Ion exchange based approach for rapid and selective Pb(II) removal using iron oxide decorated metal organic framework hybrid.

Polyacrylic acid capped Fe3O4 - Cu-MOF (i-MOF) hybrid was prepared for rapid and selective lead removal, with 93% removal efficiency, exceptional selectivity, and adsorption capacity of 610 mg/g and 91% of i-MOF hybrid could be easily separated from the contaminated water using magnetic separation. The adsorption process followed a pseudo-second-order model and the adsorption efficiency decreased from 93% to 83% on raising the temperature from 25 °C to 40 °C. The change in equilibrium adsorption capacity with respect to equilibrium adsorbate concentration followed the Langmuir isotherm model. i-MOF had a high selectivity coefficient and removal efficiency for lead ions even when exposed simultaneously with naturally abundant cations (Na(I), Ca(II), Mg(II)). Release of Cu(II) ions from the i-MOF after Pb(II) removal suggested suggested ion-exchange to be the dominant removal mechanism. This new finding for Pb(II) removal with excellent adsorption performance using i-MOF through ion exchange based approach is a viable option for treating lead contaminated water.

Pan-European inter-laboratory studies on a panel of in vitro cytotoxicity and pro-inflammation assays for nanoparticles.

The rapid development of nanotechnologies and increased production and use of nanomaterials raise concerns about their potential toxic effects for human health and environment. To evaluate the biological effects of nanomaterials, a set of reliable and reproducible methods and development of standard operating procedures (SOPs) is required. In the framework of the European FP7 NanoValid project, three different cell viability assays (MTS, ATP content, and caspase-3/7 activity) with different readouts (absorbance, luminescence and fluorescence) and two immune assays (ELISA of pro-inflammatory cytokines IL1-ß and TNF-α) were evaluated by inter-laboratory comparison. The aim was to determine the suitability and reliability of these assays for nanosafety assessment. Studies on silver and copper oxide nanoparticles (NPs) were performed, and SOPs for particle handling, cell culture, and in vitro assays were established or adapted. These SOPs give precise descriptions of assay procedures, cell culture/seeding conditions, NPs/positive control preparation and dilutions, experimental well plate preparation, and evaluation of NPs interference. The following conclusions can be highlighted from the pan-European inter-laboratory studies: Testing of NPs interference with the toxicity assays should always be conducted. Interference tests should be designed as close as possible to the cell exposure conditions. ATP and MTS assays gave consistent toxicity results with low inter-laboratory variability using Ag and CuO NPs and different cell lines and therefore, could be recommended for further validation and standardization. High inter-laboratory variability was observed for Caspase 3/7 assay and ELISA for IL1-ß and TNF-α measurements.

Bioaccumulation and toxicity of CuO nanoparticles by a freshwater invertebrate after waterborne and dietborne exposures.

The incidental ingestion of engineered nanoparticles (NPs) can be an important route of uptake for aquatic organisms. Yet, knowledge of dietary bioavailability and toxicity of NPs is scarce. Here we used isotopically modified copper oxide ((65)CuO) NPs to characterize the processes governing their bioaccumulation in a freshwater snail after waterborne and dietborne exposures. Lymnaea stagnalis efficiently accumulated (65)Cu after aqueous and dietary exposures to (65)CuO NPs. Cu assimilation efficiency and feeding rates averaged 83% and 0.61 g g(-1) d(-1) at low exposure concentrations (<100 nmol g(-1)), and declined by nearly 50% above this concentration. We estimated that 80-90% of the bioaccumulated (65)Cu concentration in L. stagnalis originated from the (65)CuO NPs, suggesting that dissolution had a negligible influence on Cu uptake from the NPs under our experimental conditions. The physiological loss of (65)Cu incorporated into tissues after exposures to (65)CuO NPs was rapid over the first days of depuration and not detectable thereafter. As a result, large Cu body concentrations are expected in L. stagnalis after exposure to CuO NPs. To the degree that there is a link between bioaccumulation and toxicity, dietborne exposures to CuO NPs are likely to elicit adverse effects more readily than waterborne exposures.

Multi-walled carbon nanotube length as a critical determinant of bioreactivity with primary human pulmonary alveolar cells.

Multiwalled carbon nanotube (MWCNT) length is suggested to critically determine their pulmonary toxicity. This stems from in vitro and in vivo rodent studies and in vitro human studies using cell lines (typically cancerous). There is little data using primary human lung cells. We addressed this knowledge gap, using highly relevant, primary human alveolar cell models exposed to precisely synthesized and thoroughly characterized MWCNTs. In this work, transformed human alveolar type-I-like epithelial cells (TT1), primary human alveolar type-II epithelial cells (ATII) and alveolar macrophages (AM) were treated with increasing concentrations of MWCNTs before measuring cytotoxicity, inflammatory mediator release and MAP kinase signalling. Strikingly, we observed that short MWCNTs (~0.6 µm in length) induced significantly greater responses from the epithelial cells, whilst AM were particularly susceptible to long MWCNTs (~20 µm). These differences in the pattern of mediator release were associated with alternative profiles of JNK, p38 and ERK1/2 MAP kinase signal transduction within each cell type. This study, using highly relevant target human alveolar cells and well defined and characterized MWCNTs, shows marked cellular responses to the MWCNTs that vary according to the target cell type, as well as the aspect ratio of the MWCNT.

Multiple cytotoxic and genotoxic effects induced in vitro by differently shaped copper oxide nanomaterials.

In nanotoxicology, the capacity of nanoparticles of the same composition but different shape to induce cytotoxicity and genotoxicity is largely unknown. A series of cytotoxic and genotoxic responses following in vitro exposure to differently shaped CuO nanoparticles (CuO NPs, mass concentrations from 0.1 to 100 µg/ml) were assessed in murine macrophages RAW 264.7 and in peripheral whole blood from healthy volunteers. Cytotoxicity, cytostasis and genotoxicity were evaluated by the colorimetric assay of formazan reduction [3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT)] and by the cytokinesis-block micronucleus cytome (CBMN Cyt) assay. The comet assay was applied for detecting DNA strand breaks and information on oxidative damage to DNA (oxidised purines and pyrimidines). The MTT assay revealed a decrease in cell viability in RAW 264.7 cells and peripheral blood lymphocytes (PBL) with significant dose-effect relationships for the different CuO NP shapes. The comet assay revealed a dose-dependent increase in primary DNA damage, and a significant increase in oxidative damage to DNA was also detectable, as well as increased frequency of micronuclei in binucleated cells, often in a dose-related manner. Proliferative activity, cytotoxicity and apoptotic markers showed a significant trend in the two cell types. Finally, we have differentiated clastogenic events from aneugenic events by fluorescence in situ hybridisation with human and murine pancentromeric probes, revealing for the first time characteristic aneugenic responses related to the shape of CuO NPs and cell type. Independently of size and shape, all CuO NPs revealed a clear-cut cytotoxic and genotoxic potential; this suggests that CuO NPs are good candidates for positive controls in nanotoxicology.

Enhanced therapeutic action of Trastuzumab loaded ZnxMn1-xFe2O4 nanoparticles using a pre-treatment step for hyperthermia treatment of HER2+ breast cancer.

In this study, Ferrites (Fe3O4, MnFe2O4, ZnFe2O4) and different stoichiometric ratios of ZnxMn1-xFe2O4 (x = 0.2, 0.4, 0.6, and 0.8) nanoparticles (<15 nm) were synthesized by microwave-assisted method and optimised for hyperthermia studies. The selection of the optimised variant of ferrite i.e. Zn0.4Mn0.6Fe2O4 was found to be the best variant based on VSM (38.14 emu g-1) hyperthermia-based temperature rise (maximum ΔT of 38 °C), SAR and ILP values. Trastuzumab, which is known to bind with HER2 receptors of breast cancer was chemically tethered onto Zn0.4Mn0.6Fe2O4 nanoparticles through EDC/NHS coupling with a loading efficiency of 80%. The attached Trastuzumab aided during the pre-treatment step by aiding in the internalisation of Zn0.4Mn0.6Fe2O4 nanoparticles, with cellular uptake of 11% in SK-BR-3 (cancerous HER2+) cells compared to ∼5% for MDA-MB-231 (cancerous HER2-) and RPE-1 (non-cancerous) cells. In the presence of a hyperthermia trigger for 15 mins, ZnxMn1-xFe2O4 -Trastuzumab formulation had a maximum therapeutic effect by reducing the SK-BR-3 cell viability to 14% without adversely affecting the RPE-1 cells. The mechanism of ZnxMn1-xFe2O4-Trastuzumab combination was examined using an internalisation study, MTT-based viability, proliferation study, and ROS generation assay. By utilizing both Trastuzumab and hyperthermia, we achieve their synergistic anticancer properties while minimizing the drug requirement and reducing any effect on non-cancerous cells.

Isotopically modified nanoparticles for enhanced detection in bioaccumulation studies.

This work presents results on synthesis of isotopically enriched (99% (65)Cu) copper oxide nanoparticles and its application in ecotoxicological studies. (65)CuO nanoparticles were synthesized as spheres (7 nm) and rods (7 × 40 nm). Significant differences were observed between the reactivity and dissolution of spherical and rod shaped nanoparticles. The extreme sensitivity of the stable isotope tracing technique developed in this study allowed determining Cu uptake at exposure concentrations equivalent to background Cu concentrations in freshwater systems (0.2-30 µg/L). Without a tracer, detection of newly accumulated Cu was impossible, even at exposure concentrations surpassing some of the most contaminated water systems (>1 mg/L).

Bioaccumulation dynamics and modeling in an estuarine invertebrate following aqueous exposure to nanosized and dissolved silver.

Predicting the environmental impact of engineered nanomaterials (ENMs) is increasingly important owing to the prevalence of emerging nanotechnologies. We derived waterborne uptake and efflux rate constants for the estuarine snail, Peringia ulvae, exposed to dissolved Ag (AgNO(3)) and silver nanoparticles (Ag NPs), using biodynamic modeling. Uptake rates demonstrated that dissolved Ag is twice as bioavailable as Ag in nanoparticle form. Biphasic loss dynamics revealed the faster elimination of Ag from Ag NPs at the start of depuration, but similar slow efflux rate constants. The integration of biodynamic parameters into our model accurately predicted Ag tissue burdens during chronic exposure with 85% of predicted values within a factor of 2 of observed values. Zeta potentials for the Ag NPs were lower in estuarine waters than in waters of less salinity; and uptake rates in P. ulvae were slower than reported for the freshwater snail Lymnaea stagnalis in similar experiments. This suggests aggregation of Ag NPs occurs in estuarine waters and reduces, but does not eliminate, bioavailability of Ag from the Ag NPs. Biodynamic modeling provides an effective methodology to determine bioavailable metal concentrations (originating from metal and metal-oxide nanoparticles) in the environment and may aid future ENM risk assessment.

Toxicological Impact and in Vivo Tracing of Rhodamine Functionalised ZIF-8 Nanoparticles.

Metal Organic Frameworks (MOFs) are extensively used for a wide range of applications due to their exceptionally high surface area. MOF particles are conventionally in micron size, but the nanosized MOFs show good transportation/mobility due to their small size, and when combined with the high surface area of MOFs, it makes MOF nanoparticles an ideal candidate to study for environmental remediation. Therefore, it is important to study the ecotoxicological impact of these MOFs. In this study, we developed rhodamine labelled nanoparticles of zinc imidazolate metal organic framework (ZIF-8 MOFs) as a means of in vivo tracing the MOF translocation in C. elegans. Rhodamine B isothiocyanate functionalized ZIF-8 MOFs nanoparticles (RBITC@ZIF-8 MOF nanoparticles; size 44 ± 7 nm) were fed to the worms naturally within a concentration range of 0.16-16.4 µg mg-1. Fluorescence was detected in the pharyngeal and gut lumen regions of the worms after 4 h of treatment, for exposure concentrations >0.163 µg mg-1. A higher intensity of fluorescence was observed at the end of 24 h for all exposure concentrations. Worms treated with RBITC@ZIF-8 MOF concentrations of ≥1.63 µg mg-1 for 24 h showed a bright stable fluorescence signal at the tail region. The uptake of RBITC@ZIF-8 MOF for an exposure concentration of 0.163, 1.63, and 8.2 µg mg-1 was found to be 52.1, 11.4 and 28.6%, respectively. Through this study, we showed that RBITC@ZIF-8 MOFs can be exposed to C. elegans and imaged at low concentrations of ∼0.16 µg mg-1.

Microwave-assisted synthesis and upconversion luminescence of NaYF4:Yb, Gd, Er and NaYF4:Yb, Gd, Tm nanorods.

Anisotropic rare earth ion (RE3+) doped fluoride upconversion particles are emerging as potential candidate in diverse areas, ranging from biomedical imaging to photonics. Here, we develop a facile strategy to synthesize NaYF4: Yb, Gd, Er, and NaYF4: Yb, Gd, Tm upconversion nanorods via microwave synthesis route by controlling the synthesis time and compared the optical properties similar nanorods prepared via solvothermal technique. With the increase in synthesis time, the phase of the particle found to change from mixed phase to purely hexagonal and morphology of the particles change mixed phase of spherical and rod-shaped particles to completely nanorods for a synthesis time of 60 min. Further, the intrinsically hydrophobic particles changed to hydrophilic by removal of oleic capping via acid treatment and the amine functionalized silica coating. The upconversion luminescence as well as laser power dependent emission properties of the surface modified particles elucidate that surface modification route influence the upconversion luminescence as well as solvent dependent emission properties. Moreover, the laser power dependent studies elucidate that the upconversion process in a multi-photon process.

Novel dual labelled nanoprobes for nanosafety studies: Quantification and imaging experiment of CuO nanoparticles in C. elegans.

Metal oxide nanoparticles have been extensively studied for their toxicological impacts. However, accurate tracing/quantification of the nanomaterials and their biological responses are difficult to measure at low concentrations. To overcome the challenge, we developed a dual-labelling technique of CuO nanoparticles with a stable isotope of 65Cu, and with rhodamine dye. In vivo experiments on C. elegans were performed using natural feeding of Rhodamine B isothiocyanate-(3 aminopropyl) triethoxysilane functionalized 65CuO nanoprobes (RBITC-APTES@65CuO) (size = 7.41 ± 1 nm) within the range of Predicted Environmental Concentration (PEC) of CuO nanoparticles in soil and sediments. Fluorescence emission (570 nm) was detected in the lumen of the intestine and the pharynx of C. elegans with no impact of nanoparticle exposure on the brood size and life span of worms. The ingested fluorescent labelled RBITC-APTES@65CuO nanoprobes did not enter the reproductive system and were distributed in the alimentary canal of C. elegans. Strong fluorescent signals from the ingested RBITC-APTES@65CuO nanoprobes were achieved even after 24 h of exposure demonstrating the high stability of these nanoprobes in vivo. The net accumulation measured of 65Cu in C. elegans after background subtraction was 0.001 µg mg-1 (3.52 %), 0.005 µg mg-1 (1.76 %) and 0.024 µg mg-1 (1.69 %) for an exposure concentration of 0.0284 µg mg-1, 0.284 µg mg-1, and 1.42 µg mg-1 of 65Cu, respectively. Using C. elegans as a model organism, we demonstrated that RBITC-APTES tagged 65CuO nanoparticles acted as novel nanoprobes for measuring the uptake, accumulation, and biodistribution through quantification and imaging the nanoprobes at a very low exposure concentration (65CuO concentration: 0.033 µg mg-1).

Silver bioaccumulation dynamics in a freshwater invertebrate after aqueous and dietary exposures to nanosized and ionic Ag.

We compared silver (Ag) bioavailability and toxicity to a freshwater gastropod after exposure to ionic silver (Ag(+)) and to Ag nanoparticles (Ag NPs) capped with citrate or with humic acid. Silver form, exposure route, and capping agent influence Ag bioaccumulation dynamics in Lymnaea stagnalis. Snails efficiently accumulated Ag from all forms after either aqueous or dietary exposure. For both exposure routes, uptake rates were faster for Ag(+) than for Ag NPs. Snails efficiently assimilated Ag from Ag NPs mixed with diatoms (assimilation efficiency (AE) ranged from 49 to 58%) and from diatoms pre-exposed to Ag(+) (AE of 73%). In the diet, Ag NPs damaged digestion. Snails ate less and inefficiently processed the ingested food, which adversely impacted their growth. Loss rates of Ag were faster after waterborne exposure to Ag NPs than after exposure to dissolved Ag(+). Once Ag was taken up from diet, whether from Ag(+) or Ag NPs, Ag was lost extremely slowly. Large Ag body concentrations are thus expected in L. stagnalis after dietborne exposures, especially to citrate-capped Ag NPs. Ingestion of Ag associated with particulate materials appears as the most important vector of uptake. Nanosilver exposure from food might trigger important environmental risks.

Cellular internalization of silver nanoparticles in gut epithelia of the estuarine polychaete Nereis diversicolor.

Silver nanoparticles (AgNPs) are widely used which may result in environmental impacts, notably within aquatic ecosystems. As estuarine sediments are sinks for numerous pollutants, but also habitat and food for deposit feeders such as Nereis diversicolor, ingested sediments must be investigated as an important route of uptake for NPs. N. diversicolor were fed sediment spiked with either citrate capped AgNPs (30 ± 5 nm) or aqueous Ag for 10 days. Postexposure AgNPs were observed in the lumen of exposed animals, and three lines of evidence indicated direct internalization of AgNPs into the gut epithelium. With TEM, electron-dense particles resembling AgNPs were observed associated with the apical plasma membrane, in endocytotic pits and in endosomes. Energy dispersive X-ray analysis (EDX) confirmed the presence of Ag in these particles, which were absent in controls. Subcellular fractionation revealed that Ag accumulated from AgNPs was predominantly associated with inorganic granules, organelles, and the heat denatured proteins; whereas dissolved Ag was localized to the metallothionein fraction. Collectively, these results indicate separate routes of cellular internalization and differing in vivo fates of Ag delivered in dissolved and NP form. For AgNPs an endocytotic pathway appears to be a key route of cellular uptake.

Transformation in band energetics of CuO nanoparticles as a function of solubility and its impact on cellular response.

Nanoparticles under a reactive microenvironment, have the propensity to undergo morphological and compositional changes, which can translate into band edge widening. Although cell membrane depolarization has been linked with the electronic band structure of nanomaterials in their native state, the change in band structure as a consequence of a soluble nanoparticle system is less studied. Therefore we studied the consequence of dissolution of CuO nanoparticles on the band structure and flat band potentials and correlated it with its ability to induce a intracellular oxidative stress. The temporal variation in bandgap, fermi energy level and valence band maxima were evaluated on the remnant CuO nanoparticles post dissolution. CuO nanoparticles showed a very high dissolution in simulated body fluid (51%) and cell culture media (75%). This dissolution resulted in an in situ physico-chemical transformation of CuO nanoparticles. A temporal increase in the bandgap energy as a result of media interaction was up to 107%. Temporal variation in the flat band potentials with the generation of intracellular ROS, cell viability, late and early apoptosis in addition to necrosis on RAW 264.7 cells was established due to biological redox potential overlap. The mRNA expression for TNF-α, IL-6, IL-1ß and IL-10 in response to the particle treatment was also evalulated for 6 hours. Through this study, we establish that the toxicological potential of CuO nanoparticles is a temporal function of band energies (its overlap with the intracellular redox potential) followed by release of ionic species in the cytotoxic regime.

Characterisation of carbon nanotubes in the context of toxicity studies.

Nanotechnology has the potential to revolutionise our futures, but has also prompted concerns about the possibility that nanomaterials may harm humans or the biosphere. The unique properties of nanoparticles, that give them novel size dependent functionalities, may also have the potential to cause harm. Discrepancies in existing human health and environmental studies have shown the importance of good quality, well-characterized reference nanomaterials for toxicological studies.Here we make a case for the importance of the detailed characterization of nanoparticles, using several methods, particularly to allow the recognition of impurities and the presence of chemically identical but structurally distinct phases. Methods to characterise fully, commercially available multi-wall carbon nanotubes at different scales, are presented.

Incorporation of vitamin E in poly(3hydroxybutyrate)/Bioglass composite films: effect on surface properties and cell attachment.

This study investigated the possibility of incorporating alpha-tocopherol (vitamin E) into poly(3hydroxybutyrate) (P(3HB))/Bioglass composites, which are being developed for bone tissue engineering matrices. P(3HB) films with 20 wt% Bioglass and 10 wt% vitamin E were prepared using the solvent casting technique. Addition of vitamin E significantly improved the hydrophilicity of the composites along with increasing the total protein adsorption. The presence of protein adsorbed on the composite surface was further confirmed using X-ray photoelectron spectroscopy analysis. Preliminary cell culture studies using MG-63 human osteoblasts showed that the addition of vitamin E in the P(3HB)/20 wt% Bioglass films significantly increased cell proliferation. The results achieved in this study confirmed the possibility of incorporating vitamin E as a suitable additive in P(3HB)/Bioglass composites to engineer the surface of the composites by promoting higher protein adsorption and increasing the hydrophilicity.

Montmorillonite clay and humic acid modulate the behavior of copper oxide nanoparticles in aqueous environment and induces developmental defects in zebrafish embryo.

Copper oxide nanoparticles (CuO NPs) is one of the most commonly used metal oxide nanoparticles for commercial and industrial products. An increase in the manufacturing and use of the CuO NPs based products has increased the likelihood of their release into the aquatic environment. This has attracted major attention among researchers to explore their impact in human as well as environmental systems. CuO NPs, once released into the environment interact with the biotic and abiotic constituents of the ecosystem. Hence the objective of the study was to provide a holistic understanding of the effect of abiotic factors on the stability and aggregation of CuO NPs and its correlation with their effect on the development of zebrafish embryo. It has been observed that the bioavailability of CuO NPs decrease in presence of humic acid (HA) and heteroagglomeration of CuO NPs occurs with clay minerals. CuO NPs, CuO NPs + HA and CuO NPs + Clay significantly altered the expression of genes involved in development of dorsoventral axis and neural network of zebrafish embryos. However, the presence of HA with clay showed protective effect on zebrafish embryo development. These findings provide new insights into the interaction of NPs with abiotic factors and combined effects of such complexes on developing zebrafish embryos genetic markers.

Comparison of nanoscale and microscale bioactive glass on the properties of P(3HB)/Bioglass composites.

This study compares the effects of introducing micro (m-BG) and nanoscale (n-BG) bioactive glass particles on the various properties (thermal, mechanical and microstructural) of poly(3hydroxybutyrate) (P(3HB))/bioactive glass composite systems. P(3HB)/bioactive glass composite films with three different concentrations of m-BG and n-BG (10, 20 and 30 wt%, respectively) were prepared by a solvent casting technique. The addition of n-BG particles had a significant stiffening effect on the composites, modulus when compared with m-BG. However, there were no significant differences in the thermal properties of the composites due to the addition of n-BG and m-BG particles. The systematic addition of n-BG particles induced a nanostructured topography on the surface of the composites, which was not visible by SEM in m-BG composites. This surface effect induced by n-BG particles considerably improved the total protein adsorption on the n-BG composites compared to the unfilled polymer and the m-BG composites. A short term in vitro degradation (30 days) study in simulated body fluid (SBF) showed a high level of bioactivity as well as higher water absorption for the P(3HB)/n-BG composites. Furthermore, a cell proliferation study using MG-63 cells demonstrated the good biocompatibility of both types of P(3HB)/bioactive glass composite systems. The results of this investigation confirm that the addition of nanosized bioactive glass particles had a more significant effect on the mechanical and structural properties of a composite system in comparison with microparticles, as well as enhancing protein adsorption, two desirable effects for the application of the composites in tissue engineering.

Tailoring of physicochemical properties of nanocarriers for effective anti-cancer applications.

Nanotechnology has emerged strongly as a viable option to overcome the challenge of early diagnosis and effective drug delivery, for cancer treatment. Emerging research articles have expounded the advantages of using a specific type of nanomaterial-based system called as "nanocarriers," for anti-cancer therapy. The nanocarrier system is used as a transport unit for targeted drug delivery of the therapeutic drug moiety. In order for the nanocarriers to be effective for anticancer therapy, their physicochemical parameter needs to be tuned so that bio-functionalisation can be achieved to (1) allow drugs being attached to the substrate and for their controlled release, (2) ensure the stability of the nanocarrier up to the point of delivery, and (3) clearance of the nanocarrier after the delivery. It is therefore envisaged that tailoring of the physicochemical properties of nanocarriers can greatly influence their reactivity and interaction in the biological milieu, and this is becoming an important parameter for increasing the efficacy of cancer therapy. This review emphasizes the importance of physicochemical properties of nanocarriers, and how they influence its usage as chemotherapeutic drug carriers. The goal of this review is to present a correlation between the physicochemical properties of the nanocarriers and its intended action, and how their design based on these properties can enhance their cancer combating abilities while minimizing damage to the healthy tissues. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2906-2928, 2017.

Electrophoretic deposition of organic/inorganic composite coatings containing ZnO nanoparticles exhibiting antibacterial properties.

To address one of the serious problems associated with permanent implants, namely bacterial infections, novel organic/inorganic coatings containing zinc oxide nanoparticles (nZnO) are proposed. Coatings were obtained by electrophoretic deposition (EPD) on stainless steel 316L. Different deposition conditions namely: deposition times in the range 60-300s and applied voltage in the range 5-30V as well as developing a layered coating approach were studied. Antibacterial tests against gram-positive Staphylococcus aureus and gram-negative Salmonella enteric bacteria confirmed the activity of nZnO to prevent bacterial growth. Coatings composition and morphology were analyzed by thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. Moreover, the corrosion resistance was analyzed by evaluation of the polarization curves in DMEM at 37°C, and it was found that coatings containing nZnO increased the corrosion resistance compared to the bare substrate. Considering all results, the newly developed coatings represent a suitable alternative for the surface modification of metallic implants.