A new angle on dynamic depolarized light scattering: number-averaged size distribution of nanoparticles in focus

Size polydispersity is a common phenomenon that strongly influences the physicochemical properties of nanoparticles (NPs). We present an analytical approach that is universally applicable to characterizing optically anisotropic round NPs and determines directly the number-averaged size distribution and polydispersity via depolarized dynamic light scattering (DDLS). To demonstrate, we use aqueous suspensions of Au NPs of different sizes and surface functionalization

Quantifying nanoparticle cellular uptake: which method is best?

As the range of engineered nanoparticles (NPs) designed as specific carriers increases, for example for cell targeting and drug delivery, the question on how many NPs are interacting or are taken up by cells is becoming increasingly important for any potential biomedical application. On one hand, the delivered dose of such NPs to the targeted cells is a key parameter in the assessment of their efficiency to perform the desired action (e.g., deliver the therapeutic substance or induce a specific effect), on the other hand, the assessment of intracellular NPs is crucial also from the safety aspect as NPs might come unintentionally in contact by untargeted cells. Particularly from the regulative perspective, it is important that reproducible and reliable analytical methods for the intracellular quantification of NPs are available at an early stage in the development in order to correlate the cell burden of NPs with their possible effects at a cellular level

Plasmonic nanoparticles and their characterization in physiological fluids

Nanoparticles possess unique properties beyond that of classical materials, and while these properties can be used for designing a dedicated functionality, they may also pose a problem to living organisms, to human health and the environment. The specific primary routes by which nanoparticles may interact with the human body include inhalation, injection, ingestion and application to the skin. Independent of the entry route, the particles inevitably encounter a complex physiological fluid populated with e.g. proteins, vitamins, lipids and salts/ions. Different consequences of such an encounter may include formation of a surface-bound protein layer, particle dissolution or aggregation, which are expected to have a crucial impact on cellular interaction. Understanding cellular responses to nanoparticle interactions starts with understanding particle behavior in physiological fluids. Nanoparticles are now available in practically any size, shape and functionalization, to promote distinct optical, magnetic, and physico-chemical properties, making the prediction of their behavior, in physiological fluids, not a trivial task. Characterization has therefore become of paramount importance. In this review, we give an overview about the diversity of physiological fluids as well as present an inventory of the most relevant experimental techniques used to study plasmonic nanoparticles

Exposure to silver nanoparticles affects viability and function of natural killer cells, mostly via the release of ions.

Natural killer (NK) cells play a crucial role in linking innate and adaptive immune responses, especially during viral infections and tumor surveillance. They have two major effector functions: the killing of stressed/abnormal cells and the release of cytokines. Their activity is regulated via inhibitory and activating surface receptors. At the same time that the production and use of engineered nanoparticles is steadily increasing, the risk for exposure to silver nanoparticles (AgNPs) from consumer products or biomedical applications is growing. Given this, we assessed the effects of 20-nm big AgNPs on NK cells, which represent an important part of the immune system. Our study involved overnight exposure of human blood NK cells to different concentrations of AgNPs, and silver (Ag) ion controls, and analyzing them for viability, surface receptor expression, intracellular markers, cytokine release, and killing potential. Exposure to AgNPs, but not to Ag ion controls, reduced the viability and the cytotoxic potential after polyriboinosinic-polyribocytidylic acid stimulation of NK cells and increased the expression of the inhibitory receptor CD159a. Exposure to AgNPs and Ag ion controls reduced the expression of the activating receptors CD335 and of CD16 and increased the expression of the activating receptor CD314. Overall, exposure to AgNPs changes NK cells' function and phenotype and may present a risk for modulating human immune responses, which should be further investigated

Compositional attributes and fatty acid profile of lamb meat from Iberian local breeds

This study aimed to compare lamb meat composition from five Iberian breeds raised in their typical rearing systems and to reveal trends in compositional meat attributes due to breed or production system. The meat quality of 153 animals was analysed. The combined effect of breed × production system produced significant differences in lamb meat quality. Meat from the extensively-reared Bordaleira-de-Entre-Douro-e-Minho (BEDM) and Gallega breeds had elevated amounts of n-3 PUFAs, tocopherol content and favourable n-6/n-3 ratio. Meat from lambs grown under extensive and semi-extensive systems presented higher content of conjugated linoleic acid than the two breeds reared intensively. The meat of commercial breed (INRA401) was characterised by higher content of protein and MUFAs and lower atherogenic potential than the breeds reared in extensive and semi-extensive systems. Principal component analysis demonstrated that meat from extensively raised lambs was associated to higher SFA, CLA, α-tocopherol, n-3, atherogenic index and cholesterol content, but lower intramuscular fat and retinol content, MUFA and n-6/n-3.The authors are grateful to EU ERA-NET programme and the Portuguese Foundation for Science and Technology (FCT) for funding the project “EcoLamb–Holistic Production to Reduce the Ecological Footprint of Meat (SusAn/0002/2016). CIMO authors are grateful to FCT and FEDER under Programme PT2020 for financial support to CIMO (UIDB/00690/2020). Dr. Gonzales-Barron acknowledges the national funding by FCT, P.I., through the Institutional Scientific Employment Programme contract. Jos´e M. Lorenzo is member of the HealthyMeat network, funded by CYTED (ref. 119RT0568).info:eu-repo/semantics/publishedVersio

Characterizing nanoparticles in complex biological media and physiological fluids with depolarized dynamic light scattering

Light scattering is one of the few techniques available to adequately characterize suspended nanoparticles (NPs) in real time and in situ. However, when it comes to NPs in multicomponent and optically complex aqueous matrices – such as biological media and physiological fluids – light scattering suffers from lack of selectivity, as distinguishing the relevant optical signals from the irrelevant ones is very challenging. We meet this challenge by building on depolarized scattering: Unwanted signals from the matrix are completely suppressed. This approach yields information with an unprecedented signal-to-noise ratio in favour of the NPs and NP-biomolecule corona complexes, which in turn opens the frontier to scattering-based studies addressing the behaviour of NPs in complex physiological/biological fluids

Influence of the production system (Intensive vs. extensive) at farm level on proximate composition and volatile compounds of portuguese lamb meat

Today’s society demands healthy meat with a special emphasis on integrated animal husbandry combined with the concern for animal welfare. In this sense, the raising of lambs in an extensive system has been one of the most common practices, which results in meats with high nutritional value. However, both the production system and the diet play a fundamental role in the chemical composition of the meat, which has a direct impact on the content of volatile compounds. Thus, the aim of this study was to determine the effect of two production systems (intensive and extensive) on the chemical composition and volatile profile of lamb meat. Twenty-eight lambs of the Bordaleira-de-Entre-Douro-e-Minho (BEDM) sheep breed were raised for meat production under the intensive or extensive system and were fed with concentrate and pasture, respectively. All animals were carried out in the muscle longissimus thoracis et lumborum. Results evidenced that all the composition parameters were affected by the production system. Extensively-reared lambs produced meat with the highest fat and protein contents, while these animals had the lowest percentages of moisture and ash. Similarly, the total content of volatile compounds was affected (p lt 0.05) by the production system and were higher in the meat of lambs reared extensively. Furthermore, the content of total acids, alcohols, aldehydes, esters, ethers, furans and sulfur compounds as well as most of the individual compounds were also affected (p lt 0.05) by the production system, whereas total hydrocarbons and ketones were not affected (p gt 0.05). As a general conclusion, the production system had very high influence not only in proximate composition but also in the volatile compounds.Noemí Echegaray acknowledges Consellería de Cultura, Educación e Ordenación Universitaria (Xunta de Galicia) for granting with a predoctoral scholarship (Grant number IN606A-2018/002). Rubén Domínguez, Laura Purriños, Roberto Bermúdez and José M. Lorenzo are members of the HealthyMeat network and funded by CYTED (ref. 119RT0568). CIMO authors are grateful to FCT and FEDER under Programme PT2020 for the financial support to CIMO (UIDB/00690/2020). Gonzales-Barron acknowledges the national funding by FCT, P.I., through the Institutional Scientific Employment Programme contract.info:eu-repo/semantics/publishedVersio

Translocation of gold nanoparticles across the lung epithelial tissue barrier: Combining in vitro and in silico methods to substitute in vivo experiments

The lung epithelial tissue barrier represents the main portal for entry of inhaled nanoparticles (NPs) into the systemic circulation. Thus great efforts are currently being made to determine adverse health effects associated with inhalation of NPs. However, to date very little is known about factors that determine the pulmonary translocation of NPs and their subsequent distribution to secondary organs.Methods: A novel two-step approach to assess the biokinetics of inhaled NPs is presented. In a first step, alveolar epithelial cellular monolayers (CMLs) at the air-liquid interface (ALI) were exposed to aerosolized NPs to determine their translocation kinetics across the epithelial tissue barrier. Then, in a second step, the distribution to secondary organs was predicted with a physiologically based pharmacokinetic (PBPK) model. Monodisperse, spherical, well-characterized, negatively charged gold nanoparticles (AuNP) were used as model NPs. Furthermore, to obtain a comprehensive picture of the translocation kinetics in different species, human (A549) and mouse (MLE-12) alveolar epithelial CMLs were exposed to ionic gold and to various doses (i.e., 25, 50, 100, 150, 200 ng/cm 2 ) and sizes (i.e., 2, 7, 18, 46, 80 nm) of AuNP, and incubated post-exposure for different time periods (i.e., 0, 2, 8, 24, 48, 72 h).Results: The translocation kinetics of the AuNP across A549 and MLE-12 CMLs was similar. The translocated fraction was (1) inversely proportional to the particle size, and (2) independent of the applied dose (up to 100 ng/cm 2 ). Furthermore, supplementing the A549 CML with two immune cells, i.e., macrophages and dendritic cells, did not significantly change the amount of translocated AuNP. Comparison of the measured translocation kinetics and modeled biodistribution with in vivo data from literature showed that the combination of in vitro and in silico methods can accurately predict the in vivo biokinetics of inhaled/instilled AuNP.Conclusion: Our approach to combine in vitro and in silico methods for assessing the pulmonary translocation and biodistribution of NPs has the potential to replace short-term animal studies which aim to assess the pulmonary absorption and biodistribution of NPs, and to serve as a screening tool to identify NPs of special concern

Fatty acid profile of lamb meat from two portuguese autochthonous breeds

In Portugal, sheep and goat meat production accounts for 2.8% of the total meat production in the country; and it is capable of supplying approximately 82% of the domestic demand (INE, 2015). Churra-Galega-Bragançana (CGB) and Bordaleira-entre-Douro-e-Minho (BEDM) are two native breeds of the north of Portugal, classified as endangered lamb breeds. These breeds are exploited for meat production, the former in the Atlantic bio-region and the latter in the Mediterranean area. Production factors, such as breed, have a great influence on nutritional aspects related with the content and quality of fat and fatty acid profile (Frank et al., 2016), which are considered important quality indicators that have a great influence on consumer acceptability (Andersen et al., 2005), especially nowadays as consumers have become increasingly concerned about health and the relationship between meat consumption and saturated fatty acids (Leroy and De Smet, 2019). These autochthonous breeds constitute an important genetic heritage that must be preserved, so assessing their fatty acid profile will allow a correct characterization of these breeds and their products.info:eu-repo/semantics/publishedVersio

Distribution of polymer-coated gold nanoparticles in a 3D lung model and indication of apoptosis after repeated exposure

Aim: The distribution and impact of aerosol-delivered gold nanoparticles (AuNPs) functionalized with a mixture of aminated-polyvinyl alcohol and amino-PEG ([polyvinyl alcohol/PEG]-NH2) upon repeated administration onto a 3D lung model were explored. Materials & methods: AuNPs were aerosolized and uptake and epithelial translocation was assessed by inductively coupled plasma optical-emission spectroscopy, flow cytometry and electron microscopy. In addition, cytotoxicity, apoptosis and proinflammation were evaluated. Results: Repeated AuNP aerosolization resulted in NP accumulation in macrophages and epithelial cells. Dendritic cells demonstrated substantial NP internalization after single administration which was reduced in later time points. No cytotoxicity or proinflammation was observed but after 96 h significant apoptosis was induced by the polymer coating. Conclusion: These results indicate the importance of repeated exposures in addressing potential effects of NPs