Subcuticular microstructure of the hornet's gaster: Its possible function in thermoregulation

New Solutions of Fractional Jeffrey Fluid with Ternary Nanoparticles Approach

The existing work deals with the Jeffrey fluid having an unsteady flow, which is moving along a vertical plate. A fractional model with ternary, hybrid, and nanoparticles is obtained. Using suitable dimensionless parameters, the equations for energy, momentum, and Fourier's law were converted into non-dimensional equations. In order to obtain a fractional model, a fractional operator known as the Prabhakar operator is used. To find a generalized solution for temperature as well as a velocity field, the Laplace transform is used. With the help of graphs, the impact of various parameters on velocity as well as temperature distribution is obtained. As a result, it is noted that ternary nanoparticles approach can be used to increase the temperature than the results obtained in the recent existing literature. The obtained solutions are also useful in the sense of choosing base fluids (water, kerosene and engine oil) for nanoparticles to achieved the desired results. Further, by finding the specific value of fractional parameters, the thermal and boundary layers can be controlled for different times. Such a fractional approach is very helpful in handling the experimental data by using theoretical information. Moreover, the rate of heat transfer for ternary nanoparticles is greater in comparison to hybrid and mono nanoparticles. For large values of fractional parameters, the rate of heat transfer decreases while skin friction increases. Finally, the present results are the improvement of the results that have already been published recently in the existing literature. Fractional calculus enables us to control the boundary layers as well as rate of heat transfer and skin friction for finding suitable values of fractional parameters. This approach can be very helpful in electronic devices and industrial heat management system.

Optimization of the incubation parameters for biogenic synthesis of WO3 nanoparticles using Taguchi method

Green synthesis of metal nanoparticles is gathering attention due to eco-friendly processing. Tungsten oxide (WO₃) nanoparticles have immense applications as semiconductors, antimicrobials and photo thermal materials but their synthesis using biological systems is hitherto unpublicized. The paper discusses synthesis of WO₃ nanoparticles using Stenotrophomonas maltophilia and the optimization of physico-chemical parameters of incubation which influence the growth and metabolism of the bacterium and consequently the size of the WO₃ nanoparticles. The biogenic synthesis of WO₃ nanoparticles was confirmed by ATR-FTIR and X-ray diffraction analysis. Taguchi and analysis of variance method was applied to optimize the physico-chemical parameters (pH, temperature, time, aeration rate and concentration), considering particle size and poly dispersity index (PDI) of the nanoparticles as the experimental responses. Under the design of experiments technique, Taguchi's L27 array was selected to determine the optimal process parameters which could significantly reduce the particle size and PDI of WO₃ nanoparticles. Statistical analysis by signal-to-noise ratio, regression analysis and ANOVA (95% confidence level) on experimental responses confirmed pH and aeration as most influential while temperature and time as least influential parameters. pH 8, Temperature 40 °C, aeration 200 RPM, time 3 days and concentration of sodium tungstate at 1 mM (p3t3r3d3c1) was the most effective level and parameters combination for smallest particle size and PDI of WO₃ nanoparticles. Regression models developed for particle size and PDI exhibited a linear regression of 97.80% and 90.89% respectively, while the confirmation test validated the size and PDI of the experimental values against predicted results. SEM image of WO₃ nanoparticles illustrated the same particle size as that predicted, further validating the model. The study can be applied to optimize any process parameters in the industry or on biological systems.

Application of MXene in the diagnosis and treatment of breast cancer: A critical overview

Breast cancer is the second most common cancer worldwide. Prognosis and timely treatment can reduce the illness or improve it. The use of nanomaterials leads to timely diagnosis and effective treatment. MXenes are a 2D material with a unique composition of attributes, containing significant electrical conductance, high optical characteristics, mechanical consistency, and excellent optical properties. Current advances and insights show that MXene is far more promising in biotechnology applications than current nanobiotechnology systems. MXenes have various applications in biotechnology and biomedicine, such as drug delivery/loading, biosensor, cancer treatment, and bioimaging programs due to their high surface area, excellent biocompatibility, and physicochemical properties. Surface modifications MXenes are not only biocompatible but also have multifunctional properties, such as aiming ligands for preferential agglomeration at the tumor sites for photothermal treatment. Studies have shown that these nanostructures, detection, and breast cancer therapy are more acceptable than present nanosystems in in vivo and in vitro. This review article aims to investigate the structure of MXene, its various synthesis methods, its application to cancer diagnosis, cytotoxicity, biodegradability, and cancer treatment by the photothermal process (in-vivo and in-vitro).

A cationic lipid mediated CRISPR/Cas9 technique for the production of stable genome edited citrus plants

BACKGROUND

The genetic engineering of crops has enhanced productivity in the face of climate change and a growing global population by conferring desirable genetic traits, including the enhancement of biotic and abiotic stress tolerance, to improve agriculture. The clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) system has been found to be a promising technology for genomic editing. Protoplasts are often utilized for the development of genetically modified plants through in vitro integration of a recombinant DNA fragment into the plant genome. We targeted the citrus Nonexpressor of Pathogenesis-Related 3 (CsNPR3) gene, a negative regulator of systemic acquired resistance (SAR) that governs the proteasome-mediated degradation of NPR1 and developed a genome editing technique targeting citrus protoplast DNA to produce stable genome-edited citrus plants.

RESULTS

Here, we determined the best cationic lipid nanoparticles to deliver donor DNA and described a protocol using Lipofectamine™ LTX Reagent with PLUS Reagent to mediate DNA delivery into citrus protoplasts. A Cas9 construct containing a gRNA targeting the CsNPR3 gene was transfected into citrus protoplasts using the cationic lipid transfection agent Lipofectamine with or without polyethylene glycol (PEG, MW 6000). The optimal transfection efficiency for the encapsulation was 30% in Lipofectamine, 51% in Lipofectamine with PEG, and 2% with PEG only. Additionally, plasmid encapsulation in Lipofectamine resulted in the highest cell viability percentage (45%) compared with PEG. Nine edited plants were obtained and identified based on the T7EI assay and Sanger sequencing. The developed edited lines exhibited downregulation of CsNPR3 expression and upregulation of CsPR1.

CONCLUSIONS

Our results demonstrate that utilization of the cationic lipid-based transfection agent Lipofectamine is a viable option for the successful delivery of donor DNA and subsequent successful genome editing in citrus.

Microfluidic platforms for single neuron analysis

Single-neuron actions are the basis of brain function, as clinical sequelae, neuronal dysfunction or failure for most of the central nervous system (CNS) diseases and injuries can be identified via tracing single-neurons. The bulk analysis methods tend to miscue critical information by assessing the population-averaged outcomes. However, its primary requisite in neuroscience to analyze single-neurons and to understand dynamic interplay of neurons and their environment. Microfluidic systems enable precise control over nano-to femto-liter volumes via adjusting device geometry, surface characteristics, and flow-dynamics, thus facilitating a well-defined micro-environment with spatio-temporal control for single-neuron analysis. The microfluidic platform not only offers a comprehensive landscape to study brain cell diversity at the level of transcriptome, genome, and/or epigenome of individual cells but also has a substantial role in deciphering complex dynamics of brain development and brain-related disorders. In this review, we highlight recent advances of microfluidic devices for single-neuron analysis, i.e., single-neuron trapping, single-neuron dynamics, single-neuron proteomics, single-neuron transcriptomics, drug delivery at the single-neuron level, single axon guidance, and single-neuron differentiation. Moreover, we also emphasize limitations and future challenges of single-neuron analysis by focusing on key performances of throughput and multiparametric activity analysis on microfluidic platforms.

Recent Interventions for Nanotechnology Based Drug Products: Insights into the Regulatory Aspects

BACKGROUND

Nanotechnology has been one of the most prominent forefront grounds in several traditional research areas of science and technology, and development of medicines at nanoscale can be reflected by the tremendous surge in market interest. Present outlook: Its applications include various research areas of medicine, drug delivery technology, diagnostic devices, tissue engineering and gene therapy. Along with immense advances, this technology comes with major limitations including potential immune reactivity and complex characterization of these products. Regulatory challenges: The lack of a proper regulatory perspective due to infidelities in scientific findings have led to further uncertainties and vagueness of the nanoscale domain, particularly its safety implications. Guideline scenario: Early development pathways and regulations should be a top-notch priority to help researchers fail faster and more economically. This would facilitate the peaking utility of these materials in medicine without compromising public health and environmental integrity. This review attempts to emphasize the regulatory rationales of key considerations in nanotechnology along with a portray of the present scenario.

Protective effect of cerium oxide nanoparticle on sperm quality and oxidative damage in malathion-induced testicular toxicity in rats: An experimental study

BACKGROUND

Malathion is an organophosphorus pesticide that commonly used in many agricultural and non-agricultural processes. Previous studies have reported the effects of melatonin on the reproductive system. Cerium dioxide nanoparticles (CeNPs) due to their antioxidative properties are promising to impact on the development of male infertility.

OBJECTIVE

The aim of this study was to evaluate the effect of CeNPs on oxidative stress and sperm parameters after malathion exposure of male rats.

MATERIALS AND METHODS

36 adult male Wistar rats were divided into 6 groups (n=6/each): Control, CeNPs -treated control (15 and 30 mg/kg/day), malathion (100 mg/ kg/day), and CeNPs -treated malathion groups (15 and 30 mg/ kg/day). At the end of the study (4 wk), the sperm counts, motility, and viability in the testis of rats were measured, also lipid peroxidation, total antioxidant capacity, and total thiol groups in homogenate testis were investigated.

RESULTS

Malathion significantly reduced sperm count, viability, and motility than the control rats (p<0.001). Co-treatment of malathion with CeNPs 30 mg/kg had a protective effect on sperm counts (p=0.03), motility (p=0.01), and viability (p<0.001) compare to malathion group. Also, the results showed that malathion reduced testis total anti-oxidant capacity, the total thiol group, and increased testis malondialdehyde than the control rats (p<0.001). CeNPs 30 mg/kg are increased total antioxidant capacity (p<0.001) and total thiol group (p=0.03) compared to malathion group. CeNPs at both doses (15 and 30 mg/kg) improved malondialdehyde than the malathion group (p<0.001 and p=0.01 respectively).

CONCLUSION

CeNPs 30 mg/kg administered considerably restored testicular changes induced by malathion. The improvement of oxidative stress by CeNPs may be associated with increased sperm counts, motility and viability in the testis.

Metallic Nano-Composite Toxicity Evaluation by Zebrafish Embryo Toxicity Test with Identification of Specific Exposure Biomarkers

Nanomaterials (NM) have different shapes and can be composed of different materials such as carbon, silicon, and some metals like gold, silver, and titanium. They are used as fillers, catalysts, semiconductors, cosmetics, drug carriers in medicine, energy storage systems, and antifriction coatings. NM are the parent compounds of nanoparticles (NPs), which may be divided into two groups: fullerenes and engineered nanoparticles (ENPs). After crossing the cell membrane, NPs may be stored in vesicles, mitochondria, and additional organelles within epithelial cells. They may generate reactive oxygen species, oxidative stress, and cytotoxicity, as well as denaturation of proteins, apoptosis, and necrosis. Nowadays, new toxicological data are required to assess the potential exposure of the environment and human beings to pollutants. The aim of the present investigation is to evaluate the toxicity of the metallic nano-composite by the zebrafish embryo toxicity test (ZFET). The methods described here can be easily adapted to other nanocomposites or nanomaterials with some variations. © 2017 by John Wiley & Sons, Inc.

Impact of copper oxide nanomaterials on differentiated and undifferentiated Caco-2 intestinal epithelial cells; assessment of cytotoxicity, barrier integrity, cytokine production and nanomaterial penetration

BACKGROUND

Copper oxide nanomaterials (CuO NMs) are exploited in a diverse array of products including antimicrobials, inks, cosmetics, textiles and food contact materials. There is therefore a need to assess the toxicity of CuO NMs to the gastrointestinal (GI) tract since exposure could occur via direct oral ingestion, mucocillary clearance (following inhalation) or hand to mouth contact.

METHODS

Undifferentiated Caco-2 intestinal cells were exposed to CuO NMs (10 nm) at concentrations ranging from 0.37 to 78.13 μg/cm2 Cu (equivalent to 1.95 to 250 μg/ml) and cell viability assessed 24 h post exposure using the alamar blue assay. The benchmark dose (BMD 20), determined using PROAST software, was identified as 4.44 μg/cm2 for CuO NMs, and 4.25 μg/cm2 for copper sulphate (CuSO4), which informed the selection of concentrations for further studies. The differentiation status of cells and the impact of CuO NMs and CuSO4 on the integrity of the differentiated Caco-2 cell monolayer were assessed by measurement of trans-epithelial electrical resistance (TEER), staining for Zonula occludens-1 (ZO-1) and imaging of cell morphology using scanning electron microscopy (SEM). The impact of CuO NMs and CuSO4 on the viability of differentiated cells was performed via assessment of cell number (DAPI staining), and visualisation of cell morphology (light microscopy). Interleukin-8 (IL-8) production by undifferentiated and differentiated Caco-2 cells following exposure to CuO NMs and CuSO4 was determined using an ELISA. The copper concentration in the cell lysate, apical and basolateral compartments were measured with Inductive Coupled Plasma Optical Emission Spectrometry (ICP-OES) and used to calculate the apparent permeability coefficient (Papp); a measure of barrier permeability to CuO NMs. For all experiments, CuSO4 was used as an ionic control.

RESULTS

CuO NMs and CuSO4 caused a concentration dependent decrease in cell viability in undifferentiated cells. CuO NMs and CuSO4 translocated across the differentiated Caco-2 cell monolayer. CuO NM mediated IL-8 production was over 2-fold higher in undifferentiated cells. A reduction in cell viability in differentiated cells was not responsible for the lower level of cytokine production observed. Both CuO NMs and CuSO4 decreased TEER values to a similar extent, and caused tight junction dysfunction (ZO-1 staining), suggesting that barrier integrity was disrupted.

CONCLUSIONS

CuO NMs and CuSO4 stimulated IL-8 production by Caco-2 cells, decreased barrier integrity and thereby increased the Papp and translocation of Cu. There was no significant enhancement in potency of the CuO NMs compared to CuSO4. Differentiated Caco-2 cells were identified as a powerful model to assess the impacts of ingested NMs on the GI tract.

Graphene- gold based nanocomposites applications in cancer diseases; Efficient detection and therapeutic tools

Early detection and efficient treatment of cancer disease remains a drastic challenge in 21st century. Throughout the bulk of funds, studies, and current therapeutics, cancer seems to aggressively advance with drug resistance strains and recurrence rates. Nevertheless, nanotechnologies have indeed given hope to be the next generation for oncology applications. According to US National cancer institute, it is anticipated to revolutionize the perspectives of cancer diagnosis and therapy. With such success, nano-hybrid strategy creates a marvelous preference. Herein, graphene-gold based composites are being increasingly studied in the field of oncology, for their outstanding performance as robust vehicle of therapeutic agents, built-in optical diagnostic features, and functionality as theranostic system. Additional modes of treatments are also applicable including photothermal, photodynamic, as well as combined therapy. This review aims to demonstrate the various cancer-related applications of graphene-gold based hybrids in terms of detection and therapy, highlighting the major attributes that led to designate such system as a promising ally in the war against cancer.

Exoskeleton may influence the internal body temperatures of Neotropical dung beetles (Col. Scarabaeinae)

The insect exoskeleton is a multifunctional coat with a continuum of mechanical and structural properties constituting the barrier between electromagnetic waves and the internal body parts. This paper examines the ability of beetle exoskeleton to regulate internal body temperature considering its thermal permeability or isolation to simulated solar irradiance and infrared radiation. Seven Neotropical species of dung beetles (Coleoptera, Scarabaeinae) differing in colour, surface sculptures, size, sexual dimorphism, period of activity, guild category and altitudinal distribution were studied. Specimens were repeatedly subjected to heating trials under simulated solar irradiance and infrared radiation using a halogen neodymium bulb light with a balanced daylight spectrum and a ceramic infrared heat emitter. The volume of exoskeleton and its weight per volume unit were significantly more important for the heating rate at the beginning of the heating process than for the asymptotic maximum temperature reached at the end of the trials: larger beetles with relatively thicker exoskeletons heated more slowly. The source of radiation greatly influences the asymptotic temperature reached, but has a negligible effect in determining the rate of heat gain by beetles: they reached higher temperatures under artificial sunlight than under infrared radiation. Interspecific differences were negligible in the heating rate but had a large magnitude effect on the asymptotic temperature, only detectable under simulated sun irradiance. The fact that sun irradiance is differentially absorbed dorsally and transformed into heat among species opens the possibility that differences in dorsal exoskeleton would facilitate the heat gain under restrictive environmental temperatures below the preferred ones. The findings provided by this study support the important role played by the exoskeleton in the heating process of beetles, a cuticle able to act passively in the thermal control of body temperature without implying energetic costs and metabolic changes.

Analysis of metallic and metal oxide nanomaterial environmental emissions

The current study presents evidence on metallic and metal oxide engineered nanomaterial (ENM) emissions into the environment and an analytic perspective of the outcomes of evaluated studies with respect to different individual end points along the lifecycle trajectory. The key findings suggest that 1) the published literature on emissions of metallic ENMs is limited in both the number and information available on the characteristics of emitted ENMs; 2) the studies are classified as experimental and computational studies focused on predicting ENM emissions; 3) the majority of studies investigated ENM emissions during nanomaterial use and waste management, followed by raw material manufacturing, and finally, nano-enabled product manufacturing; 4) the studies primarily reported the concentration/quantity of emitted ENMs, whereas the physical-chemical characteristics of emitted ENMs were rarely measured or reported; and 5) the published literature primarily focused on emissions of silver and titanium dioxide ENMs and lacked similar information on other surging metallic and metal oxide ENMs such as nano-zero valent iron (nZVI), aluminum (Al), and aluminum oxide (Al2O3) ENMs. The evidence suggests that emitted nanoparticles into the air cover a wide range of concentrations below and above the allowable occupational exposure limits. The concentrations of nanoparticles in water systems are considered in the toxic to very toxic range for a variety of biological species. Given the critical gaps in knowledge, one cannot read across different sources of emissions for metallic and metal oxide ENMs hampering efforts with respect to understanding realistic scenarios for transformations in the natural environment and biological media.

Benchmark study on fine-mode aerosol in a big urban area and relevant doses deposited in the human respiratory tract

It is well-known that the health effects of PM increase as particle size decreases: particularly, great concern has risen on the role of UltraFine Particles (UFPs). Starting from the knowledge that the main fraction of atmospheric aerosol in Rome is characterized by significant levels of PM2.5 (almost 75% of PM10 fraction is PM2.5), the paper is focused on submicron particles in such great urban area. The daytime/nighttime, work-/weekdays and cold/hot seasonal trends of submicron particles will be investigated and discussed along with NOx and total PAH drifts demonstrating the primary origin of UFPs from combustion processes. Furthermore, moving from these data, the total dose of submicron particles deposited in the respiratory system (i.e., head, tracheobronchial and alveolar regions in different lung lobes) has been estimated. Dosimeter estimates were performed with the Multiple-Path Particle Dosimetry model (MPPD v.2.1). The paper discusses the aerosol doses deposited in the respiratory system of individuals exposed in proximity of traffic. During traffic peak hours, about 6.6 × 10(10) particles are deposited into the respiratory system. Such dose is almost entirely made of UFPs. According to the greater dose estimated, right lung lobes are expected to be more susceptible to respiratory pathologies than left lobes.

Small gold nanocomposites obtained in reverse micelles as nanoreactors. Effect of surfactant, optical properties and activity against Pseudomonas aeruginosa

High antibacterial convergence of an antimicrobial synthetic peptide and small gold nanoparticles against Pseudomonas aeruginosa.

The impact of the polar core size and external organic media composition on micelle–micelle interactions: the effect on gold nanoparticle synthesis

An easy way to modulate reverse micelles as nanoreactors to produce different kinds of gold nanoparticles.

Effects of N-acetyl-L-cysteine on target sites of hydroxylated fullerene-induced cytotoxicity in isolated rat hepatocytes

The effects of N-acetyl-L-cysteine (NAC) on cytotoxicity caused by a hydroxylated fullerene [C60(OH)24], which is known a nanomaterial and/or a water-soluble fullerene derivative, were studied in freshly isolated rat hepatocytes. The exposure of hepatocytes to C60(OH)24 at a concentration of 0.1 mM caused time (0-3 h)-dependent cell death accompanied by the formation of cell blebs, loss of cellular ATP, and reduced glutathione (GSH) and protein thiol levels, as well as the accumulation of glutathione disulfide and malondialdehyde (MDA), indicating lipid peroxidation. Despite this, C60(OH)24-induced cytotoxicity was effectively prevented by NAC pretreatment ranging in concentrations from 1 to 5 mM. Further, the loss of mitochondrial membrane potential (MMP) and generation of oxygen radical species in hepatocytes incubated with C60(OH)24 were inhibited by pretreatment with NAC, which caused increases in cellular and/or mitochondrial levels of GSH, accompanied by increased levels of cysteine via enzymatic deacetylation of NAC. On the other hand, severe depletion of cellular GSH levels caused by diethyl maleate at a concentration of 1.25 mM led to the enhancement of C60(OH)24-induced cell death accompanied by a rapid loss of ATP. Taken collectively, these results indicate that pretreatment with NAC ameliorates (a) mitochondrial dysfunction linked to the depletion of ATP, MMP, and mitochondrial GSH level and (b) induction of oxidative stress assessed by reactive oxygen species generation, losses of intracellular GSH and protein thiol levels, and MDA formation caused by C60(OH)24, suggesting that the onset of toxic effects is at least partially attributable to a thiol redox-state imbalance as well as mitochondrial dysfunction related to oxidative phosphorylation.

Quantum dot applications endowing novelty to analytical proteomics

This review surveys all the state-of-art applications of quantum dots (QDs) in conventional and modern analytical methods in proteomic studies. A brief introduction of QDs and their properties is initially presented followed by outlining the application of QDs in fluorescence, MS, imaging, and cancer-based proteomics. The in-depth application of QDs in MALDI-MS and surface assisted laser desorption/ionization-MS has been elaborately discussed, summarizing the speculated mechanism behind the protein-QDs interactions during QD matrix applications leading to enhanced detection sensitivity.

Cytotoxic effects of hydroxylated fullerenes on isolated rat hepatocytes via mitochondrial dysfunction

The cytotoxic effects of hydroxylated fullerenes, also termed fullerenols or fullerols [C(60)(OH)( n )], which are known nanomaterials and water-soluble fullerene derivatives, were studied in freshly isolated rat hepatocytes. The exposure of hepatocytes to C(60)(OH)(24) caused not only concentration (0-0.25 mM)- and time (0-3 h)-dependent cell death accompanied by the formation of cell blebs, loss of cellular ATP, reduced glutathione (GSH), and protein thiol levels, but also the accumulation of glutathione disulfide and malondialdehyde, indicating lipid peroxidation. Of the other analogues examined, the cytotoxic effects of C(60)(OH)(12) and fullerene C(60) at a concentration of 0.125 mM were less than those of C(60)(OH)(24). The loss of mitochondrial membrane potential and generation of oxygen radical species in hepatocytes incubated with C(60)(OH)(24) were greater than those with C(60)(OH)(12) and fullerene C(60). In the oxygen consumption of mitochondria isolated from rat liver, the ratios of state-3/state-4 respiration were more markedly decreased by C(60)(OH)(24) and C(60)(OH)(12) compared with C(60). In addition, C(60)(OH)(24) and C(60)(OH)(12) resulted in the induction of the mitochondrial permeability transition (MPT), and the effects of C(60)(OH)(12) were less than those of C(60)(OH)(24). Taken collectively, these results indicate that (a) mitochondria are target organelles for fullerenols, which elicit cytotoxicity through mitochondrial failure related to the induction of the MPT, mitochondrial depolarization, and inhibition of ATP synthesis in the early stage and subsequently oxidation of GSH and protein thiols, and lipid peroxidation through oxidative stress at a later stage; and (b) the toxic effects of fullerenols may depend on the number of hydroxyl groups participating in fullerene in rat hepatocytes.

Iron Oxide Magnetic Nanotubes and Their Drug Loading and Release Capabilities

Iron oxide magnetic nanomaterials are among the most widely used nanomaterials in nanomedicine. Due to their magnetic and structural properties, iron oxide magnetic nanotubes are extremely attractive for biomedical applications. This paper presents the synthesis of iron oxide magnetic nanotubes, and their potential applications in drug delivery. Three types of iron oxide magnetic nanotubes, i.e., hematite, maghemite, and magnetite, were synthesized using template and hydrothermal methods, and the effects of synthesis methods on the morphological and crystalline properties of the synthesized magnetic nanotubes were analyzed. The magnetization properties of the three types of synthesized magnetic nanotubes and their responses to external magnetic fields were studied. To explore their applications in drug delivery, the drug loading and release capabilities of the synthesized magnetic nanotubes were investigated. The final part of this paper discusses several important issues related to the applications of iron oxide magnetic nanotubes for drug delivery, especially the controlled release of drugs.

Nanostructured Biomaterials with Controlled Properties Synthesis and Characterization

Magnetic nanoparticles were obtained using an adjusted Massart method and were covered in a layer-by-layer technique with hydrogel-type biocompatible shells, from chitosan and hyaluronic acid. The synthesized nanocomposites were characterized using dynamic light scattering, transmission electron microscopy, and Fourier transformed infrared spectroscopy. Biocompatibility of magnetic nanostructures was determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) cell proliferation assay, swelling tests, and degradation tests. In addition, interaction of hydrogel-magnetic nanoparticles with microorganisms was studied. The possibility of precise nanoparticles size control, as long as the availability of bio-compatible covering, makes them suitable for biomedical applications.

Cytotoxicity of titanium dioxide nanoparticles in mouse fibroblast cells

Nanotitanium dioxide (TiO2) is an important industrial material that is widely used as an additive in cosmetics, pharmaceuticals, and food colorants. Although the small size of the TiO2 nanoparticle is useful in various applications, the biosafety of this material needs to be evaluated. In this study, mouse fibroblast (L929) cells were used to evaluate the cytotoxicity of different concentrations (3-600 microg/mL) of homogeneous and weakly aggregated TiO2 nanoparticles in aqueous solution. The L929 cells became round and even shrank as the concentration of TiO2 nanoparticles increased. Moreover, TiO2 nanoparticle-treated cells had condensed fragmented chromatin or were directly necrosed, as observed by acridine orange (AO) staining. The transmission electron microscopy (TEM) analysis showed that in cells cultured in a medium containing 300 microg/mL TiO2, the number of lysosomes increased, and some cytoplasmic organelles were damaged. In addition, there was a significant increase in oxidative stress at higher TiO2 nanoparticle concentrations (>60 microg/mL). As the concentration of TiO2 nanoparticles increased in the culture medium, the levels of reactive oxygen species (ROS) and lactate dehydrogenase (LDH) increased, while those of methyl tetrazolium cytotoxicity (MTT), glutathione (GSH), and superoxide dismutase (SOD) decreased. A possible mechanism for the cytotoxicity of TiO2 nanoparticles is also discussed.

EcoR124I: from plasmid-encoded restriction-modification system to nanodevice

SUMMARY

Plasmid R124 was first described in 1972 as being a new member of incompatibility group IncFIV, yet early physical investigations of plasmid DNA showed that this type of classification was more complex than first imagined. Throughout the history of the study of this plasmid, there have been many unexpected observations. Therefore, in this review, we describe the history of our understanding of this plasmid and the type I restriction-modification (R-M) system that it encodes, which will allow an opportunity to correct errors, or misunderstandings, that have arisen in the literature. We also describe the characterization of the R-M enzyme EcoR124I and describe the unusual properties of both type I R-M enzymes and EcoR124I in particular. As we approached the 21st century, we began to see the potential of the EcoR124I R-M enzyme as a useful molecular motor, and this leads to a description of recent work that has shown that the R-M enzyme can be used as a nanoactuator. Therefore, this is a history that takes us from a plasmid isolated from (presumably) an infected source to the potential use of the plasmid-encoded R-M enzyme in bionanotechnology.

Ingested microscopic plastic translocates to the circulatory system of the mussel, Mytilus edulis (L)

Plastics debris is accumulating in the environment and is fragmenting into smaller pieces; as it does, the potential for ingestion by animals increases. The consequences of macroplastic debris for wildlife are well documented, however the impacts of microplastic (< 1 mm) are poorly understood. The mussel, Mytilus edulis, was used to investigate ingestion, translocation, and accumulation of this debris. Initial experiments showed that upon ingestion, microplastic accumulated in the gut. Mussels were subsequently exposed to treatments containing seawater and microplastic (3.0 or 9.6 microm). After transfer to clean conditions, microplastic was tracked in the hemolymph. Particles translocated from the gut to the circulatory system within 3 days and persisted for over 48 days. Abundance of microplastic was greatest after 12 days and declined thereafter. Smaller particles were more abundant than larger particles and our data indicate as plastic fragments into smaller particles, the potential for accumulation in the tissues of an organism increases. The short-term pulse exposure used here did not result in significant biological effects. However, plastics are exceedingly durable and so further work using a wider range of organisms, polymers, and periods of exposure will be required to establish the biological consequences of this debris.

Inhibition of Endotoxin-Induced Uveitis by Methylprednisolone Acetate Nanosuspension in Rabbits

PURPOSE

In this study, nanoformulations of methylprednisolone acetate (MPA) were formulated by using a copolymer of poly(ethylacrylate, methyl-methacrylate and chlorotrimethyl-ammonioethyl methacrylate) to study their impacts on the inhibition of inflammatory symptoms in rabbits with endotoxin-induced uveitis (EIU).

METHODS

A modified quasiemulsion solvent diffusion technique was used for the preparation of the nanoparticles. The drug-release profiles and physicochemical characteristics of the nanoformulations were studied by means of X-ray crystallography, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Particle-size analysis yielded mean diameters of approximately 380, 460, and 580 (nm) for copolymer nanoparticles at the ratios of 1:2.5, 1:5, and 1:10, respectively. Major clinical symptoms of EIU (e.g., morphologic changes, leukocytes numbers, and protein levels within the aqueous humor) were examined.

RESULTS

Upon the physicochemical characterizations, no crystal changes or chemical interactions were observed for the copolymer nanoparticles. The 1:2.5 ratio of drug polymer resulted in the most controlled release of MPA. The in vivo examinations revealed that the endotoxin-induced inflammation can be inhibited by the copolymer nanosuspension more significantly than by the microsuspension of MPA itself in the rabbits with EIU.

CONCLUSIONS

Based on our findings, we suggest that the copolymer nanosuspension may favor the localized, controlled ocular delivery of MPA for the prevention of inflammatory symptoms in ocular diseases.

Silica-immobilized enzymes for multi-step synthesis in microfluidic devices

The combinatorial synthesis of 2-aminophenoxazin-3-one (APO) in a microfluidic device is reported. Individual microfluidic chips containing metallic zinc, silica-immobilized hydroxylaminobenzene mutase and silica-immobilized soybean peroxidase are connected in series to create a chemo-enzymatic system for synthesis. Zinc catalyzes the initial reduction of nitrobenzene to hydroxylaminobenzene which undergoes a biocatalytic conversion to 2-aminophenol, followed by enzymatic polymerization to APO. Silica-immobilization of enzymes allows the rapid stabilization and integration of the biocatalyst within a microfluidic device with minimal preparation. The system proved suitable for synthesis of a complex natural product (APO) from a simple substrate (nitrobenzene) under continuous flow conditions.

Presence of a thermoregulatory hot spot in the prothorax of the large carpenter bee and the bumble bee

In both the large carpenter bee (Xylocopa pubescens) and the bumblebee (Bombus terrestris), a hot spot was detected in the center of the prothorax on its dorsal-external aspect. In both cases, the temperature in this hot spot was found to be greater than the ambient temperature and that at the tip of the gaster. In B. terrestris, it was higher by 9-10 degrees C from that at the gaster tip and by 15-16 degrees C from the ambient temperature, while in X. pubescens the corresponding differences were 11-20 degrees C and 18-19 degrees C, respectively. The recorded thermal differences were not fixed but were rather variable, temporally as well as individually, but invariably all individuals measured showed these temperature differences. Furthermore, in none of the studied specimens was a hot spot detected in any part of the body other than the prothorax. From this hot spot in the prothorax, there is a cascade of temperatures in both directions, that is, anteriorly towards the head and posteriorly towards the gaster, with a graded drop in temperature in either direction. This article discusses possible reasons for the existence of such a hot spot in this particular location (the prothorax), its role or function, and its mode of operation. The authors speculate that it is a thermoregulatory center (for heating or cooling) that might be present in possibly all Hymenoptera that spend a considerable part of their life flying, regardless of whether they are social, parasocial, or solitary.

Identifying the region influencing the cis-mode of maturation of West Nile (Sarafend) virus using chimeric infectious clones

West Nile (Sarafend) virus [WN(S)V] has been shown to egress by budding at the plasma membrane of infected cells. However, the region influencing this mode of virus release remains to be deciphered. In this study, we have constructed three chimeric clones in which specific regions of West Nile (Wengler) virus [WN(W)V] were replaced for the corresponding regions of WN(S)V in the full-length infectious clone of WN(S)V to define the region responsible for the cis-mode of WN(S)V maturation. The WN(W)V matures by the trans-mode. All of the resulting chimeric viruses were found to be infective. Transmission electron microscopy analyses performed in Vero cells infected with these chimeric viruses disclosed that the 5' end of the WN(S)V genome plays a major role in influencing the process of maturation at the plasma membrane.

A thermoregulatory center in hornets: IR photography

In the Oriental hornet Vespa orientalis (Hymenoptera, Vespinae), there is on the dorsal side of the thorax, beneath the mesoscutum plate of the prothorax and around the median notal suture, a lump that, in the course of hornet activity, is warmer by 9 degrees C from the surrounding milieu and by up to 6 degrees C from other body parts of the hornet. This lump is about 1 mm in diameter, butterfly-shaped, and its upper, posterior border abuts the base of the forewings. During hornet activity and via Infra Red photography one can observe heat extensions stemming from the center of the lump and proceeding forward in the direction of the head, downward toward the legs and backwards toward the bases of the wings. The warmest region is the center of the lump, with its margins showing a lower temperature. As for the legs of the hornet, their upper part is warmer than the other parts. The temperature gradients along the hornet's body are dependent on the extent and nature of hornet activity. Thus, during flight or ventilation activity, the thorax is the warmest part of the body, while the wings, legs, and antennae, as well as the posterior part of the gaster are colder, yet all these body parts are still warmer to varying degrees than the surrounding milieu. Thus, at night, when sentry worker hornets stand guard around the nest entrance and remain practically motionless, the temperature differences between the various body parts are retained unchanged. We conjecture that the described butterfly-shaped lump is a thermoregulatory center (TC), which is neurogenically activated, since the changes occurring in it are rapid, a matter of one to several seconds and do not appear to be directly dependent on the hemolymph supply. The thermoregulatory center keeps a high constant temperature apparently related to hornet activity and the environmental conditions. The temperature cascade is most probably regulated via the tracheal system. Apparently another system activated by a heat pump mechanism keeps the gaster at a lower temperature than the environment.