Cellulose Hydrogels Containing Geraniol and Icaridin Encapsulated in Zein Nanoparticles for Arbovirus Control.

The most important arboviruses are those that cause dengue, yellow fever, chikungunya, and Zika, for which the main vector is the Aedes aegypti mosquito. The use of repellents is an important way to combat mosquito-borne pathogens. In this work, a safe method of protection employing a repellent was developed based on a slow release system composed of zein nanoparticles containing the active agents icaridin and geraniol incorporated in a cellulose gel matrix. Analyses were performed to characterize the nanoparticles and the gel formulation. The nanoparticles containing the repellents presented a hydrodynamic diameter of 229 ± 9 nm, polydispersity index of 0.38 ± 0.10, and zeta potential of +29.4 ± 0.8 mV. The efficiencies of encapsulation in the zein nanoparticles exceeded 85% for icaridin and 98% for geraniol. Rheological characterization of the gels containing nanoparticles and repellents showed that the viscoelastic characteristic of hydroxypropylmethylcellulose gel was preserved. Release tests demonstrated that the use of nanoparticles in combination with the gel matrix led to improved performance of the formulations. Atomic force microscopy analyses enabled visualization of the gel network containing the nanoparticles. Cytotoxicity assays using 3T3 and HaCaT cell cultures showed low toxicity profiles for the active agents and the nanoparticles. The results demonstrated the potential of these repellent systems to provide prolonged protection while decreasing toxicity.

Nanotechnology Potential in Seed Priming for Sustainable Agriculture.

Our agriculture is threatened by climate change and the depletion of resources and biodiversity. A new agriculture revolution is needed in order to increase the production of crops and ensure the quality and safety of food, in a sustainable way. Nanotechnology can contribute to the sustainability of agriculture. Seed nano-priming is an efficient process that can change seed metabolism and signaling pathways, affecting not only germination and seedling establishment but also the entire plant lifecycle. Studies have shown various benefits of using seed nano-priming, such as improved plant growth and development, increased productivity, and a better nutritional quality of food. Nano-priming modulates biochemical pathways and the balance between reactive oxygen species and plant growth hormones, resulting in the promotion of stress and diseases resistance outcoming in the reduction of pesticides and fertilizers. The present review provides an overview of advances in the field, showing the challenges and possibilities concerning the use of nanotechnology in seed nano-priming, as a contribution to sustainable agricultural practices.

Can atrazine loaded nanocapsules reduce the toxic effects of this herbicide on the fish Prochilodus lineatus? A multibiomarker approach.

Atrazine (ATZ) is a widely used herbicide that has the potential to contaminate the environment and cause deleterious effects on non-target organisms. Release systems for ATZ have been developed to minimize this contamination, such as nanocapsules prepared with poly (ε-caprolactone) (PCL). The objective of this work was to investigate the effects of nanoencapsulated ATZ compared to ATZ on biomarkers of the freshwater teleost Prochilodus lineatus. The fish were exposed for 24 and 96 h to nanoencapsulated ATZ (nATZ) and atrazine (ATZ) at concentrations of 2 and 20 µg L-1, just to the PCL nanocapsules without the herbicide (NANO) in the corresponding amounts or only to dechlorinated water (CTR). The results showed that nATZ was less toxic compared to ATZ, as it did not promote an increase in glycemia, alterations in antioxidants, nor in carbonic anhydrase enzyme activity, and no increase in the frequency of micronuclei and other nuclear erythrocyte abnormalities either. However, exposure to nATZ, as well as to ATZ and PCL nanocapsules, resulted in a reduction in hemoglobin content, increase in erythrocyte DNA damage, as well as changes in Ca2+-ATPase activity, leading to a decrease in plasma Ca+2. The Integrated Biomarker Response Index (IBR) depicted that exposure to ATZ promoted changes in a greater number of biomarkers compared to nATZ, indicating that the nanoencapsulation of the herbicide protected the animal from the effects of ATZ.

Chrysophanol: A Natural Anthraquinone with Multifaceted Biotherapeutic Potential.

Chrysophanol is a unique anthraquinone having broad-spectrum therapeutic potential along with ecological importance. It is the first polyketide that has been reported to be biosynthesized in an organism-specific manner. The traditional Chinese and Korean medicinal systems provide evidence of the beneficial effects of chrysophanol on human health. The global distribution of chrysophanol encountered in two domains of life (bacteria and eukaryota) has motivated researchers to critically evaluate the properties of this compound. A plethora of literature is available on the pharmacological properties of chrysophanol, which include anticancer, hepatoprotective, neuroprotective, anti-inflammatory, antiulcer, and antimicrobial activities. However, the pharmacokinetics and toxicity studies on chrysophanol demand further investigations for it to be used as a drug. This is the first comprehensive review on the natural sources, biosynthetic pathways, and pharmacology of chrysophanol. Here we reviewed recent advancements made on the pharmacokinetics of the chrysophanol. Additionally, we have highlighted the knowledge gaps of its mechanism of action against diseases and toxicity aspects.

Evaluation of the genotoxicity of cellulose nanofibers.

BACKGROUND: Agricultural products and by products provide the primary materials for a variety of technological applications in diverse industrial sectors. Agro-industrial wastes, such as cotton and curaua fibers, are used to prepare nanofibers for use in thermoplastic films, where they are combined with polymeric matrices, and in biomedical applications such as tissue engineering, amongst other applications. The development of products containing nanofibers offers a promising alternative for the use of agricultural products, adding value to the chains of production. However, the emergence of new nanotechnological products demands that their risks to human health and the environment be evaluated. This has resulted in the creation of the new area of nanotoxicology, which addresses the toxicological aspects of these materials. PURPOSE AND METHODS: Contributing to these developments, the present work involved a genotoxicological study of different nanofibers, employing chromosomal aberration and comet assays, as well as cytogenetic and molecular analyses, to obtain preliminary information concerning nanofiber safety. The methodology consisted of exposure of Allium cepa roots, and animal cell cultures (lymphocytes and fibroblasts), to different types of nanofibers. Negative controls, without nanofibers present in the medium, were used for comparison. RESULTS: The nanofibers induced different responses according to the cell type used. In plant cells, the most genotoxic nanofibers were those derived from green, white, and brown cotton, and curaua, while genotoxicity in animal cells was observed using nanofibers from brown cotton and curaua. An important finding was that ruby cotton nanofibers did not cause any significant DNA breaks in the cell types employed. CONCLUSION: This work demonstrates the feasibility of determining the genotoxic potential of nanofibers derived from plant cellulose to obtain information vital both for the future usage of these materials in agribusiness and for an understanding of their environmental impacts.

Evaluation of the genotoxicity of chitosan nanoparticles for use in food packaging films.

The use of nanoparticles in food packaging has been proposed on the basis that it could improve protection of foods by, for example, reducing permeation of gases, minimizing odor loss, and increasing mechanical strength and thermal stability. Consequently, the impacts of such nanoparticles on organisms and on the environment need to be investigated to ensure their safe use. In an earlier study, Moura and others (2008a) described the effect of addition of chitosan (CS) and poly(methacrylic acid) (PMAA) nanoparticles on the mechanical properties, water vapor, and oxygen permeability of hydroxypropyl methylcellulose films used in food packaging. Here, the genotoxicity of different polymeric CS/PMAA nanoparticles (size 60, 82, and 111 nm) was evaluated at different concentration levels, using the Allium cepa chromosome damage test as well as cytogenetic tests employing human lymphocyte cultures. Test substrates were exposed to solutions containing nanoparticles at polymer mass concentrations of 1.8, 18, and 180 mg/L. Results showed no evidence of DNA damage caused by the nanoparticles (no significant numerical or structural changes were observed), however the 82 and 111 nm nanoparticles reduced mitotic index values at the highest concentration tested (180 mg/L), indicating that the nanoparticles were toxic to the cells used at this concentration. In the case of the 60 nm CS/PMAA nanoparticles, no significant changes in the mitotic index were observed at the concentration levels tested, indicating that these particles were not toxic. The techniques used show promising potential for application in tests of nanoparticle safety envisaging the future use of these materials in food packaging.

Differential effects of uncharged aminoamide local anesthetics on phospholipid bilayers, as monitored by 1H-NMR measurements.

We have collected evidences of a "transient site" for the local anesthetics (LA) lidocaine, etidocaine, bupivacaine and mepivacaine in sonicated egg phosphatidylcholine (EPC) vesicles. The effects of the uncharged anesthetic species at a fixed LA/EPC ratio inside the bilayer were measured by chemical shifts (C.S.) and longitudinal relaxation times (T(1)) of the lipid hydrogens. Two sort of changes were detected: (I) decrease, indicating specific orientation of the LA aromatic ring (measured as up-field C.S. changes by the short-range ring-current effect) and less rotational freedom (smaller T(1) values) for EPC hydrogens such as the two glycerol-CH(2) and the choline-CH(2) bound to the PO(4-) group, probably due to the nearby presence of the LA; (II) increase, indicating the aromatic ring is now perpendicular to the orientation observed before (causing down-field changes in C.S.) and larger T(1) values for all the choline and glycerol hydrogens, as a result of LA insertion behind these well-organized bilayer regions. The less hydrophobic, linear and nonlinear (lidocaine and mepivacaine, respectively) aminoamide analogs provide similar effects-described in I; their hydrophobic counterparts (etidocaine and bupivacaine) also produced comparable effects (depicted in II). The preferential positioning and orientation of each LA inside the bilayer is then determined by its hydrophobic and steric properties. We propose that this "transient site" in the lipid milieu exists also in biological membranes, where it can modulates the access of the uncharged LA species to its site(s) of action in the voltage-gated sodium channel.