Alginate–lavender nanofibers with antibacterial and anti-inflammatory activity to effectively promote burn healing

One of the current challenges in wound care is the development of multifunctional dressings that can both protect the wound from external agents and promote the regeneration of the new tissue. Here, we show the combined use of two naturally derived compounds, sodium alginate and lavender essential oil, for the production of bioactive nanofibrous dressings by electrospinning, and their efficacy for the treatment of skin burns induced by midrange ultraviolet radiation (UVB). We demonstrate that the engineered dressings reduce the risk of microbial infection of the burn, since they stop the growth of Staphylococcus aureus. Furthermore, they are able to control and reduce the inflammatory response that is induced in human foreskin fibroblasts by lipopolysaccharides, and in rodents by UVB exposure. In particular, we report a remarkable reduction of pro-inflammatory cytokines when fibroblasts or animals are treated with the alginate-based nanofibers. The down-regulation of cytokines production and the absence of erythema on the skin of the treated animals confirm that the here described dressings are promising as advanced biomedical devices for burn management

Absolute and Direct MicroRNA Quantification Using DNA–Gold Nanoparticle Probes

DNA–gold nanoparticle probes are implemented in a simple strategy for direct microRNA (miRNA) quantification. Fluorescently labeled DNA-probe strands are immobilized on PEGylated gold nanoparticles (AuNPs). In the presence of target miRNA, DNA–RNA heteroduplexes are formed and become substrate for the endonuclease DSN (duplex-specific nuclease). Enzymatic hydrolysis of the DNA strands yields a fluorescence signal due to diffusion of the fluorophores away from the gold surface. We show that the molecular design of our DNA–AuNP probes, with the DNA strands immobilized on top of the PEG-based passivation layer, results in nearly unaltered enzymatic activity toward immobilized heteroduplexes compared to substrates free in solution. The assay, developed in a real-time format, allows absolute quantification of as little as 0.2 fmol of miR-203. We also show the application of the assay for direct quantification of cancer-related miR-203 and miR-21 in samples of extracted total RNA from cell cultures. The possibility of direct and absolute quantification may significantly advance the use of microRNAs as biomarkers in the clinical praxis

Lifespan curves of <i>Drosophila</i> flies nurtured with AuNPs treated food (5, 15, 40, and 80 nm) compared to two populations bred with normal food (CTRL) or supernatant treated food (SN).

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0029980#pone-0029980-g001" target="_blank">Fig. 1</a>, top and bottom, are relative to TES and TNN approach, respectively. Experimental points represent the average from 5 independent experiments (the standard deviations are reported as the curve symbols size). The lifespan curves of both TES and TNN experiments were validated by the non-parametric log-rank (Mantel-Cox) test (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0029980#pone.0029980.s006" target="_blank">Table S3</a>).</p

Male (left) and female (right) fertility tests relative to TES (top) and TNN experiments (bottom).

<p>Experimental points represent the average from 10 independent experiments and the error bars indicate the standard deviation (ns  =  non significant, i.e. p-value >0.05; **p-value <0.01; ***p-value <0.001).</p

Representative confocal microscopy images of Drosophila midgut in flies obtained from TES treatment.

<p>Nuclei are stained with Hoechst 33342 (blue) while cells containing DNA strand nicks are detected by TUNEL assay and fluoresce red (highlighted by the white arrows).</p

mRNA expression level analyzed by RT-qPCR of <i>Drosophila</i> treated with TES (top) and TNN (bottom) approaches.

<p>All data relative to RT-qPCR experiments were analyzed by statistical software to evaluate the significant difference with respect to the control (ns  =  non significant, i.e. p-value >0.05; *p-value <0.05; **p-value <0.01 ***p-value <0.001).</p

ROS measurements by DCF assay on TES and TNN treatments (top and bottom, respectively).

<p>Data are reported as relative fluorescence intensity normalized to the control (ns  =  non significant, i.e. p-value >0.05; ***p-value <0.001). Error bars  =  SD.</p

Fibrous wound dressings encapsulating essential oils as natural antimicrobial agents

Preventing infections is one of the main focuses of wound care. The colonisation of wounds by microorganisms can in fact have negative consequences on the healing process, delaying it. Here, we propose the use of essential oils as natural antimicrobial agents for cellulose-based fibrous dressings. We demonstrate the production of composite electrospun fibres that effectively encapsulate three different types of essential oils (cinnamon, lemongrass and peppermint). The fibrous scaffolds are able to inhibit the growth of Escherichia coli, even when small amounts of essential oils were used. At the same time, they are not cytotoxic, as proved by biocompatibility assays on skin cell models. The created dressings are promising as advanced biomedical devices for topical treatments

Toxicity Assessment of Silica Coated Iron Oxide Nanoparticles and Biocompatibility Improvement by Surface Engineering

<div><p>We have studied <i>in vitro</i> toxicity of iron oxide nanoparticles (NPs) coated with a thin silica shell (Fe₃O₄/SiO₂ NPs) on A549 and HeLa cells. We compared bare and surface passivated Fe₃O₄/SiO₂ NPs to evaluate the effects of the coating on the particle stability and toxicity. NPs cytotoxicity was investigated by cell viability, membrane integrity, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) assays, and their genotoxicity by comet assay. Our results show that NPs surface passivation reduces the oxidative stress and alteration of iron homeostasis and, consequently, the overall toxicity, despite bare and passivated NPs show similar cell internalization efficiency. We found that the higher toxicity of bare NPs is due to their stronger <i>in-situ</i> degradation, with larger intracellular release of iron ions, as compared to surface passivated NPs. Our results indicate that surface engineering of Fe₃O₄/SiO₂ NPs plays a key role in improving particles stability in biological environments reducing both cytotoxic and genotoxic effects.</p></div