Burkhard Stahlmecke

• PhD (Dr. rer. nat.)
• Institut für Energie- und Umwelttechnik

Advanced materials are rapidly being developed in different material categories. They share little commonalities apart from their novelty, which raises concerns that these materials may fall into a regulatory gap...

Background Epidemiological studies have related desert dust events to increased respiratory morbidity and mortality. Although the Sahara is the largest source of desert dust, Saharan dust (SD) has been barely examined in toxicological studies. Here, we aimed to assess the NLRP3 inflammasome-caspase-1-pathway-dependent pro-inflammatory potency of SD...

Epidemiological studies have shown that desert dust exposure affects respiratory health. We aimed to investigate the NLRP3 inflammasome-caspase-1 pathway-dependent inflammatory properties of Saharan dust (SD) in a macrophage model and an air-liquid interface (ALI) co-culture model of the alveolar epithelium. Under submerged conditions wild-type (WT...

High aspect ratio materials (HARMs) like multi-walled carbon nanotubes (MWCNTs) show material properties that enable innovative applications but also raise concerns about harmful effects to humans due to their asbestos-like pathogenicity. The fibre-pathological paradigm was established for asbestos and other HARM, linking fibre-specific adverse eff...

Desert dust is increasingly recognized as a major air pollutant affecting respiratory health. Since desert dust exposure cannot be regulated, the hazardousness of its components must be understood to enable health risk mitigation strategies. Saharan dust (SD) comprises about half of the global desert dust and contains quartz, a toxic mineral dust t...

In vivo toxicokinetic studies provide evidence for the translocation and accumulation of nanoparticles (NP) in the brain, thereby causing concern for adverse health effects, particularly for effects following chronic exposure. To date, only few studies investigated the effects of NP exposure on neuronal function in vitro, primarily focusing on shor...

Cystic fibrosis is an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) that can lead to terminal respiratory failure. Ultrafine carbonaceous particles, which are ubiquitous in ambient urban and indoor air, are increasingly considered as major contributors to the global health burden...

We present the scheme for risk banding of high aspect-ratio materials (HARM). The fibre-pathological paradigm has been long established as a grouping approach for HARM. Material properties could be linked to fibre-specific adverse effects that eventually would lead to the outcomes of fibrosis and mesothelioma. The InnoMat.Life scheme makes use of m...

Background There is an increasing concern about the neurotoxicity of engineered nanomaterials (NMs). To investigate the effects of subchronic oral exposures to SiO 2 and CeO 2 NMs on Alzheimer’s disease (AD)-like pathology, 5xFAD transgenic mice and their C57BL/6J littermates were fed ad libitum for 3 or 14 weeks with control food pellets, or pelle...

Rodent studies on the effects of engineered nanomaterials (ENM) on the gut microbiome have revealed contradictory results. Our aim was to assess the effects of four well-investigated model ENM using a realistic exposure scenario. Two independent ad libitum feeding studies were performed. In study 1, female mice from the local breeding facility rece...

In recent years, concerns have emerged about the potential neurotoxic effects of engineered nanomaterials (NMs). Titanium dioxide and silver are among the most widely used types of metallic NMs. We have investigated the effects of these NMs on behaviour and neuropathology in male and female C57BL/6 J mice following 28-day oral exposure with or with...

With the rising interest in the effects of orally ingested engineered nanomaterials (ENMs), much effort is undertaken to develop and advance intestinal in vitro models. The cytotoxic, proinflammatory, and DNA damaging properties of polyvinylpyrrolidone‐capped silver (Ag‐PVP) and titanium dioxide (TiO2, P25) ENM in four in vitro models of increasing...

The convergence of nanotechnology and biotechnology has led to substantial advancements in nano-biomaterials (NBMs) used in medical devices (MD) and advanced therapy medicinal products (ATMP). However, there are concerns that applications of NBMs for medical diagnostics, therapeutics and regenerative medicine could also pose health and/or environme...

Global production of fibrous material is significantly growing reaching an expected 145 million metric tons in 2030. Fiber production includes mostly synthetic polymers, cotton and man-made cellulose (viscose). The main uses are in clothing, household and furnishing, industrial construction, automotive and other. Increasing consumption of fabric ma...

Nowadays, both micro- and nanomaterials are processed in cement to improve application properties or reduce cement consumption in concrete. The present study deals with the impact of nanostructured SiO 2 , TiO 2 ...

The shredding of waste of electrical and electronic equipment (WEEE) and other products, incorporated with nanomaterials, can lead to a substantial release of nanomaterials. Considering the uncertainty, complexity, and scarcity of experimental data on release, we present the development of a Bayesian belief network (BBN) model. This baseline model...

In the EU, there is an increasing need for regulatory agencies to establish health-based threshold limits for airborne particles. A prerequisite for such projects is the validation and comparison of existing and newly developed particle analyzers. Corresponding proficiency tests have often been conducted with the help of inter-laboratory tests usin...

Conventional methods for total dust sampling from industrial high-temperature aerosols containing condensable species, e.g., in boilers of municipal solid waste incinerators (MSWI), are always influenced by condensation artifacts. Therefore, we extended the scope of a previously developed probe intended for size-fractionated aerosol sampling with r...

Chlorine containing particles in boilers of municipal solid waste incinerators (MSWI) have been under suspicion for a long time to essentially drive corrosion processes. However, at high temperatures all sampling techniques that extract and quench the aerosol are known to be distorted by vapour condensation and particle losses. Therefore, a novel p...

Occupational exposure to nanomaterial aerosols poses potential health risks to workers at nanotechnology workplaces. Understanding the mechanical stability of airborne nanoparticle agglomerates under varied mechanical forces and environmental conditions is important for estimating their emission potential and the released particle size distribution...

A novel probe has been developed to characterize particles in boilers of waste incineration plants, which are under suspicion to essentially drive the corrosion processes. The probe collects larger particles on impaction plates and smaller particles on membranes, whose deposition characteristics have been studied by computational fluid dynamics. Ar...

Nanocomposite materials are ubiquitous in outdoor applications. Product performance is determined by the resilience of the bulk material, but aging induces nanoscale releases already from conventional materials. Thus, aging and wear (or wear and aging) might also release embedded nanomaterials from composites. Here, we challenge the hypothesis of r...

Nationale Umsetzung der künftigen BVT-Schlussfolgerungen für Großfeuerungsanlagen Kurzfassung Mit der für 2017 erwarteten Veröffentlichung von BVT-Schussfolgerungen für Großfeuerungsanlagen seitens der Europäischen Kommission wird eine umfängliche Anpassung der nationalen Vorschriften notwendig. Dies betrifft insbesondere die 13. BImSchV, aber auch...

Different types of aerosolization and deagglomeration testing systems exist for studying the properties of nanomaterial powders and their aerosols. However, results are dependent on the specific methods used. In order to have well-characterized aerosols, we require a better understanding of how system parameters and testing conditions influence the...

Different types of aerosolization and deagglomeration testing systems exist for studying the properties of nanomaterial powders and their aerosols. However, results are dependent on the specific methods used. In order to have well-characterized aerosols, we require a better understanding of how system parameters and testing conditions influence the...

Release of nanomaterials may occur during any stage of the life-cycle and can eventually lead to exposure to humans, the environment or products. Due to the large number of combinations of release processes and nanomaterials, release scenarios can currently only be tested on a case-by-case basis. This chapter presents five case studies on nanomater...

Representative exposure measurement, following dedicated measurement strategies, is one of the foundations for epidemiological studies (Dahmann et al. 2008). Furthermore, each exposure assessment can only be used in an international context if harmonized and accepted measurement strategies are applied. Although accepted protocols are available for...

Number size distributions of airborne particles are relevant to fields including ambient monitoring, pharmaceutical and automotive measurements. A number of commercially available instruments can be used to determine particle number size distributions including the Electrical Low Pressure Impactor (ELPI), Scanning Mobility Particle Sizer (SMPS), Fa...

In the EU there is an increasing need for regulatory agencies to derive health based threshold limits based on human inhalation studies with airborne particles. A necessary prerequisite for such projects is the development of a suitable generator system to produce nanoparticle test aerosols for human whole-body inhalation studies. We decided to use...

An increasing variety of different nanostructured materials including bionanomaterials are used. During synthesis, but also during use of nanostructured materials along their life-cycle, nanostructured materials and engineered nano-objects (ENO) – may be released into the environment. They will follow different exposure pathways and create an expos...

In view of the steadily increasing use of zinc oxide nanoparticles in various industrial and consumer applications, toxicological investigations to evaluate their safety are highly justified. We have investigated mechanisms of ZnO nanoparticle-induced apoptosis and necrosis in macrophages in relation to their important role in the clearance of inha...

A personal sampler that thermophoretically samples particles between a few nanometers and approximately 300 nm has been designed and first prototypes built. The thermal precipitator (TP) is designed to take samples in the breathing zone of a worker in order to determine the personal exposure to airborne nanomaterials. In the sampler, particles are...

The German MAK committee recommended in 2009 a lower threshold limit value for airborne zinc. An adapted human inhalation study was setup to corroborate this recommendation. The technical development and the validation of a suitable flame generator system were realized as a necessary prerequisite for a human inhalation study with zinc oxide (ZnO) i...

The European Commission Joint Research Centre (JRC) provides scientific support to European Union policy regarding nanotechnology and public health in a sustainable environment. Over the last three years, the JRC has focused part of its work on establishing and applying a priority list (NM-Series) of representative manufactured nanomaterials (RMNs)...

A new Thermal Precipitator (TP) was developed as a personal sampler for nanoparticle exposure studies. Two parallel 20-mm-long plates with different but uniform temperatures were introduced into the TP with an appropriate gap distance, to achieve a uniform temperature gradient along the length of the plates. Particles are thermophoretically deposit...

The stability of agglomerates is not only an important material parameter of powders but also of interest for estimating the particle size upon accidental release into the atmosphere. This is especially important when the size of primary particles is well below the agglomerate size, which is usually the case when the size of primary particles is be...

Nanoparticle Surface Area Monitor (NSAM, TSI model 3550 and Aerotrak 9000) is an instrument designed to measure airborne surface area concentrations that would deposit in the alveolar or tracheobronchial region of the lung. It was found that the instrument can only be reliably used for the size range of nanoparticles between 20and 100nm. The upper...

Toxicological testing of nanoparticles is often done in in vitro or in vivo studies by applying suspension onto cells. The dose is the derived from the known particle concentration in the suspension. One important route of nanoparticle uptake is via inhalation. Hence providing well characterized aerosols for toxicological investigations seems to be...

Particle contamination is a major concern in clean manufacturing. We present a model that predicts the diffusional particle contamination probability on inverted surfaces under the influence of gravity and thermophoresis at low pressure level. The model follows an analytical-statistical approach that can be solved using common spreadsheet software;...

Particle contamination is a major concern in clean manufacturing. We present a model that predicts the diffusional particle contamination probability on inverted surfaces under the influence of gravity and thermophoresis at low pressure level, relevant to semiconductor manufacturing using extreme ultraviolet lithography. The model follows an analyt...

In situ electromigration studies on polycrystalline gold nanowires are performed using a high resolution scanning electron microscope. Simultaneously, the resistance of the gold nanowires is recorded during current stressing. The nanowires are prepared by electron beam lithography (EBL) and subsequent thermal evaporation of gold onto the resist mas...

We present in situ scanning electron microscope electromigration measurements on fine-grained gold nanowires. The grain size of 20–40 nm is much smaller than the wire width of . Electrical breakdown occurs in a slit-like manner, which has been observed commonly for bamboo-like or single-crystalline wires. Furthermore, the development of void area i...

We report the fabrication of large area (�5mm2) magnetic dot arrays by electron beam lithography (EBL). After a standard spin on process the PMMA resist mask is exposed in a LEO 1530 scanning electron microscope (SEM) using the advanced SEM/FIB nanolithography System ELPHY plus from Raith. Different exposure modes have been tested to produce dots w...

We studied electromigration in polycrystalline gold and single crystalline silver nanowires. The gold wires are prepared using a two step electron beam lithography process. The silver wires grow self organized and epitaxially along step edges on Si (001) substrates and have a typical width of 200 – 500 nm and a length up to 100 μm. Electromigration...

We present electromigration experiments on single-crystalline silver nanowires. The wires were grown on 4° vicinal silicon (100) substrates by self-organization and were contacted by electron beam lithography. The electromigration experiments were performed in situ in a scanning electron microscope at room temperature with constant dc conditions. I...

The results on thin gold nanowires obtained in situ in a scanning electron microscope (SEM) are presented. The wires were prepared using electron beam lithography with a width around 500 nm and a length of several um. Electromigration tests were carried out at room temperature with a current density above 108 A/cm2. Observation of the nucleation an...

We report the fabrication of large area (∼ 5mm2) magnetic dot arrays by electron beam lithography (EBL). After a standard spin on process the PMMA resist mask is exposed in a LEO 1530 scanning electron microscope (SEM) using the advanced SEM/FIB nanolithography System ELPHY plus from Raith. Different exposure modes have been tested to produce dots...

We have studied the magnetization reversal behavior of Co, Fe, and Py nanowires by Hall magnetometry at 4.2 K. The wires with a width w ranging from 100 nm to 1 μm were fabricated with one end on a Hall cross prepared from a GaAs/AlxGa1−xAs heterostructure, containing a two-dimensional electron system. The magnetization reversal behavior differs si...

A method for the postdeposition organic coating of metallic nanoparticles is introduced. FePt nanoparticles from the gas phase are deposited onto Si substrates which are pre-coated with multilayers of phospholipid molecules by spin coating. If the substrate temperature is just below or above the temperature, at which the phospholipids undergo a pha...

Als Elektromigration bezeichnet man den strominduzierten Massetransport in metallischen Leitern. Sie stellt den Hauptgrund für das Versagen von integrierten Schaltkreisen dar und ist seit mehr als 50 Jahren Gegenstand intensiver Untersuchungen. In dieser Arbeit wurde die Elektromigration in polykristallinen Goldleiterbahnen und einkristallinen, se...