Otmar Geiss - Academia.edu (original) (raw)

Papers by Otmar Geiss

See attached abstractJRC.I.5-Physical and chemical exposure

Elsevier eBooks, 2013

ABSTRACT The addition of a photocatalyst provides decontamination properties to a paints. It is c... more ABSTRACT The addition of a photocatalyst provides decontamination properties to a paints. It is capable of continuosly oxidizing both organic and inorganic pollutants and microorganisms under the influence of light during its lifetime. Photocatalytic paints are useful for degrading air pollutants, reducing the costs of maintenance of the exterior aspect and sterilizing the environment. TiO2 is by far the most widely used photocatalyst, but is only active under UV (e.g. Solar) irradiation, thus limiting its applicability. In this sense, in order to use photocatalytic paints also in indoor environments, new photocatalysts with higher activity under visible irradiation needed. Aspects such as the formation of potentially harmful by-products should also be considered in order to keep the purifying benefits of photocatalytic paints.

Indoor Air, Jan 5, 2011

Car dealer showrooms furnished with desk areas are a work place whose occupants may be exposed to... more Car dealer showrooms furnished with desk areas are a work place whose occupants may be exposed to evaporative emissions from the exhibited cars. The aim of the study was to identify and quantify the main organic compounds present in car dealer showrooms as a result of evaporative emissions from the exhibited cars and to evaluate the personal exposure concentrations of car vendors working in these areas. A total of 19 volatile organic compounds (aromatic compounds, aldehydes and terpenes) were investigated and quantified. Additionally, levels of the same chemicals were measured in the private houses of the car vendors for comparison purposes. All measurements were taken using passive samplers over a consecutive time period of 5 days. Concentrations in the showrooms were on average 12 times higher than the ambient concentration around the showrooms and 10 times higher than the concentrations measured in the private houses of the vendors. Benzene concentrations inside the showrooms ranged from 11 to 93.2 μg/m(3). The personal exposure concentrations of the vendors reached time-weighted levels up to 57.3 μg/m(3) with minimum values around 10 μg/m(3). The results of the study show the significant contributing factor of work place emissions on the vendors' overall exposure load. The high concentrations of some volatile organic compounds (VOCs), including benzene, that were measured in the showrooms highlight the need to safeguard the vendors' health. Measures for reducing personal exposure concentrations could include removing the vendors' desks from the showroom where the cars are exhibited, optimizing the ventilation inside the showrooms and minimizing evaporative emissions from the cars.

International Journal of Nanomedicine

The role of the human immune system in pathologic responses to chemicals including nanomaterials ... more The role of the human immune system in pathologic responses to chemicals including nanomaterials was identified as a gap in current hazard assessments. However, the complexity of the human immune system as well as interspecies variations make the development of predictive toxicity tests challenging. In the present study, we have analysed to what extent fluctuations of the complement system of different individuals will have an impact on the standardisation of immunological tests. Methods: We treated commercially available pooled sera (PS) from healthy males, individual sera from healthy donors and from patients suffering from cancer, immunodeficiency and allergies with small molecules and liposomes. Changes of iC3b protein levels measured in enzyme-linked immunosorbent assays served as biomarker for complement activation. Results: The level of complement activation in PS differed significantly from responses of individual donors (p < 0.01). Only seven out of 32 investigated sera from healthy donors responded similarly to the pooled serum. This variability was even more remarkable when investigating the effect of liposomes on the complement activation in sera from donors with pre-existing pathologies. Neither the 26 sera of donors with allergies nor sera of 16 donors with immunodeficiency responded similar to the PS of healthy donors. Allergy sufferers showed an increase in iC3b levels of 4.16-fold changes when compared to PS treated with liposomes. Discussion: Our studies demonstrate that the use of pooled serum can lead to an over-or underestimation of immunological response in particular for individuals with pre-existing pathologies. This is of high relevance when developing medical products based on nanomaterials and asks for a review of the current practice to use PS from healthy donors for the prediction of immunological effects of drugs in patients. A better understanding of individual toxicological responses to xenobiotics should be an essential part in safety assessments.

Nanomaterials, 2022

In single particle inductively coupled plasma mass spectrometry (spICP-MS), the transport efficie... more In single particle inductively coupled plasma mass spectrometry (spICP-MS), the transport efficiency is fundamental for the correct determination of both particle number concentration and size. In the present study, transport efficiency was systematically determined on three different days with six carefully characterised gold nanoparticle (AuNP) suspensions and in seven European and US expert laboratories using different ICP-MS instruments and spICP-MS software. Both particle size—(TES)—and particle frequency—(TEF)—methods were applied. The resulting transport efficiencies did not deviate much under ideal conditions. The TEF method however systematically resulted in lower transport efficiencies. The extent of this difference (0–300% rel. difference) depended largely on the choice and storage conditions of the nanoparticle suspensions used for the determination. The TES method is recommended when the principal measurement objective is particle size. If the main aim of the measuremen...

The AIRMEX project's aim was to systematically evaluate the relationship between indoor air p... more The AIRMEX project's aim was to systematically evaluate the relationship between indoor air pollution and human (chronic) exposure to pollutants with the focus on public buildings, including indoor environments where children frequently stay like schools and kindergartens, and to evaluate to what extent exposure to these pollutants affected occupants in these areas. The experimental approach consisted in field monitoring campaigns in several European cities in collaboration with local authorities and European institutions. Measuring campaigns were carried out by placing passive samplers in public buildings located in urban areas with high traffic density and in kindergartens/schools mostly situated in suburbs with reduced (medium) traffic impact. Around 1000 samples were taken at 52 public buildings, schools/kindergartens, 142 adults and 25 homes (of the volunteers) and were analysed for VOCs and carbonyl compounds at the JRC laboratories. The characteristics of all the city are...

This publication is a Technical report by the Joint Research Centre (JRC), the European Commissio... more This publication is a Technical report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.

Colloids and Surfaces B: Biointerfaces, 2021

Biocompatible coating based on bovine serum albumin (BSA) was applied on two different TiO2 nanop... more Biocompatible coating based on bovine serum albumin (BSA) was applied on two different TiO2 nanoparticles (aeroxide P25 and food grade E171) to investigate properties and stability of resulting TiO2@BSA composites, under the final perspective to create a "Safe-by-Design" coating, able to uniform, level off and mitigate surface chemistry related phenomena, as naturally occurring when nano-phases come in touch with proteins enriched biological fluids. The first step towards validating the proposed approach is a detailed characterization of surface chemistry with the quantification of amount and stability of BSA coating deposited on nanoparticles' surfaces. At this purpose, we implemented an orthogonal multi-techniques characterization platform, providing important information on colloidal behavior, particle size distribution and BSA-coating structure of investigated TiO2 systems. Specifically, the proposed orthogonal approach enabled the quantitative determination of bound and free (not adsorbed) BSA, a key aspect for the design of intentionally BSA coated nano-structures, in nanomedicine and, overall, for the control of nano-surface reactivity. In fact, the BSA-coating strategy developed and the orthogonal characterisation performed can be extended to different designed nanomaterials in order to further investigate the protein-corona formation and promote the implementation of BSA engineered coating as a strategy to harmonize the surface reactivity and minimize the biological impact.

Journal of Colloid and Interface Science, 2021

Hypothesis: The implementation of the proposal from the European Chemical Agency (ECHA) to restri... more Hypothesis: The implementation of the proposal from the European Chemical Agency (ECHA) to restrict the use of nanoplastics (NP) and microplastics (MP) in consumer products will require reliable methods to perform size and mass-based concentration measurements. Analytical challenges arise at the nanometre to micrometre interface, e.g., 800 nm-10 mm, where techniques applicable at the nanometre scale reach their upper limit of applicability and approaches applicable at the micrometre scale must be pushed to their lower limits of detection.

Food Additives & Contaminants: Part A, 2019

Titanium dioxide is a white colourant authorised as food additive E171 in the EU and is applied i... more Titanium dioxide is a white colourant authorised as food additive E171 in the EU and is applied in a range of food products. Currently the EU specifications for E171 do not refer to the characterisation of particle size distribution; however, this may be requested in the near future. Only a few studies have been published to date reporting data on the size distribution of food grade titanium dioxide. The aim of this study was to characterise the size distribution of titanium dioxide particles contained in eight confectionery products and the pristine titanium dioxide samples used in each of the products. This allowed the direct comparison of the particle size distribution in both the pristine and the extracted materials. By using various analytical techniques, such as transmission electron microscopy, single particle inductively coupled plasma mass spectrometry (sp-ICPMS) and centrifuge liquid sedimentation (CLS) for the characterisation and quantification of the titanium dioxide particle sizes, the impact of the instrumentation on the results was systematically studied. The volume-specific surface area (VSSA) and crystalline structure were also determined for all additives.

Talanta, 2017

Single particle-inductively coupled plasma mass spectrometry (SP-ICPMS) is a promising technique ... more Single particle-inductively coupled plasma mass spectrometry (SP-ICPMS) is a promising technique able to generate the number based-particle size distribution (PSD) of nanoparticles (NPs) in aqueous suspensions. However, SP-ICPMS analysis is not consolidated as routine-technique yet and is not typically applied to real test samples with unknown composition. This work presents a methodology to detect, quantify and characterise the number-based PSD of Ag-NPs in different environmental aqueous samples (drinking and lake waters), aqueous samples derived from migration tests and consumer products using SP-ICPMS. The procedure is built from a pragmatic view and involves the analysis of serial dilutions of the original sample until no variation in the measured size values is observed while keeping particle counts proportional to the dilution applied. After evaluation of the analytical figures of merit, the SP-ICPMS method exhibited excellent linearity (r(2)>0.999) in the range (1-25) × 1...

Journal of Chromatography A, 2016

Home > Multimethod approach for the detection and characterisation of food-grade synthetic amorph... more Home > Multimethod approach for the detection and characterisation of food-grade synthetic amorphous silica nanoparticles

The designations employed and the presentation of the material in this publication do not imply t... more The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. All reasonable precautions have been taken by the World Health Organization to verify the information contained in this publication. However, the published material is being distributed without warranty of any kind, either express or implied. The responsibility for the interpretation and use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use. The views expressed by authors, editors, or expert groups do not necessarily represent the decisions or the stated policy of the World Health Organization.

See attached abstractJRC.I.5-Physical and chemical exposure

Elsevier eBooks, 2013

ABSTRACT The addition of a photocatalyst provides decontamination properties to a paints. It is c... more ABSTRACT The addition of a photocatalyst provides decontamination properties to a paints. It is capable of continuosly oxidizing both organic and inorganic pollutants and microorganisms under the influence of light during its lifetime. Photocatalytic paints are useful for degrading air pollutants, reducing the costs of maintenance of the exterior aspect and sterilizing the environment. TiO2 is by far the most widely used photocatalyst, but is only active under UV (e.g. Solar) irradiation, thus limiting its applicability. In this sense, in order to use photocatalytic paints also in indoor environments, new photocatalysts with higher activity under visible irradiation needed. Aspects such as the formation of potentially harmful by-products should also be considered in order to keep the purifying benefits of photocatalytic paints.

Indoor Air, Jan 5, 2011

Car dealer showrooms furnished with desk areas are a work place whose occupants may be exposed to... more Car dealer showrooms furnished with desk areas are a work place whose occupants may be exposed to evaporative emissions from the exhibited cars. The aim of the study was to identify and quantify the main organic compounds present in car dealer showrooms as a result of evaporative emissions from the exhibited cars and to evaluate the personal exposure concentrations of car vendors working in these areas. A total of 19 volatile organic compounds (aromatic compounds, aldehydes and terpenes) were investigated and quantified. Additionally, levels of the same chemicals were measured in the private houses of the car vendors for comparison purposes. All measurements were taken using passive samplers over a consecutive time period of 5 days. Concentrations in the showrooms were on average 12 times higher than the ambient concentration around the showrooms and 10 times higher than the concentrations measured in the private houses of the vendors. Benzene concentrations inside the showrooms ranged from 11 to 93.2 μg/m(3). The personal exposure concentrations of the vendors reached time-weighted levels up to 57.3 μg/m(3) with minimum values around 10 μg/m(3). The results of the study show the significant contributing factor of work place emissions on the vendors&#39; overall exposure load. The high concentrations of some volatile organic compounds (VOCs), including benzene, that were measured in the showrooms highlight the need to safeguard the vendors&#39; health. Measures for reducing personal exposure concentrations could include removing the vendors&#39; desks from the showroom where the cars are exhibited, optimizing the ventilation inside the showrooms and minimizing evaporative emissions from the cars.

International Journal of Nanomedicine

The role of the human immune system in pathologic responses to chemicals including nanomaterials ... more The role of the human immune system in pathologic responses to chemicals including nanomaterials was identified as a gap in current hazard assessments. However, the complexity of the human immune system as well as interspecies variations make the development of predictive toxicity tests challenging. In the present study, we have analysed to what extent fluctuations of the complement system of different individuals will have an impact on the standardisation of immunological tests. Methods: We treated commercially available pooled sera (PS) from healthy males, individual sera from healthy donors and from patients suffering from cancer, immunodeficiency and allergies with small molecules and liposomes. Changes of iC3b protein levels measured in enzyme-linked immunosorbent assays served as biomarker for complement activation. Results: The level of complement activation in PS differed significantly from responses of individual donors (p < 0.01). Only seven out of 32 investigated sera from healthy donors responded similarly to the pooled serum. This variability was even more remarkable when investigating the effect of liposomes on the complement activation in sera from donors with pre-existing pathologies. Neither the 26 sera of donors with allergies nor sera of 16 donors with immunodeficiency responded similar to the PS of healthy donors. Allergy sufferers showed an increase in iC3b levels of 4.16-fold changes when compared to PS treated with liposomes. Discussion: Our studies demonstrate that the use of pooled serum can lead to an over-or underestimation of immunological response in particular for individuals with pre-existing pathologies. This is of high relevance when developing medical products based on nanomaterials and asks for a review of the current practice to use PS from healthy donors for the prediction of immunological effects of drugs in patients. A better understanding of individual toxicological responses to xenobiotics should be an essential part in safety assessments.

Nanomaterials, 2022

In single particle inductively coupled plasma mass spectrometry (spICP-MS), the transport efficie... more In single particle inductively coupled plasma mass spectrometry (spICP-MS), the transport efficiency is fundamental for the correct determination of both particle number concentration and size. In the present study, transport efficiency was systematically determined on three different days with six carefully characterised gold nanoparticle (AuNP) suspensions and in seven European and US expert laboratories using different ICP-MS instruments and spICP-MS software. Both particle size—(TES)—and particle frequency—(TEF)—methods were applied. The resulting transport efficiencies did not deviate much under ideal conditions. The TEF method however systematically resulted in lower transport efficiencies. The extent of this difference (0–300% rel. difference) depended largely on the choice and storage conditions of the nanoparticle suspensions used for the determination. The TES method is recommended when the principal measurement objective is particle size. If the main aim of the measuremen...

The AIRMEX project's aim was to systematically evaluate the relationship between indoor air p... more The AIRMEX project's aim was to systematically evaluate the relationship between indoor air pollution and human (chronic) exposure to pollutants with the focus on public buildings, including indoor environments where children frequently stay like schools and kindergartens, and to evaluate to what extent exposure to these pollutants affected occupants in these areas. The experimental approach consisted in field monitoring campaigns in several European cities in collaboration with local authorities and European institutions. Measuring campaigns were carried out by placing passive samplers in public buildings located in urban areas with high traffic density and in kindergartens/schools mostly situated in suburbs with reduced (medium) traffic impact. Around 1000 samples were taken at 52 public buildings, schools/kindergartens, 142 adults and 25 homes (of the volunteers) and were analysed for VOCs and carbonyl compounds at the JRC laboratories. The characteristics of all the city are...

This publication is a Technical report by the Joint Research Centre (JRC), the European Commissio... more This publication is a Technical report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.

Colloids and Surfaces B: Biointerfaces, 2021

Biocompatible coating based on bovine serum albumin (BSA) was applied on two different TiO2 nanop... more Biocompatible coating based on bovine serum albumin (BSA) was applied on two different TiO2 nanoparticles (aeroxide P25 and food grade E171) to investigate properties and stability of resulting TiO2@BSA composites, under the final perspective to create a "Safe-by-Design" coating, able to uniform, level off and mitigate surface chemistry related phenomena, as naturally occurring when nano-phases come in touch with proteins enriched biological fluids. The first step towards validating the proposed approach is a detailed characterization of surface chemistry with the quantification of amount and stability of BSA coating deposited on nanoparticles' surfaces. At this purpose, we implemented an orthogonal multi-techniques characterization platform, providing important information on colloidal behavior, particle size distribution and BSA-coating structure of investigated TiO2 systems. Specifically, the proposed orthogonal approach enabled the quantitative determination of bound and free (not adsorbed) BSA, a key aspect for the design of intentionally BSA coated nano-structures, in nanomedicine and, overall, for the control of nano-surface reactivity. In fact, the BSA-coating strategy developed and the orthogonal characterisation performed can be extended to different designed nanomaterials in order to further investigate the protein-corona formation and promote the implementation of BSA engineered coating as a strategy to harmonize the surface reactivity and minimize the biological impact.

Journal of Colloid and Interface Science, 2021

Hypothesis: The implementation of the proposal from the European Chemical Agency (ECHA) to restri... more Hypothesis: The implementation of the proposal from the European Chemical Agency (ECHA) to restrict the use of nanoplastics (NP) and microplastics (MP) in consumer products will require reliable methods to perform size and mass-based concentration measurements. Analytical challenges arise at the nanometre to micrometre interface, e.g., 800 nm-10 mm, where techniques applicable at the nanometre scale reach their upper limit of applicability and approaches applicable at the micrometre scale must be pushed to their lower limits of detection.

Food Additives & Contaminants: Part A, 2019

Titanium dioxide is a white colourant authorised as food additive E171 in the EU and is applied i... more Titanium dioxide is a white colourant authorised as food additive E171 in the EU and is applied in a range of food products. Currently the EU specifications for E171 do not refer to the characterisation of particle size distribution; however, this may be requested in the near future. Only a few studies have been published to date reporting data on the size distribution of food grade titanium dioxide. The aim of this study was to characterise the size distribution of titanium dioxide particles contained in eight confectionery products and the pristine titanium dioxide samples used in each of the products. This allowed the direct comparison of the particle size distribution in both the pristine and the extracted materials. By using various analytical techniques, such as transmission electron microscopy, single particle inductively coupled plasma mass spectrometry (sp-ICPMS) and centrifuge liquid sedimentation (CLS) for the characterisation and quantification of the titanium dioxide particle sizes, the impact of the instrumentation on the results was systematically studied. The volume-specific surface area (VSSA) and crystalline structure were also determined for all additives.

Talanta, 2017

Single particle-inductively coupled plasma mass spectrometry (SP-ICPMS) is a promising technique ... more Single particle-inductively coupled plasma mass spectrometry (SP-ICPMS) is a promising technique able to generate the number based-particle size distribution (PSD) of nanoparticles (NPs) in aqueous suspensions. However, SP-ICPMS analysis is not consolidated as routine-technique yet and is not typically applied to real test samples with unknown composition. This work presents a methodology to detect, quantify and characterise the number-based PSD of Ag-NPs in different environmental aqueous samples (drinking and lake waters), aqueous samples derived from migration tests and consumer products using SP-ICPMS. The procedure is built from a pragmatic view and involves the analysis of serial dilutions of the original sample until no variation in the measured size values is observed while keeping particle counts proportional to the dilution applied. After evaluation of the analytical figures of merit, the SP-ICPMS method exhibited excellent linearity (r(2)>0.999) in the range (1-25) × 1...

Journal of Chromatography A, 2016

Home > Multimethod approach for the detection and characterisation of food-grade synthetic amorph... more Home > Multimethod approach for the detection and characterisation of food-grade synthetic amorphous silica nanoparticles

The designations employed and the presentation of the material in this publication do not imply t... more The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. All reasonable precautions have been taken by the World Health Organization to verify the information contained in this publication. However, the published material is being distributed without warranty of any kind, either express or implied. The responsibility for the interpretation and use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use. The views expressed by authors, editors, or expert groups do not necessarily represent the decisions or the stated policy of the World Health Organization.