Nano-enabled agrochemicals/materials: Potential human health impact, risk assessment, management strategies and future prospects.

Nanotechnology is a rapidly developing technology that will have a significant impact on product development in the next few years. The technology is already being employed in cutting-edge cosmetic and healthcare products. Nanotechnology and nanoparticles have a strong potential for product and process innovation in the food industrial sector. This is already being demonstrated by food product availability made using nanotechnology. Nanotechnologies will have an impact on food security, packaging materials, delivery systems, bioavailability, and new disease detection materials in the food production chain, contributing to the UN Millennium Development Goals targets. Food products using nanoparticles are already gaining traction into the market, with an emphasis on online sales. This means that pre- and post-marketing regulatory frameworks and risk assessments must meet certain standards. There are potential advantages of nanotechnologies for agriculture, consumers and the food industry at large as they are with other new and growing technologies. However, little is understood about the safety implications of applying nanotechnologies to agriculture and incorporating nanoparticles into food. As a result, policymakers and scientists must move quickly, as regulatory systems appear to require change, and scientists should contribute to these adaptations. Their combined efforts should make it easier to reduce health and environmental impacts while also promoting the economic growth of nanotechnologies in the food supply chain. This review highlighted the benefits of a number of nano enabled agrochemicals/materials, the potential health impacts as well as the risk assessment and risk management for nanoparticles in the agriculture and food production chain.

Distribution, source, and environmental risk assessment of phthalate esters (PAEs) in water, suspended particulate matter, and sediment of a typical Yangtze River Delta City, China.

Phthalates (PAEs) in drinking water sources such as the Yangtze River in developing countries had aroused widespread concern. Here, the water, suspended particulate matter (SPM), and sediment samples were collected from 15 sites in wet and dry seasons in Zhenjiang, for the determination of six PAEs (DMP, DEP, DIBP, DBP, DEHP, and DOP) using the solid-phase extraction (SPE) or ultrasonic extraction coupled with gas chromatography-mass spectrometry (GC-MS). The total concentrations of six PAEs (Σ6PAEs) spanned a range of 2.65-39.31 µg L-1 in water, 1.97-34.10 µg g-1 in SPM, and 0.93-34.70 µg g-1 in sediment. The partition coefficients (Kd1) of PAEs in water and SPM phase ranged from 0.004 to 3.36 L g-1 in the wet season and from 0.12 to 2.84 L g-1 in the dry season. Kd2 of PAEs in water and sediment phase was 0.001-9.75 L g-1 in the wet season and 0.006-8.05 L g-1 in the dry season. The dominant PAEs were DIBP, DBP, and DEHP in water and SPM, DIBP, DEHP, and DOP in sediment. The concentration of DBP in water exceeded the China Surface Water Standard. The discharge of domestic sewage and industrial wastewater might be the main potential sources of PAEs. The risk quotient (RQ) method used for the risk assessment revealed that DBP (0.01 < RQ < 1) posed a medium risk, while DIBP and DEHP (RQ > 1) posed a high environmental risk in water, DIBP (RQ > 1) also showed a high risk in sediment.

NIR nanoprobe-facilitated cross-referencing manifestation of local disease biology for dynamic therapeutic response assessment.

Pharmacological interventions for effective treatment require opportune, dynamic and accurate manifestation of pathological status. Traditional clinical techniques relying on biopsy-based histological examinations and blood tests are dramatically restricted due to their invasiveness, unsatisfactory precision, non-real-time reporting and risk of complications. Although current strategies through molecular imaging enable non-invasive and spatiotemporal mapping of pathological changes in intact organisms, environment-activatable, sensitive and quantitative sensing platforms, especially for dynamic feedback of the therapeutic response, are still urgently desired in practice. Herein, we innovatively integrate deep-tissue penetrable multispectral optoacoustic tomography (MSOT) and near-infrared (NIR) optical imaging based technology by tailoring a free radical-responsive chromophore with photon-upconverting nanocrystals. During the therapeutic process, the specific reactions between the drug-stimulated reactive oxygen species (ROS) and radical-sensitive probes result in an absorption shift, which can be captured by MSOT. Meanwhile, the radical-triggered reaction also induces multispectral upconversion luminescence (UCL) responses that exhibit the opposite trend in comparison to MSOT. Such reversed-ratiometric dual-modal imaging outcomes provide an ideal cross-referencing system that guarantees the maximum sensing specificity and sensitivity, thus enabling precise disease biology evaluation and treatment assessments in vivo.

Purification, characterization and immunoregulatory activity of a polysaccharide isolated from Hibiscus sabdariffa L.

BACKGROUND: Hibiscus sabdariffa L. is not only used traditionally as a component of herbal drinks, beverages and flavoring agents but also as a herbal medicine in the drug industry. Bioactive polysaccharides are important constituents of H. sabdariffa that may contribute to the plant's beneficial effects. This study was designed to investigate the structural characteristics of a water-soluble polysaccharide from H. sabdariffa, HSP41, and its immunoregulatory activity on RAW264.7 cells. RESULTS: HSP41 was mainly composed of arabinose, xylose and mannose at a molar ratio of 1:1.34:15.6, with an average molecular weight of 3.3 × 105 Da. Fourier transform infrared (FTIR) spectra exhibited absorption peaks characteristic of HSP41. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed the amorphous form and aggregation conformation of HSP41 respectively. HSP41 significantly induced interleukin 1ß (IL-1ß) and inducible nitric oxide synthase (iNOS) expression in RAW264.7 cells in vitro, promoting an increase in nuclear factor kB p65 (NF-kB p65) levels in the nucleus. CONCLUSION: The results indicated that HSP41 up-regulated the immune response by stimulating RAW264.7 cell activity. HSP41, a promising immunoregulator, possibly contributes to the health benefits of H. sabdariffa and might have potential applications in health food or medicine. © 2016 Society of Chemical Industry.

A highly sensitive signal-amplified gold nanoparticle-based electrochemical immunosensor for dibutyl phthalate detection.

A simple and signal-amplified, label-free electrochemical impedimetric immunosensor for dibutyl phthalate (DBP), a type of phthalate ester, was developed using gold nanoparticles (AuNPs) induced signal amplification. The approach was based on an indirectly competitive binding system of coating antigen that coated on antigen/chitosan/MWCNTs@GONRs/GCE (modified electrodes), target (DBP) and anti-DBP antibody. Signal amplification was performed via the enlargement of AuNPs through NADH-promoted catalytic precipitation, which caused a marked increase in the electron-transfer resistance and electrostatic repulsion after an AuNP-labeled second antibody conjugated to anti-DBP. Under the optimized conditions, this method displayed: (i) low detection limits (7ng/mL, 10 times lower than the traditional ELISA method using the same antibody); (ii) satisfactory accuracy (recoveries, 86.0-120.4%) and agreement with corresponding ELISA method; (iii) high tolerance to some environmental interferents; and (iv) low cost and low sample consumption (6µL). Our results demonstrate the great potential and high efficiency of this immunosensor in practical applications for the cost-effective and sensitive monitoring of DBP in aquatic environments.

A multivariate assessment of innate immune-related gene expressions due to exposure to low concentration individual and mixtures of four kinds of heavy metals on zebrafish (Danio rerio) embryos.

Concerns over the potential health effects of mixtures of low concentration heavy metals on living organisms keep growing by the day. However, the toxicity of low concentration metal mixtures on the immune system of fish species has rarely been investigated. In this study, the zebrafish model was employed to investigate the effect on innate immune and antioxidant-related gene expressions, on exposure to environmentally relevant concentrations of individual and mixtures of Pb (0.01 mg/L), Hg (0.001 mg/L), As (0.01 mg/L) and Cd (0.005 mg/L). Messenger-RNA (mRNA) levels of IL1ß, TNF-α, IFNγ, Mx, Lyz, C3B and CXCL-Clc which are closely associated with the innate immune system were affected after exposing zebrafish embryos to metals for 120 h post fertilization (hpf). Individual and mixtures of metals exhibited different potentials to modulate innate-immune gene transcription. IL1ß genes were significantly up regulated on exposure to Pb + As (2.01-fold) and inhibited on exposure to Pb + Hg + Cd (0.13-fold). TNF-α was significantly inhibited on exposure to As (0.40-fold) and Pb + As (0.32-fold) compared to control. Metal mixtures generally up regulated IFNγ compared to individual metals. Additionally, antioxidant genes were affected, as CAT and GPx gene expressions generally increased, whiles Mn-SOD and Zn/Cu-SOD reduced. Multivariate analysis showed that exposure to individual metals greatly influenced modulation of innate immune genes; whiles metal mixtures influenced antioxidant gene expressions. This suggests that beside oxidative stress, there may be other pathways influencing gene expressions of innate immune and antioxidant-related genes. Low concentration heavy metals also affect expression of development-related (wnt8a and vegf) genes. Altogether, the results of this study clearly demonstrate that low concentration individual and mixtures of metals in aquatic systems will greatly influence the immune system. It is indicative that mechanisms associated with toxicity of metal mixtures is complex, however, further studies to elucidate them are ongoing in our research laboratory.

Assessment of immunotoxicity of dibutyl phthalate using live zebrafish embryos.

This study set out to understand the immune-toxic effects of dibutyl phthalate (DBP) using transgenic, albino or AB line zebrafish. Zebrafish embryos were exposed to different concentrations of DBP, and the immune cells formation, phagocytosis ability were measured after a short-term exposure to DBP for 6 h post-fertilization (hpf) to 72 or 96 hpf. Exposure to DBP was found to inhibit the neutrophils and macrophage formation in a concentration-dependent manner. The ability of macrophage phagocytosis was all decreased after exposure to DBP, indicating the occurrence of immunotoxicity. The respiratory burst was induced, and the transcription levels of T/B cell-related genes rag1/2 were up-regulated. The overall results indicate that DBP in aquatic environment greatly influence the immune system in fish, and zebrafish embryos can serve as a reliable model for the developmental immunotoxicity of toxic-chemicals.

Toxicity assessment due to sub-chronic exposure to individual and mixtures of four toxic heavy metals.

Humans are exposed to a cocktail of heavy metal toxicants in the environment. Though heavy metals are deleterious, there is a paucity of information on toxicity of low dose mixtures. In this study, lead (Pb) (0.01mg/L), mercury (Hg) (0.001mg/L), cadmium (Cd) (0.005mg/L) and arsenic (As) (0.01mg/L) were administered individually and as mixtures to 10 groups of 40 three-week old mice (20 males and 20 females), for 120 days. The study established that low dose exposures induced toxicity to the brain, liver, and kidney of mice. Metal mixtures showed higher toxicities compared to individual metals, as exposure to low dose Pb+Hg+Cd reduced brain weight and induced structural lesions, such as neuronal degeneration in 30-days. Pb+Hg+Cd and Pb+Hg+As+Cd exposure induced hepatocellular injury to mice evidenced by decreased antioxidant activities with marginal increases in MDA. These were accentuated by increases in ALT, AST and ALP. Interactions in metal mixtures were basically synergistic in nature and exposure to Pb+Hg+As+Cd induced renal tubular necrosis in kidneys of mice. This study underlines the importance of elucidating the toxicity of low dose metal mixtures so as to protect public health.