Short-wave and near infrared π-conjugated polymers hosted in a biocompatible microemulsion: a pioneering approach for photoacoustic contrast agents.

In the present study a biocompatible oil-in-water (O/W) microemulsion was developed carrying short-wave infrared (SWIR) π-conjugated polymers and possessing photoacoustic properties for the first time. SWIR and NIR absorbing conjugated polymers were accomplished to be dissolved in a Food & Drug Administration (FDA) approved natural oil limonene, to formulate an O/W microemulsion using biocompatible surfactants (Span80, Labrasol®). Detailed structural characterization in the absence and presence of the polymers was performed by means of dynamic light scattering (DLS), small-angle X-ray scattering (SAXS) and electron paramagnetic resonance (EPR) spectroscopy. In terms of biological evaluation of the loaded microemulsions, inhibition of cell proliferation in various cancer cell lines without exhibiting significant cytotoxicity was tested through the MTT assay. The developed π-conjugated polymers hosted in O/W microemulsions represent a technological approach with a wide range of biomedical and bioelectronic applications and in this contribution, their photoacoustic properties are presented as a proof-of-concept.

Biological Evaluation of Oil-in-Water Microemulsions as Carriers of Benzothiophene Analogues for Dermal Applications.

During the last decade, many studies have been reported on the design and formulation of novel drug delivery systems proposed for dermal or transdermal administration. The efforts focus on the development of biocompatible nanodispersions that can be delivered to the skin and treat severe skin disorders, including cancer. In this context, oil-in-water (O/W) microemulsions have been developed to encapsulate and deliver lipophilic bioactive molecules for dermal application. An O/W biocompatible microemulsion composed of PBS buffer, Tween 80, and triacetin was assessed for its efficacy as a drug carrier of DPS-2, a lead compound, initially designed in-house to inhibit BRAFV600E oncogenic kinase. The system was evaluated through both in vitro and ex vivo approaches. The cytotoxic effect, in the presence and absence of DPS-2, was examined through the thiazolyl blue tetrazolium bromide (MTT) cell proliferation assay using various cell lines. Further investigation through Western blotting revealed that cells died of necrosis. Porcine ear skin was used as a skin model to evaluate the degree of permeation of DPS-2 through skin and assess its retention. Through the ex vivo experiments, it was clarified that encapsulated DPS-2 was distributed within the full thickness of the stratum corneum (SC) and had a high affinity to hair follicles.

Physicochemical Characteristics of Four Limonene-Based Nanoemulsions and Their Larvicidal Properties against Two Mosquito Species, Aedes albopictus and Culex pipiens molestus.

Negative impacts on the environment from the continuous use of synthetic insecticides against mosquitoes has driven research towards more ecofriendly products. Phytochemicals, classified as low-risk substances, have been recognized as potential larvicides of mosquitoes; however, problems related to water solubility and stability are limiting factors for their use in mosquito control programs in the field. In this context, many researchers have focused on formulating essential oils in nanoemulsions, exploiting innovative nanotechnology. In the current study, we prepared 4 (R)-(+)-limonene oil-in-water nanoemulsions using low and high energy methods, and we evaluated their physicochemical characteristics (e.g., viscosity, stability, mean droplet diameter, polydispersity index) and their bioactivity against larvae of two mosquito species of great medical importance, namely, Cx. pipiens molestus and Ae. albopictus. According to the dose-response bioassays with the limonene-based nanoemulsions and pure limonene (dissolved in organic solvent), the tested nanoformulations improved the activity of limonene against Ae. albopictus larvae, while the performance of limonene was either the same or better than limonene against Cx. pipiens molestus, depending on the applied system. Overall, we achieved the production of limonene-based delivery nanosystems, with sufficient lethal properties against mosquito larvae to consider them promising larvicidal formulations applicable to mosquito breeding sites.

Oil-In-Water Microemulsions as Hosts for Benzothiophene-Based Cytotoxic Compounds: An Effective Combination.

Targeted delivery of chemotherapeutics in order to overcome side effects and enhance chemosensitivity remains a major issue in cancer research. In this context, biocompatible oil-in-water (O/W) microemulsions were developed as matrices for the encapsulation of DPS-2 a benzothiophene analogue, exhibiting high cytotoxicity in various cancer cell lines, among them the MW 164 skin melanoma and Caco-2 human epithelial colorectal adenocarcinoma cell lines. The microemulsion delivery system was structurally characterized by dynamic light scattering (DLS) and electron paramagnetic resonance (EPR) spectroscopy. The effective release of a lipophilic encapsulated compound was evaluated via confocal microscopy. The cytotoxic effect, in the presence and absence of DPS-2, was examined through the thiazolyl blue tetrazolium bromide (MTT) cell proliferation assay. When encapsulated, DPS-2 was as cytotoxic as when dissolved in dimethyl sulfoxide (DMSO). Hence, the oil cores of O/W microemulsions were proven effective biocompatible carriers of lipophilic bioactive molecules in biological assessment experiments. Further investigation through fluorescence-activated cell sorting (FACS) analysis, comet assay, and Western blotting, revealed that DPS-2, although non-genotoxic, induced S phase delay accompanied by cdc25A degradation and a nonapoptotic cell death in both cell lines, which implies that this benzothiophene analogue is a deoxyribonucleic acid (DNA) replication inhibitor.

Encapsulation of carotenoids extracted from halophilic Archaea in oil-in-water (O/W) micro- and nano-emulsions.

Carotenoids extracted from halophilc Archaea have potential health benefits. Their poor water-solubility and low bioavailability is a challenge to their incorporation into foods. The aim of this work was the carotenoids encapsulation into two oil-in-water (O/W) dispersions, to increase their use as functional food applications. A nanoemulsion produced by high pressure homogenization and a spontaneously formed microemulsion were conceived. The limonene was the dispersed oil phase, and mixtures of Triton X-100/Tween-80 (3:1) as emulsifiers and of water/glycerol (2:1) as the continuous aqueous phase. The microemulsion monophasic area was determined through the pseudo-ternary phase diagram. Dynamic Light Scattering was used for the structural characterization of the nano- and micro-emulsions in the presence of the carotenoids. Moreover, the radical scavenging activity of the encapsulated carotenoids was examined by Electron Paramagnetic Resonance spectroscopy. The results confirmed the delivery systems design effectiveness to encapsulate and stabilize the carotenoids for food applications.

Effect of oleic acid on the properties of protein adsorbed layers at water/oil interfaces: An EPR study combined with dynamic interfacial tension measurements.

Multiphase food systems consist of complex interfacial layers where surface active molecules complete compete for adsorption and interact with one another affecting the interfacial properties and the behavior of the food systems involved. The present work focuses on the examination of interactions between proteins playing an which play an important role in milk-rich food systems (namely κ-casein and ß-lactoglobulin) and oleic acid (an anionic surfactant abundant in food systems) at the oil/water interface. An interesting feature of this system is that the molecules interacting at the interface originate from different phases and do not transfer/dissolve significantly to the other phase. The systems were examined using Electron Paramagnetic Resonance (EPR) spectroscopy and Dynamic Interfacial Tension measurements (dynamic interfacial tension and dynamic interfacial dilatational rheology). This combination of experimental methods provided the dynamics of adsorption at the interface and the mechanical properties of the interface allowing valuable insight on the interactions of the different molecules. The above information was coupled with direct information on fatty acid mobility in the oil bulk phase and indirect information on the degree of relative fatty acid/protein adsorption at the interface by EPR. Overall a synergistic effect of the protein and fatty acid on decreasing interfacial tension of the oil/water interface was evidenced. The fatty acid interacted differently with the random coil κ-casein and globular ß-lactoglobulin in terms of relative adsorption and in terms on its effect on mechanical properties. Thermal denaturation of ß-lactoglobulin affected the protein's interaction with the fatty acid due to conformational changes and exposure of non-polar sites.

Drug nanocarriers for cancer chemotherapy based on microemulsions: The case of Vemurafenib analog PLX4720.

Oil-in-water (O/W) microemulsions based on Tween 80 as the emulsifier and triacetin as the dispersed oil phase were formulated to be used as delivery vehicles of Vemurafenib analog PLX4720. PLX4720 is a lipophilic antitumor drug against various cancer types correlated with the BRAFV600E mutation. The limits of the single-phase region corresponding to O/W microemulsions as described by ternary phase diagrams were examined. Droplet size measurements determined by dynamic light scattering (DLS) showed mean droplet diameters equal to 10±0.1nm both in the presence and in absence of the drug. Cryogenic-transmission electron microscopy (Cryo-TEM) images of the microemulsions showed the existence of small structures with uniform size distribution having also average diameters of approximately 10nm. Electron paramagnetic resonance (EPR) spectroscopy applying the spin probing technique confirmed PLX4720 location in the oil cores excluding its participation in the surfactants monolayer. Furthermore, cell viability assays on colon cancer cell lines Colo-205 and HT29 showed that microemulsions did not exhibit any cytotoxicity when added in ratios between 0.005% v/v and 0.2% v/v. When the cells were treated with encapsulated PLX4720 at two different concentrations (0.063 and 0.12µΜ) the same response as when dissolved in classic DMSO was observed.

Candida albicans chronic colonisation in cystic fibrosis may be associated with inhaled antibiotics.

Candida albicans is increasingly recognised as a coloniser of the respiratory tract in cystic fibrosis (CF) patients. Yet, the potential role, if any, of the micro-organism in the progress of the disease remains unclear. In this study, we investigated the association between inhaled antibiotics and C. albicans chronic colonisation in patients with CF. A cohort of 121 CF patients born from 1988 to 1996 was, respectively, studied. The medical records of each patient were reviewed from the first time they attended the CF Centre until the occurrence of C. albicans chronic colonisation or their last visit for the year 2010. Chronic colonisation was defined as the presence of C. albicans in more than 50% of cultures in a given year. A number of possible confounders were included in the multivariate logistic regression analysis to identify an independent association between inhaled antibiotics and C. albicans chronic colonisation. Fifty-four (44.6%) of the 121 patients enrolled in the study developed chronic colonisation by the micro-organism. Multivariate logistic regression analysis determined the independent effect of inhaled antibiotic treatment on the odds of chronic colonisation (OR 1.112, 95% CI [1.007-1.229], P = 0.036). Candida albicans chronic colonisation may be associated with the duration of inhaled antibiotic treatment.

A novel homothallic variety of Agaricus bisporus comprises rare tetrasporic isolates from Europe.

Among 400 wild specimens of A. bisporus collected in Europe, only three were tetrasporic. In the case of two of them from France, a previous study showed that one was homokaryotic and hypothetically belonged to a homothallic entity while the other was heterokaryotic and possibly resulted from hybridization between a member of this entity and a classical bisporic strain. A third tetrasporic specimen recently was discovered in Greece. Morphological and genetic comparisons, using alloenzymatic markers, molecular markers and ITS polymorphisms, reveal that this third specimen is homokaryotic and belongs, with the homokaryotic specimen from France, to the same entity. Dissimilarity analysis confirms the hybrid origin of the heterokaryotic specimen. Varietal status is proposed for this homothallic, highly homogeneous entity, and A. bisporus var. eurotetrasporus is described. This novel variety clearly differs from var. bisporus by its tetrasporic basidia and from var. burnettii by its longer spores. It has a complex story because it can interbreed with var. bisporus and shares the same habitat; however, because of its homothallic life cycle and its partial intersterility, it is probably in the process of speciation.