TY - JOUR T1 - Determination of the Transport Efficiency in spICP-MS Analysis Using Conventional Sample Introduction Systems: An Interlaboratory Comparison Study JF - Nanomaterials Y1 - 2022 A1 - Otmar Geiss A1 - Ivana Bianchi A1 - Guillaume Bucher A1 - Eveline Verleysen A1 - Frederic Brassinne A1 - Jan Mast A1 - Katrin Loeschner A1 - Lucas Givelet A1 - Francesco Cubadda A1 - Francesca Ferraris A1 - Andrea Raggi A1 - Francesca Iacoponi A1 - Peters, Ruud J B A1 - Anna Undas A1 - Alexandra Müller A1 - Ann-Katrin Meinhardt A1 - Birgit Hetzer A1 - Volker Gräf A1 - Antonio R. Montoro Bustos A1 - Josefa Barrero-Moreno VL - 12 CP - 4 M3 - 10.3390/nano12040725 ER - TY - JOUR T1 - Titanium dioxide particles frequently present in face masks intended for general use require regulatory control JF - Scientific Reports Y1 - 2022 A1 - Eveline Verleysen A1 - Ledecq, Marina A1 - Lisa Siciliani A1 - Karlien Cheyns A1 - Christiane Vleminckx A1 - Marie-Noelle Blaude A1 - Sandra De Vos A1 - Frederic Brassinne A1 - Frederic Van Steen A1 - Régis Nkenda A1 - Ronny Machiels A1 - Nadia Waegeneers A1 - Joris Van Loco A1 - Jan Mast VL - 12 CP - 1 M3 - 10.1038/s41598-022-06605-w ER - TY - JOUR T1 - Towards a generic protocol for measuring the constituent particle size distribution of E171 in food by electron microscopy JF - Food Control Y1 - 2022 A1 - Eveline Verleysen A1 - Frederic Brassinne A1 - Frederic Van Steen A1 - Nadia Waegeneers A1 - Karlien Cheyns A1 - Ronny Machiels A1 - Stella Mathioudaki A1 - Isaac Ojea Jimenez A1 - Ledecq, Marina A1 - Jan Mast VL - 132 M3 - 10.1016/j.foodcont.2021.108492 ER - TY - JOUR T1 - Particle size analysis of pristine food-grade titanium dioxide and E 171 in confectionery products: Interlaboratory testing of a SP-ICP-MS screening method and confirmation with transmission electron microscopy. JF - Food Control Y1 - 2021 A1 - Otmar Geiss A1 - Ivana Bianchi A1 - Chiara Senaldi A1 - Guillaume Bucher A1 - Eveline Verleysen A1 - Nadia Waegeneers A1 - Frederic Brassinne A1 - Jan Mast A1 - Katrin Loeschner A1 - Janja Vidmar A1 - Federica Aureli A1 - Francesco Cubadda A1 - Andrea Raggi A1 - Francesca Iacoponi A1 - Ruud Peters A1 - Anna Undas A1 - Alexandra Müller A1 - Ann-Katrin Meinhardt A1 - Elke Walz A1 - Volker Gräf A1 - Josefa Barrero-Moreno KW - confectionery KW - E 171 KW - Food-grade titanium dioxide KW - Single-particle ICP-MS KW - VALIDATION AB -

Titanium dioxide is a white colourant authorised as food additive E 171 in the EU, where it is used in a range of alimentary products. As these materials may contain a fraction of particulates with sizes below 100 nm and current EU regulation requires specific labelling of food ingredient to indicate the presence of engineered nanomaterials there is now a need for standardised and validated methods to appropriately size and quantify (nano)particles in food matrices. A single-particle inductively coupled plasma mass spectrometry (spICP-MS) screening method for the determination of the size distribution and concentration of titanium dioxide particles in sugar-coated confectionery and pristine food-grade titanium dioxide was developed. Special emphasis was placed on the sample preparation procedure, crucial to reproducibly disperse the particles before analysis. The transferability of this method was tested in an interlaboratory comparison study among seven experienced European food control and food research laboratories equipped with various ICP-MS instruments and using different software packages. The assessed measurands included the particle mean diameter, the most frequent diameter, the percentage of particles (in number) with a diameter below 100 nm, the particles' number concentration and a number of cumulative particle size distribution parameters (D0, D10, D50, D99.5, D99.8 and D100). The evaluated method's performance characteristics were, the within-laboratory precision, expressed as the relative repeatability standard deviation (RSDr), and the between-laboratory precision, expressed as the relative reproducibility standard deviation (RSDR). Transmission electron microscopy (TEM) was used as a confirmatory technique and served as the basis for bias estimation. The optimisation of the sample preparation step showed that when this protocol was applied to the relatively simple sample food matrices used in this study, bath sonication turned out to be sufficient to reach the highest, achievable degree of dispersed constituent particles. For the pristine material, probe sonication was required. Repeatability and reproducibility were below 10% and 25% respectively for most measurands except for the lower (D0) and the upper (D100) bound of the particle size distribution and the particle number concentration. The broader distribution of the lower and the upper bounds could be attributed to instrument-specific settings/setups (e.g. the timing parameters, the transport efficiency, type of mass-spectrometer) and software-specific data treatment algorithms. Differences in the upper bound were identified as being due to the non-harmonised application of the upper counting limit. Reporting D99.5 or D99.8 instead of the effectively largest particle diameter (D100) excluded isolated large particles and considerably improved the reproducibility. The particle number-concentration was found to be influenced by small differences in the sample preparation procedure. The comparison of these results with those obtained using electron microscopy showed that the mean and median particle diameter was, in all cases, higher when using spICP-MS. The main reason for this was the higher size detection limit for spICP-MS plus the fact that some of the analysed particles remained agglomerated/aggregated after sonication. Single particle ICP-MS is a powerful screening technique, which in many cases provides sufficient evidence to confirm the need to label a food product as containing (engineered) titanium dioxide nanomaterial according to the current EU regulatory requirements. The overall positive outcome of the method performance evaluation and the current lack of alternative standardised procedures, would indicate this method as being a promising candidate for a full validation study.

VL - 120 M3 - 10.1016/j.foodcont.2020.107550 ER - TY - JOUR T1 - Physicochemical characterization of nanoparticles in food additives in the context of risk identification JF - EFSA Supporting Publications Y1 - 2021 A1 - Eveline Verleysen A1 - Nadia Waegeneers A1 - Sandra De Vos A1 - Frederic Brassinne A1 - Ledecq, Marina A1 - Frederic Van Steen A1 - Mirjana Andjelkovic A1 - Raphael Janssens A1 - Stella Mathioudaki A1 - Lotte Delfosse A1 - Ronny Machiels A1 - Karlien Cheyns A1 - Jan Mast VL - 18 CP - 6 M3 - 10.2903/sp.efsa.2021.EN-6678 ER - TY - JOUR T1 - Agglomeration of titanium dioxide nanoparticles increases toxicological responses in vitro and in vivo JF - Particle and Fibre Toxicology Y1 - 2020 A1 - Sivakumar Murugadoss A1 - Noham Sebaihi A1 - Frederic Brassinne A1 - Jasmine Petry A1 - Stevan M. Cokic A1 - Kirsten L. Van Landuy A1 - Lode Godderis A1 - Jan Mast A1 - Dominique Lison A1 - Peter H. Hoet A1 - Sybille van den Brule KW - Agglomerates KW - Biological responses KW - nanomaterials KW - titanium dioxide KW - toxicity AB -

Background: The terms agglomerates and aggregates are frequently used in the regulatory definition(s) of nanomaterials (NMs) and hence attract attention in view of their potential influence on health effects. However, the influence of nanoparticle (NP) agglomeration and aggregation on toxicity is poorly understood although it is strongly believed that smaller the size of the NPs greater the toxicity. A toxicologically relevant definition of NMs is therefore not yet available, which affects not only the risk assessment process but also hinders the regulation of nano-products. In this study, we assessed the influence of NP agglomeration on their toxicity/biological responses in vitro and in vivo. Results: We tested two TiO2 NPs with different primary sizes (17 and 117 nm) and prepared ad-hoc suspensions composed of small or large agglomerates with similar dispersion medium composition. For in vitro testing, human bronchial epithelial (HBE), colon epithelial (Caco2) and monocytic (THP-1) cell lines were exposed to these suspensions for 24 h and endpoints such as cytotoxicity, total glutathione, epithelial barrier integrity, inflammatory mediators and DNA damage were measured. Large agglomerates of 17 nm TiO2 induced stronger responses than small agglomerates for glutathione depletion, IL-8 and IL-1β increase, and DNA damage in THP-1, while no effect of agglomeration was observed with 117 nm TiO2. In vivo, C57BL/6JRj mice were exposed via oropharyngeal aspiration or oral gavage to TiO2 suspensions and, after 3 days, biological parameters including cytotoxicity, inflammatory cell recruitment, DNA damage and biopersistence were measured. Mainly, we observed that large agglomerates of 117 nm TiO2 induced higher pulmonary responses in aspirated mice and blood DNA damage in gavaged mice compared to small agglomerates. Conclusion: Agglomeration of TiO2 NPs influences their toxicity/biological responses and, large agglomerates do not appear less active than small agglomerates. This study provides a deeper insight on the toxicological relevance of NP agglomerates and contributes to the establishment of a toxicologically relevant definition for NMs.

ER - TY - JOUR T1 - Is aggregated synthetic amorphous silica toxicologically relevant? JF - Particle and Fibre Toxicology Y1 - 2020 A1 - Sivakumar Murugadoss A1 - van den Brûle, Sybille A1 - Frederic Brassinne A1 - Sebaihi, Noham A1 - Jorge Mejia A1 - Stéphane Lucas A1 - Jasmine Petry A1 - Godderis, Lode A1 - Jan Mast A1 - Lison, Dominique A1 - Hoet, Peter H. KW - Aggregates KW - Biological activity KW - In vitro toxicity KW - nanomaterials KW - synthetic amorphous silica AB -

Background:

The regulatory definition(s) of nanomaterials (NMs) frequently uses the term ‘agglomerates and aggregates’ (AA) despite the paucity of evidence that AA are significantly relevant from a nanotoxicological perspective.This knowledge gap greatly afects the safety assessment and regulation of NMs, such as synthetic amorphous silica (SAS). SAS is used in a large panel of industrial applications. They are primarily produced as nanosized particles (1–100 nm in diameter) and considered safe as they form large aggregates (> 100 nm) during the production process. So far, it is indeed believed that large aggregates represent a weaker hazard compared to their nano counterpart. Thus, we assessed the impact of SAS aggregation on in vitro cytotoxicity/biological activity to address the toxicological relevance of aggregates of different sizes.


Results:

We used a precipitated SAS dispersed by different methods, generating 4 ad-hoc suspensions with different aggregate size distributions. Their effect on cell metabolic activity, cell viability, epithelial barrier integrity, total glutathione content and, IL-8 and IL-6 secretion were investigated after 24 h exposure in human bronchial epithelial (HBE), colon epithelial (Caco2) and monocytic cells (THP-1). We observed that the de-aggregated suspension (DE-AGGR), predominantly composed of nano-sized aggregates, induced stronger effects in all the cell lines than the aggregated suspension (AGGR). We then compared DE-AGGR with 2 suspensions fractionated from AGGR: the precipitated fraction (PREC) and the supernatant fraction (SuperN). Very large aggregates in PREC were found to be the least cytotoxic/biologically active compared to other suspensions. SuperN, which contains aggregates larger in size (> 100 nm) than in DE-AGGR but smaller than PREC, exhibited similar activity as DE-AGGR.

Conclusion:

Overall, aggregation resulted in reduced toxicological activity of SAS. However, when comparing aggregates of different sizes, it appeared that aggregates > 100 nm were not necessarily less cytotoxic than their nano-sized counterparts. This study suggests that aggregates of SAS are toxicologically relevant for the definition of NMs.

VL - 17 CP - 1 M3 - 10.1186/s12989-019-0331-3 ER - TY - JOUR T1 - Physicochemical Characterization of the Pristine E171 Food Additive by Standardized and Validated Methods. JF - Nanomaterials (Basel) Y1 - 2020 A1 - Eveline Verleysen A1 - Nadia Waegeneers A1 - Frederic Brassinne A1 - Sandra De Vos A1 - Isaac Ojea Jimenez A1 - Stella Mathioudaki A1 - Jan Mast KW - E171 KW - food additive KW - Single particle ICP-MS KW - transmission electron microscopy AB -

E171 (titanium dioxide) is a food additive that has been authorized for use as a food colorant in the European Union. The application of E171 in food has become an issue of debate, since there are indications that it may alter the intestinal barrier. This work applied standardized and validated methodologies to characterize representative samples of 15 pristine E171 materials based on transmission electron microscopy (TEM) and single-particle inductively coupled plasma mass spectrometry (spICP-MS). The evaluation of selected sample preparation protocols allowed identifying and optimizing the critical factors that determine the measurement of the particle size distribution by TEM. By combining optimized sample preparation with method validation, a significant variation in the particle size and shape distributions, the crystallographic structure (rutile versus anatase), and the physicochemical form (pearlescent pigments versus anatase and rutile E171) was demonstrated among the representative samples. These results are important for risk assessment of the E171 food additive and can contribute to the implementation of the European Food Safety Authority (EFSA) guidance on risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain.

VL - 10 CP - 3 M3 - 10.3390/nano10030592 ER - TY - RPRT T1 - BR/154/A4 To²DeNano Towards a toxicologically relevant definition of nanomaterials final report Y1 - 2019 A1 - Peter Hoet A1 - Godderis, Lode A1 - Sivakumar Murugadoss A1 - Jan Mast A1 - Frederic Brassinne A1 - Lison, Dominique A1 - van den Brûle, Sybille A1 - Jasmine Petry A1 - Sebaihi, Noham KW - aggregation/agglomeration KW - EU definition KW - exposure KW - hazard KW - nanomaterials ER - TY - Generic T1 - Optimization and validation of quantitative TEM analysis of pristine titanium dioxide powders in a regulatory context Y1 - 2019 A1 - Frederic Brassinne A1 - Sandra De Vos A1 - Eveline Verleysen A1 - M. Ledecq A1 - Jan Mast JF - IMEKOFOODS 4 ER - TY - Generic T1 - Our new analytical electron microscope is way better than our conventional one Y1 - 2019 A1 - Frederic Brassinne A1 - Sandra De Vos A1 - Eveline Verleysen A1 - Daisy Tysmans A1 - Jan Mast JF - Inauguration Talos analytical electron microscope CP - Sciensano - Trace Elements and nanomaterials ER - TY - Generic T1 - Physicochemical characterisation of several types of the E171 food additive Y1 - 2019 A1 - Eveline Verleysen A1 - M. Ledecq A1 - Sandra De Vos A1 - I. Ojea Jimenez A1 - Frederic Brassinne A1 - Nadia Waegeneers A1 - Jan Mast KW - Characterization KW - E171 KW - electron microscopy KW - particle size distributions. KW - single particle inductively coupled plasma mass spectroscopy KW - titanium oxide AB -

The application of E171 (titanium dioxide) as a food additive has been an issue of debate in the European Union. A detailed physicochemical characterization of the E171 particles can objectify the discussions and is essential in the context of risk analysis.
This work focuses on the physicochemical characterization of 15 pristine E171 materials by transmission electron microscopy (TEM) and single particle inductively coupled plasma mass spectroscopy (sp-ICP-MS) following CEN/TC 352 guidelines. The E171 samples were purchased on the Belgian market or were obtained from European producers.
In optimized conditions, representative TEM micrographs could be recorded and the ParticleSizer image analysis software succeeded in applying noise reduction and background subtraction, allowing robust automatic thresholding and constituent particle detection. The large majority of constituent particles, confirmed to be TiO2 by energy dispersive X-ray spectroscopy (EDX), were reliably detected and measured by the software. The measurement uncertainty budgets of particle sizing by TEM and sp-ICP-MS are in the order of 10% and 16 % (Ucx, k=2), respectively, based on validation studies of a series of representative test materials. The phase of the E171 particles was determined by powder electron diffraction.
Several types of TiO2 particles were found in pristine E171. These types were shown to be applied as well in food products containing E171. All examined E171 food additives contained a significant amount of nanoparticles. In the most dispersed state, the particle size measurements by TEM and sp-ICP-MS agreed well. Eleven E171 materials consisted of anatase. Three materials consisted of smaller rutile TiO2 particles (20-40 nm) coated on mica. One material contained a mixture of anatase and rutile particles.
In future research, the methodology will be implemented in a systematic and larger scale study of E171 food additives and food items containing E171, available on the market.

JF - IMEKOFOODS 4 UR - https://www.imekofoods4.be/ ER - TY - Generic T1 - Physicochemical Characterisation of the E171 Food Additive Y1 - 2019 A1 - Eveline Verleysen A1 - Marina Ledecq A1 - Sandra De Vos A1 - Isaac Ojea Jimenez A1 - Nadia Waegeneers A1 - Frederic Brassinne A1 - Jan Mast KW - E171 KW - particle size distribution KW - Single particle ICP-MS KW - titanium dioxide KW - transmission electron microscopy AB -

The application of E171 (titanium dioxide) as a food additive has been an issue of debate in the European Union. A detailed physicochemical characterization of the E171 particles can objectify the discussions and is essential in the context of risk analysis. This work focuses on the physicochemical characterization of 15 pristine E171 materials by transmission electron microscopy (TEM) and single particle inductively coupled plasma mass spectroscopy (sp-ICP-MS) following CEN/TC 352 guidelines. The E171 samples were purchased on the Belgian market or were obtained from European producers. To measure the minimal external dimension of the constituent particles of E171, sample preparation protocols influencing particle dispersion (pH, probe sonication and centrifugation) were tested and optimized. In optimized conditions, representative TEM micrographs could be recorded, and it was demonstrated that all examined E171 food additives contained a significant amount of nanoparticles. The large majority of constituent particles, confirmed to be TiO2 by energy dispersive X-ray spectroscopy (EDX), were reliably detected and measured using the ParticleSizer software. In the most dispersed state, the particle size measurements by TEM and sp-ICP-MS agreed well. The measurement uncertainty budgets of particle sizing by TEM and sp-ICP-MS are in the order of 10% and 16 % (Ucx, k=2), respectively, based on validation studies of a series of representative test materials. Electron diffraction demonstrated that both anatase and rutile TiO2 particles were found in pristine E171. Eleven E171 materials consisted of anatase. Three materials consisted of smaller rutile TiO2 particles (20-40 nm) coated on mica. One material contained a mixture of anatase and rutile particles. In future research, the methodology will be implemented in a systematic and larger scale study of E171 food additives and food items containing E171, available on the market.

JF - Recent Advances in Food Analysis (RAFA) PB - University of Chemistry and Technology, Prague, Czech Republic CY - Prague, Czech Republic SN - 978-80-7592-055-3 UR - http://www.rafa2019.eu/pdf/RAFA2019_BoA_web.pdf ER - TY - Generic T1 - Possible solutions to analytical challenges Y1 - 2019 A1 - Frederic Brassinne A1 - Eveline Verleysen A1 - Jan Mast KW - Nanoparticles JF - Workshop: Physicochemical characterisation of nano-sized particles in food ER - TY - RPRT T1 - RF 16/6306 Implementation and validation of an analytical methodology to assess engineered nanomaterials in food additives Nanofood@ Y1 - 2019 A1 - Eveline Verleysen A1 - Sandra De Vos A1 - Nadia Waegeneers A1 - Frederic Brassinne A1 - Stella Mathioudaki A1 - Marina Ledecq A1 - Lotte Delfosse A1 - Jan Mast ER - TY - Generic T1 - Syllabus of the workshop physicochemical characterization of nano-sized particles in food Y1 - 2019 A1 - Eveline Verleysen A1 - Ralf Kaegi A1 - Nadia Waegeneers A1 - Stella Mathioudaki A1 - Frederic Brassinne A1 - Jan Mast KW - Nanoparticles KW - physico-chemical characterization KW - transmission electron microscopy AB -

Scope of this workshop

ER - TY - Generic T1 - Characterization of the TiO2 E171 food additive Y1 - 2018 A1 - Frederic Brassinne A1 - Sandra De Vos A1 - Eveline Verleysen A1 - Pieter-Jan De Temmerman A1 - M. Ledecq A1 - Jan Mast JF - Toxicology Letters VL - 295 M3 - 10.1016/j.toxlet.2018.06.909 ER - TY - Generic T1 - Influence of dispersion method on silica nanoparticle size distribution/aggregation and their chronic toxicity in-vitro Y1 - 2017 A1 - Sivakumar Murugadoss A1 - van den Brûle, Sybille A1 - Sebaihi, Noham A1 - Frederic Brassinne A1 - Jan Mast A1 - Godderis, Lode A1 - Lison, Dominique A1 - Hoet, Peter H. ER - TY - JOUR T1 - Toxicity and biological responses (in vitro) influenced by aggregation and agglomeration of manufactured nanomaterials JF - Toxicology Letters Y1 - 2017 A1 - Sivakumar Murugadoss A1 - van den Brûle, Sybille A1 - Sebaihi, Noham A1 - Frederic Brassinne A1 - Jan Mast A1 - Godderis, Lode A1 - Lison, Dominique A1 - Peter Hoet VL - 280 M3 - 10.1016/j.toxlet.2017.07.535 ER - TY - JOUR T1 - Toxicology of silica nanoparticles: an update JF - Archives of Toxicology Y1 - 2017 A1 - Sivakumar Murugadoss A1 - Lison, Dominique A1 - Godderis, Lode A1 - van den Brûle, Sybille A1 - Jan Mast A1 - Frederic Brassinne A1 - Sebaihi, Noham A1 - Hoet, Peter H. KW - Amorphous silica nanoparticles KW - Oxidative Stress KW - Pyrogenic KW - Stöber KW - toxicity AB -

Large-scale production and use of amorphous silica nanoparticles (SiNPs) have increased the risk of human exposure to SiNPs, while their health effects remain unclear. In this review, scientific papers from 2010 to 2016 were systematically selected and sorted based on in vitro and in vivo studies: to provide an update on SiNPs toxicity and to address the knowledge gaps indicated in the review of Napierska (Part Fibre Toxicol 7:39, 2010). Toxicity of SiNPs in vitro is size, dose, and cell type dependent. SiNPs synthesized by wet route exhibited noticeably different biological effects compared to thermal route-based SiNPs. Amorphous SiNPs (particularly colloidal and stöber) induced toxicity via mechanisms similar to crystalline silica. In vivo, route of administration and physico-chemical properties of SiNPs influences the toxicokinetics. Adverse effects were mainly observed in acutely exposed animals, while no significant signs of toxicity were noted in chronically dosed animals. The correlation between in vitro and in vivo toxicity remains less well established mainly due to improper-unrealistic-dosing both in vitro and in vivo. In conclusion, notwithstanding the multiple studies published in recent years, unambiguous linking of physico-chemical properties of SiNPs types to toxicity, bioavailability, or human health effects is not yet possible.

VL - 91 M3 - 10.1007/s00204-017-1993-y ER - TY - Generic T1 - Characterization of the TiO2 E171 food additive Y1 - 0 A1 - Frederic Brassinne A1 - Jan Mast ED - Sandra De Vos ED - Eveline Verleysen ED - Pieter-Jan De Temmerman ED - Ledecq, Marina AB -

E171 (Titanium dioxide) is an EC approved food additive (EC 1129/2011), authorized to be used as color in foodstuffs. It is widely used for its refractive properties (shiny coating, UV protection) in the food and pharmaceutical industries. It is intended and assumed to be present in bulk form. A nanofraction may be present.Dispersion is crucial step to characterize the particle properties of food additives as it allows to separate the primary particles. To better characterize titanium dioxide food additives (E171) their dispersion method was optimized.

A dispersion methodology based on the Guiot and Spalla approach was applied. It electrosterically stabilizes the (nano)materials, dispersed by sonication, using BSA at a pH determined by zeta potential measurement. Dispersion efficiency was examined by descriptive TEM and using a combination of TEM imaging and image analysis. The latter approach allows to assess the distribution of the particle properties (size, shape, surface structure) quantitatively. For both the pristine TiO2 food additive E171 and the JRC TiO2 representative test material zeta-potential measurement allowed to identify the conditions (pH) where a stable dispersion with a minimal level of agglomeration was observed. The stability of the dispersion was confirmed by descriptive TEM: preparing dispersions of TiO2 through a pH adjustment provides a stable dispersion of single primary particles and small aggregates and agglomerates.

Under the optimized conditions, the minimal external dimension of the primary particles could be measured more precisely and accurately by a combination of EM imaging and image analysis than in metastable conditions, such that the materials could be better classified according to the EC definition of a nanomaterial.

ER -