Flow field-flow fractionation for particle size characterization of selenium nanoparticles incubated in gastrointestinal conditions

What if you eat nanoplastics? Simulating nanoplastics fate during gastrointestinal digestion

Despite our growing awareness of micro-and nanoplastics presence in food and beverages, the fate of nanoplastics (NPs) in the human gastrointestinal tract (GIT) remains poorly investigated. Changes of nanoplastics size upon digestive conditions influence the potential of absorption through the intestine. In this study, polymer nanoparticles with different physicochemical properties (size, surface and chemistry) were submitted to gastrointestinal digestion (GID) simulated in vitro. Their agglomeration behaviour was measured with a unique set of analytical approaches, allowing to study NPs' interactions with the digestive enzymes. Smaller NPs agglomerated more, narrowing the overall particle size distribution of smaller and larger NPs. NPs of different polymers exhibited heteroagglomeration. Digestive enzymes interact with the NPs, forming large but fragile agglomerates. In presence of the enzymes, even acid-functionalized NPs, typically stable in harsh conditions, agglomerated similarly to the non-functionalized PS NPs. These results highlight the role of the GID in increasing the effective size of ingested NPs, potentially reducing their ability to pass through the cell membranes. Our findings address a critical knowledge gap in nanoplastics oral uptake potential, providing a solid technical foundation for their characterization.

Highly elastic, fatigue-resistant, antibacterial, conductive, and nanocellulose-enhanced hydrogels with selenium nanoparticles loading as strain sensors

The fabrication of highly elastic, fatigue-resistant and conductive hydrogels with antibacterial properties is highly desirable in the field of wearable devices. However, it remains challenging to simultaneously realize the above properties within one hydrogel without compromising excellent sensing ability. Herein, we fabricated a highly elastic, fatigue-resistant, conductive, antibacterial and cellulose nanocrystal (CNC) enhanced hydrogel as a sensitive strain sensor by the synergistic effect of biosynthesized selenium nanoparticles (BioSeNPs), MXene and nanocellulose. The structure and potential mechanism to generate biologically synthesized SeNPs (BioSeNPs) were systematically investigated, and the role of protease A (PrA) in enhancing the adsorption between proteins and SeNPs was demonstrated. Additionally, owing to the incorporation of BioSeNPs, CNC and MXene, the synthesized hydrogels showed high elasticity, excellent fatigue resistance and antibacterial properties. More importantly, the sensitivity of hydrogels determined by the gauge factor was as high as 6.24 when a high strain was applied (400-700 %). This study provides a new horizon to synthesize high-performance antibacterial and conductive hydrogels for soft electronics applications.

Nanoparticles as a younger member of the trace element species family - a food perspective

Speciation analysis plays a key role in understanding the biological activity and toxicity of an element. So far, classical speciation analysis focused only on the dissolved fraction of an elemental species, whereas nanoparticle forms of analytes are being widely found in consumer and industrial products. A significant contributor to human exposure to nanoparticles is through food into which nanoparticles can be incorporated from endogenous sources or they may be formed naturally in the living organisms. Nanoparticles often undergo changes in the food matrices and upon consumption, in the gastrointestinal tract, which present a significant challenge to their characterisation. Therefore, a combination of both classical and nanoparticle speciation analytical techniques is needed for the characterisation of both dissolved and particulate forms of the chemical species. This article presents and discusses the current trends in analysis of nanoparticle behaviour in the gastrointestinal tract and formation and characterisation of biogenic nanoparticles.

Dissolved metal ion removal by online hollow fiber ultrafiltration for enhanced size characterization of metal-containing nanoparticles with single-particle ICP-MS

Single particle-inductively coupled plasma mass spectrometry (SP-ICP-MS) is a powerful tool for size-characterization of metal-containing nanoparticles (MCNs) at environmentally relevant concentrations, however, coexisting dissolved metal ions greatly interfere with the accuracy of particle size analysis. The purpose of this study is to develop an online technique that couples hollow fiber ultrafiltration (HFUF) with SP-ICP-MS to improve the accuracy and size detection limit of MCNs by removing metal ions from suspensions of MCNs. Through systematic optimization of conditions including the type and concentration of surfactant and complexing agent, carrier pH, and ion cleaning time, HFUF completely removes metal ions but retains the MCNs in suspension. The optimal conditions include using a mixture of 0.05 vol.% FL-70 and 0.5 mmol/L Na₂S₂O₃ (pH = 8.0) as the carrier and 4 min as the ion cleaning time. At these conditions, HFUF-SP-ICP-MS accurately determines the sizes of MCNs, and the results agree with the size distribution determined by transmission electron microscopy, even when metal ions also are present in the sample. In addition, reducing the ionic background through HFUF also lowers the particle size detection limit with SP-ICP-MS (e.g., from 28.3 to 14.2 nm for gold nanoparticles). This size-based ion-removal principle provided by HFUF is suitable for both cations (e.g., Ag⁺) and anions (e.g., AuCl₄^-) and thus has good versatility compared to ion exchange purification and promising prospects for the removal of salts and macromolecules before single particle analysis.

A green and fast microwave-assisted synthesis of selenium nanoparticles and their characterization under gastrointestinal conditions using mass spectrometry

We present a novel microwave-assisted green synthesis of selenium nanoparticles (SeNPs) using yeast extract as source of a non-toxic reducing and capping agents. Effects of synthesis and gastrointestinal digestion conditions on the biogenic Se particle size distribution and number concentration using SP ICP MS were evaluated. The median equivalent diameter of SeNPs varied depending on the synthesis conditions. Upon incubation in simulated gastric juice, the increase of SeNPs size was observed, whereas after simulated intestinal juice addition, their size came back close to the initial value. The biomolecules contained in yeast extract, which play predominant role in the synthesis of SeNPs, were identified by non-targeted qualitative analysis using LC Orbitrap ESI MS. The use of the state-of-the-art MS techniques allowed both the comprehensive assessment of the processes leading to the SeNPs formation and the evaluation of their behavior under gastrointestinal conditions which is of utmost importance for their use as a novel selenium source.

Biogenic Selenium Nanoparticles and Their Anticancer Effects Pertaining to Probiotic Bacteria—A Review

Selenium nanoparticles (SeNPs) can be produced by biogenic, physical, and chemical processes. The physical and chemical processes have hazardous effects. However, biogenic synthesis (by microorganisms) is an eco-friendly and economical technique that is non-toxic to human and animal health. The mechanism for biogenic SeNPs from microorganisms is still not well understood. Over the past two decades, extensive research has been conducted on the nutritional and therapeutic applications of biogenic SeNPs. The research revealed that biogenic SeNPs are considered novel competitors in the pharmaceutical and food industries, as they have been shown to be virtually non-toxic when used in medical practice and as dietary supplements and release only trace amounts of Se ions when ingested. Various pathogenic and probiotic/nonpathogenic bacteria are used for the biogenic synthesis of SeNPs. However, in the case of biosynthesis by pathogenic bacteria, extraction and purification techniques are required for further useful applications of these biogenic SeNPs. This review focuses on the applications of SeNPs (derived from probiotic/nonpathogenic organisms) as promising anticancer agents. This review describes that SeNPs derived from probiotic/nonpathogenic organisms are considered safe for human consumption. These biogenic SeNPs reduce oxidative stress in the human body and have also been shown to be effective against breast, prostate, lung, liver, and colon cancers. This review provides helpful information on the safe use of biogenic SeNPs and their economic importance for dietary and therapeutic purposes, especially as anticancer agents.

Green synthesis of metallic nanoparticles using pectin as a reducing agent: a systematic review of the biological activities

CONTEXT

Pectin is a plant heteropolysaccharide that is biocompatible and biodegradable, enabling it to be an excellent reducing agent (green synthesis) for metallic nanoparticles (MNPs). Nevertheless, in the biological industry, pectin has been left behind in synthesising MNPs, for no known reason.

OBJECTIVE

To systematically review the biological activities of pectin synthesised MNPs (Pe-MNPs).

METHODS

The databases Springer Link, Scopus, ScienceDirect, Google Scholar, PubMed, Mendeley, and ResearchGate were systematically searched from the date of their inception until 10^th February 2020. Pectin, green synthesis, metallic nanoparticles, reducing agent and biological activities were among the key terms searched. The data extraction was focussed on the biological activities of Pe-MNPs and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations for systematic reviews.

RESULTS

A total of 15 studies outlined 7 biological activities of Pe-MNPs in the only three metals that have been explored, namely silver (Ag), gold (Au) and cerium oxide (CeO₂). The activities reported from the in vitro and in vivo studies were antimicrobial (9 studies), anticancer (2 studies), drug carrier (3 studies), non-toxic (4 studies), antioxidant (2 studies), wound healing (1 study) and anti-inflammation (1 study).

CONCLUSIONS

This systematic review demonstrates the current state of the art of Pe-MNPs biological activities, suggesting that Ag and Au have potent antibacterial and anticancer/chemotherapeutic drug carrier activity, respectively. Further in vitro, in vivo, and clinical research is crucial for a better understanding of the pharmacological potential of pectin synthesised MNPs.

[Application of non-stationary phase separation hyphenated with inductively coupled plasma mass spectrometry in the analysis of trace metal-containing nanoparticles in the environment]

环境中金属纳米颗粒的分析检测不仅需要关注其浓度和化学组成,还需要对其形状、粒径和表面电荷等进行表征。此外,环境中金属纳米颗粒的分析需要解决其低赋存浓度以及复杂基质干扰的难题。无固定相分离技术与电感耦合等离子体质谱(ICP-MS)的在线联用,具有较强的颗粒分离能力和较低的元素检出限,能够快速准确地提供金属纳米颗粒的粒径分布、化学组成等信息,在金属纳米颗粒的分离检测方面表现出极大的潜能。但这一联用技术尚无法获得金属纳米颗粒物的颗粒数浓度和单个颗粒的元素信息,难以判断金属纳米颗粒涂层厚度、纯度以及颗粒的均相/异相团聚行为等。新兴的单颗粒-电感耦合等离子体质谱(SP-ICP-MS)与无固定相分离技术的在线联用,可以获得金属纳米颗粒的流体动力学粒径、元素质量计算粒径和颗粒数浓度等信息,进而弥补无固定相分离与ICP-MS在线联用技术的不足。该文介绍了流体动力色谱、毛细管电泳和场流分离3种常用无固定相分离技术的分离机制和适用检测器,着重综述了无固定相分离技术与ICP-MS/SP-ICP-MS在线联用技术的特点及其在环境金属纳米颗粒分析中的应用。关于场流分离,主要介绍了可以与ICP-MS联用的沉降场流分离和流场流分离。该文还对流体动力色谱、毛细管电泳和流场流分离与ICP-MS在线联用技术的特点进行了比较。最后,该文对无固定相分离技术与ICP-MS/SP-ICP-MS在线联用技术的发展提出了展望。

Use of flow field-flow fractionation and single particle inductively coupled plasma mass spectrometry for size determination of selenium nanoparticles in a mixture

Various analytical techniques have been used for size analysis of selenium nanoparticles (SeNPs). These include flow field-flow fractionation (FlFFF), single particle inductively coupled plasma mass spectrometry (SP-ICP-MS), dynamic light scattering (DLS) and transmission electron microscopy (TEM). For hydrodynamic diameter estimation, the FlFFF technique was used and the results were compared with those analyzed by DLS. For core diameter estimation, the results obtained from SP-ICP-MS were compared with those from TEM. Two types of FlFFF channel were employed, i.e., symmetrical FlFFF (Sy-FlFFF) and asymmetrical FlFFF (Asy-FlFFF). Considering the use of FlFFF, optimization was performed on a Sy-FlFFF channel to select the most appropriate carrier liquid and membrane in order to minimize problems due to particle membrane interaction. The use of FL-70 and 10 kDa RC provided an acceptable compromise peak quality and size accuracy for all samples of SeNPs which were coated by proteins (positively charged SeNPs) and sodium dodecyl sulfate (negatively charged SeNPs). FlFFF always yielded the lower estimate of the hydrodynamic size than DLS as a reference method. The results obtained by SP-ICP-MS were consistent with the TEM method for the core diameter estimation. The results from FlFFF and the DLS reference method were significantly different as confirmed by paired t-test analysis, while the results provided by SP-ICP-MS and the TEM reference method were not significantly different. Furthermore, consecutive size analysis by SP-ICP-MS for the fractions collected from FlFFF was proposed for sizing of SeNP mixtures. The combined technique helps to improve the size analysis in the complex samples and shows more advantages than using only SP-ICP-MS.

Selenium Analysis and Speciation in Dietary Supplements Based on Next-Generation Selenium Ingredients

Selenium is essential for humans and the deficit of Se requires supplementation. In addition to traditional forms such as Se salts, amino acids, or selenium-enriched yeast supplements, next-generation selenium supplements, with lower risk for excess supplementation, are emerging. These are based on selenium forms with lower toxicity, higher bioavailability, and controlled release, such as zerovalent selenium nanoparticles (SeNPs) and selenized polysaccharides (SPs). This article aims to focus on the existing analytical systems for the next-generation Se dietary supplement, providing, at the same time, an overview of the analytical methods available for the traditional forms. The next-generation dietary supplements are evaluated in comparison with the conventional/traditional ones, as well as the analysis and speciation methods that are suitable to reveal which Se forms and species are present in a dietary supplement. Knowledge gaps and further research potential in this field are highlighted. The review indicates that the methods of analysis of next-generation selenium supplements should include a step related to chemical species separation. Such a step would allow a proper characterization of the selenium forms/species, including molecular mass/dimension, and substantiates the marketing claims related to the main advantages of these new selenium ingredients.