helium in contact with water solutions were used for inducing chemical effects in water solutions, and the treatment of bacteria (Escherichia coli), mammalian cells (Vero line normal cells, HeLa line cancerous cells), deoxyribonucleic acid (dsDNA), and protein (bovine serum albumin). Two different methods of water solution supply were used in the TS: water electrode system and water spray system. The effects of both TS systems and the PJ were compared, as well as a direct exposure of the solution to the discharge with an indirect exposure to the discharge activated gas flow. The chemical analysis of water solutions was performed by using colorimetric methods of UV-VIS absorption spectrophotometry. The bactericidal effects of the discharges on bacteria were evaluated by standard microbiological plate count method. Viability, apoptosis and cell cycle were assessed in normal and cancerous cells. Viability of cells was evaluated by trypan blue exclusion test, apoptosis by Annexin V-FITC/propidium iodide assay, and cell cycle progression by propidium iodide/RNase test. The effect of the discharges on deoxyribonucleic acid and protein were evaluated by fluorescence and UV absorption spectroscopy. The results of bacterial and mammalian cell viability, apoptosis, and cell cycle clearly show that cold plasma can inactivate bacteria and selectively target cancerous cells, which is very important for possible future development of new plasma therapeutic strategies in biomedicine. The authors found that all investigated bio-effects were stronger with the air TS discharge than with the He PJ, even in indirect exposure.

Non-thermal plasma jets at atmospheric pressure are useful tools nowadays in plasma medicine. Various applications are tested such as cauterization, coagulation, wound healing, natural and artificial surfaces decontamination, and sterilization. In order to know more about the effects of gas plasma on biological supramolecules, we exposed protein powders to a barrier discharge helium plasma jet. Then, spectroscopic investigations were carried out in order to obtain information on protein secondary, tertiary, and quaternary structures. We obtained a reduction of the protein alpha-helix content after the plasma exposure and a different behavior, for both thermal denaturation/renaturation kinetics and thermal aggregation process.

International audience; A wide range of biomedical materials have been proposed to meet the different needs for controlled oral or intravenous drug delivery. The advantages of oral delivery such as self-administration of a predetermined drug dose at defined time intervals makes it the most convenient means for the delivery of small molecular drugs. It fails however to delivery therapeutic macromolecules due to rapid degradation in the stomach and size-limited transport across the epithelium. The primary mode of administration of macromolecules is presently via injection. This administration mode is not without limitations, as the invasive nature of injections elicits pain and decreases patients' compliance. Alternative routes for drug delivery have been looked for, one being the skin. Delivery of drugs via the skin is based on the therapeutics penetrating the stratum corneum with the advantage of overcoming first-pass metabolism of drugs, to deliver drugs with a short-half-life time more easily and to eliminate frequent administrations to maintain constant drug delivery. The transdermal market still remains limited to a narrow range of drugs. The low permeability of the SC to water-soluble and macromolecular drugs poses significant challenges to transdermal administering via passive diffusion through the skin, as is the case for all topically administered drug formulations intended to bring the therapeutic into the general circulation. To widen the scope of drugs for transdermal delivery, new procedures to enhance skin permeation to hydrophilic drugs and macromolecules are under development. Next to the integration of skin enhancers into pharmaceutical formulations, nanoparticles based on lipid carrier have been widely considered and reviewed. While being briefly reviewed here, the main focus of this article is on current advancements using polymeric and metallic nanoparticles. Next to these passive technologies, the handful of active technologies for local and systemic transdermal drug delivery will be discussed and put into perspective. While passive approaches dominate the literature and the transdermal market, active delivery patches based on microneedles or iontophoresis approaches have shown great promise for transdermal drug delivery and have entered the market, in the last decade. This review gives an overall idea of the current activities in this field.