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The volume-specific surface area, VSSA, is a property of powder materials that is related to particle size and morphology and therefore can have a fundamental influence on the characteristics and performance of materials. VSSA may be used to identify nanomaterials, provides relevant information in the context of their safety assessment, and is a required nanomaterial characterizer for the EU Chemicals Regulation REACH. This chapter introduces the concept of VSSA and the method by Brunauer, Emmett, and Teller (BET method), which is usually applied to measure it. The discussion focusses on the relationship between particle size, shape, and the VSSA, followed by an overview of instrumentation, experimental methods, and standards.

A feasibility study regarding the production of radioactive carbon black and nanotubes has been performed by proton beam irradiation. Experimental and theoretical excitation functions of the nuclear reaction (nat)C(p,x)(7)Be in the proton energy range 24-38 MeV are reported, with an acceptable agreement. We have demonstrated that sufficient activities of (7)Be radioisotope can be produced in carbon black and nanotube that would facilitate studies of their possible impact on human and environment.

The biokinetics of a size-selected fraction (70 nm median size) of commercially available and 48V-radiolabeled [48V]TiO2 nanoparticles has been investigated in female Wistar-Kyoto rats at retention timepoints 1 h, 4 h, 24 h and 7 days after oral application of a single dose of an aqueous [48V]TiO2-nanoparticle suspension by intra-esophageal instillation. A completely balanced quantitative body clearance and biokinetics in all organs and tissues was obtained by applying typical [48V]TiO2-nanoparticle doses in the range of 30–80 μg•kg−1 bodyweight, making use of the high sensitivity of the radiotracer technique. The [48V]TiO2-nanoparticle content was corrected for nanoparticles in the residual blood retained in organs and tissue after exsanguination and for 48V-ions not bound to TiO2-nanoparticles. Beyond predominant fecal excretion about 0.6% of the administered dose passed the gastro-intestinal-barrier after one hour and about 0.05% were still distributed in the body after 7 days, with quantifiable [48V]TiO2-nanoparticle organ concentrations present in liver (0.09 ng•g−1), lungs (0.10 ng•g−1), kidneys (0.29 ng•g−1), brain (0.36 ng•g−1), spleen (0.45 ng•g−1), uterus (0.55 ng•g−1) and skeleton (0.98 ng•g−1). Since chronic, oral uptake of TiO2 particles (including a nano-fraction) by consumers has continuously increased in the past decades, the possibility of chronic accumulation of such biopersistent nanoparticles in secondary organs and the skeleton raises questions about the responsiveness of their defense capacities, and whether these could be leading to adverse health effects in the population at large. After normalizing the fractions of retained [48V]TiO2-nanoparticles to the fraction that passed the gastro-intestinal-barrier and reached systemic circulation, the biokinetics was compared to the biokinetics determined after IV-injection (Part 1). Since the biokinetics patterns differ largely, IV-injection is not an adequate surrogate for assessing the biokinetics after oral exposure to TiO2 nanoparticles.

Submicrometer TiO2 particles, including nanoparticulate fractions, are used in an increasing variety of consumer products, as food additives and also drug delivery applications are envisaged. Beyond exposure of occupational groups, this entails an exposure risk to the public. However, nanoparticle translocation from the organ of intake and potential accumulation in secondary organs are poorly understood and in many investigations excessive doses are applied. The present study investigates the biokinetics and clearance of a low single dose (typically 40–400 μg/kg BW) of 48V-radiolabeled, pure TiO2 anatase nanoparticles ([48V]TiO2NP) with a median aggregate/agglomerate size of 70 nm in aqueous suspension after intravenous (IV) injection into female Wistar rats. Biokinetics and clearance were followed from one-hour to 4-weeks. The use of radiolabeled nanoparticles allowed a quantitative [48V]TiO2NP balancing of all organs, tissues, carcass and excretions of each rat without having to account for chemical background levels possibly caused by dietary or environmental titanium exposure. Highest [48V]TiO2NP accumulations were found in liver (95.5%ID after one day), followed by spleen (2.5%), carcass (1%), skeleton (0.7%) and blood (0.4%). Detectable nanoparticle levels were found in all other organs. The [48V]TiO2NP content in blood decreased rapidly after 24 h while the distribution in other organs and tissues remained rather constant until day-28. The present biokinetics study is part 1 of a series of studies comparing biokinetics after three classical routes of intake (IV injection (part 1), ingestion (part 2), intratracheal instillation (part 3)) under identical laboratory conditions, in order to test the common hypothesis that IV-injection is a suitable predictor for the biokinetics fate of nanoparticles administered by different routes. This hypothesis is disproved by this series of studies.

The biokinetics of a size-selected fraction (70 nm median size) of commercially available and 48V-radiolabeled [48V]TiO2 nanoparticles has been investigated in healthy adult female Wistar-Kyoto rats at retention time-points of 1 h, 4 h, 24 h, 7 d and 28 d after intratracheal instillation of a single dose of an aqueous [48V]TiO2-nanoparticle suspension. A completely balanced quantitative biodistribution in all organs and tissues was obtained by applying typical [48V]TiO2-nanoparticle doses in the range of 40–240 μg·kg−1 bodyweight and making use of the high sensitivity of the radiotracer technique. The [48V]TiO2-nanoparticle content was corrected for residual blood retained in organs and tissues after exsanguination and for 48V-ions not bound to TiO2-nanoparticles. About 4% of the initial peripheral lung dose passed through the air-blood-barrier after 1 h and were retained mainly in the carcass (4%); 0.3% after 28 d. Highest organ fractions of [48V]TiO2-nanoparticles present in liver and kidneys remained constant (0.03%). [48V]TiO2-nanoparticles which entered across the gut epithelium following fast and long-term clearance from the lungs via larynx increased from 5 to 20% of all translocated/absorbed [48V]TiO2-nanoparticles. This contribution may account for 1/5 of the nanoparticle retention in some organs. After normalizing the fractions of retained [48V]TiO2-nanoparticles to the fraction that reached systemic circulation, the biodistribution was compared with the biodistributions determined after IV-injection (Part 1) and gavage (GAV) (Part 2). The biokinetics patterns after IT-instillation and GAV were similar but both were distinctly different from the pattern after intravenous injection disproving the latter to be a suitable surrogate of the former applications. Considering that chronic occupational inhalation of relatively biopersistent TiO2-particles (including nanoparticles) and accumulation in secondary organs may pose long-term health risks, this issue should be scrutinized more comprehensively.

In November 2015, an article by A. J. Lecloux was published in this journal (J Nanopart Res, 17:447, 2015). The article focused on the use of volume-specific surface area (VSSA) for the implementation of the European Commission's recommended definition of "nanomaterial". In that paper, VSSA values were calculated for polydisperse particulate materials using a particle number-based averaging method which do not agree with earlier results of VSSA simulations of polydisperse materials reported in 2014 by the Joint Research Centre (JRC) of the European Commission (EC). In this contribution, we explain the difference between traditional view of VSSA which was used by the JRC and the proposed model of Lecloux. Through the use of some simple examples for polydisperse materials, it is demonstrated that the latter produces values which neither correspond to the generally accepted definition of VSSA nor relate to the commonly used experimental methods for determining VSSA using gas adsorption. Lecloux's model therefore does not constitute a basis for practical implementation of the EC's definition of nanomaterial using gas adsorption techniques.

In this paper the low temperature deposition of nanocrystalline and ultrananocrystalline diamond (UNCD) films is compared and discussed. NCD films were prepared by hot filament chemical vapor deposition from a 1% CH4/H2 mixture, while microwave plasma chemical vapour deposition was used to deposit UNCD films from a mixture of 17% CH4/N2. The resulting films have been thoroughly characterized concerning their morphology and structure by scanning electron microscopy and concerning their crystalline properties by X-ray diffraction. The composition was analyzed by X-ray photoelectron spectroscopy (XPS), whereas XPS and Raman spectroscopy were applied to get information on the bonding structure of the films. The most important result of this study is that the composition, structure, morphology, and bonding environment of UNCD hardly change if the deposition temperature is lowered from 770 to 530 °C or even 450 °C. In contrast, there are drastic changes of the nature of NCD films if the temperature is reduced to 700 °C or even lower. Interestingly, the sp2/sp3 ratio of the NCD films remains low and constant in the temperature range investigated. Rather, the nature of the sp2 grain boundary material undergoes drastic changes if the temperature is lowered below 700 °C. In addition, the films become inhomogeneous on a micrometer (not nanometer) scale. Possible reasons for these observations will be discussed throughout the paper.

Magnetite nanoparticles (Fe3O4 NPs) are manufactured nanomaterials increasingly used in healthcare for different medical applications ranging from diagnosis to therapy. This study deals with the irradiation of Fe3O4 NPs with a proton beam in order to produce 56Co as radiolabel and also with the possible use of nuclear techniques for the quantification of Fe3O4 NPs in biological systems. Particular attention has been focused on the size distribution (in the range of 100 nm) and the surface charge of the NPs characterizing them before and after the irradiation process in order to verify if these essential properties would be preserved during irradiation. Moreover, X-ray diffraction studies have been performed on radioactive and non-radioactive NPs, to assess if major changes in NPs structure might occur due to thermal and/or radiation effects. The radiation emitted from the radiolabels has been used to quantify the cellular uptake of the NPs in in vitro studies. As for the biological applications two cell lines have been selected: immortalized mouse fibroblast cell line (Balb/3T3) and human epithelial colorectal adenocarcinoma cell line (Caco-2). The cell uptake has been quantified by radioactivity measurements of the 56Co radioisotope performed with high resolution γ-ray spectrometry equipment. This study has showed that, under well-established irradiation conditions, Fe3O4 NPs do not undergo significant structural modifications and thus the obtained results are in line with the uptake studies carried out with the same non-radioactive nanomaterials (NMs). Therefore, the radiolabelling method can be fruitfully applied to uptake studies because of the low-level exposure where higher sensitivity is required.

The intensive use of nano sized titanium dioxide (TiO2) particles in many different applications necessitates studies on their risk assessment as there are still open questions on their safe handling and utilization. For reliable risk assessment the interaction of TiO2 nanoparticles (NP) with biological systems ideally needs to be investigated using physico chemically uniform and well characterized NP. In this article we describe the reproducible production of TiO2 NP aerosols using spark ignition technology. Because currently no data are available on inhaled NP in the 10–50 nm diameter range the emphasiswas to generate NP as small as 20 nm for inhalation studies in rodents. For anticipated in vivo dosimetry analyses TiO2 NP were radio labeled with 48V by proton irradiation of the titanium electrodes of the spark generator. The dissolution rate of the 48V label was about 1 within the first day. The highly concentrated polydisperse TiO2 NP aerosol (3–6 x 106 cm 3) proved to be constant over several hours in terms of its count median mobility diameter its geometric standard deviation and number concentration. Extensive characterization of NP chemical composition physical structure morphology and specific surface area was performed. The originally generated amorphous TiO2 NP were converted into crystalline anatase TiO2 NP by thermal annealing at 950 degree Celsius. Both crystalline and amorphous 20 nm TiO2 NP were chain agglomerated/aggregated consisting of primary particles in the range of 5 nm. Disintegration of the deposited TiO2 NP in lung tissue was not detectable within 24 h.

Detection and quantification of engineered nanoparticles (NPs) in complex environmental or biological media is a major challenge since NP concentrations are generally expected to be low compared to elemental background levels. This study presents three different options for radiolabeling of commercial titania NP (TiO2-NP, AEROXIDE® P25, Evonik Industries, mean diameter 21 nm) for particle detection, localization, and tracing under various experimental conditions. The radiolabeling procedures ensure stability and consistency of important particle properties such as size and morphology. With the presented radiolabeling methods, detection (and quantification) limits for TiO2-NPs in concentrations as low as 0.5 ng/L can be realized in complex systems without the necessity of intense sample purification or pretreatment.

A novel, simple DC-DC concept for low-power applications is presented. We propose a predictive peak-current mode controller in discontinuous conduction mode (DCM). The design is able to operate with a minimized output capacitor of only 27nF. Measurements shows low ripple voltage even at maximum load current steps and excellent transient response at a good DC control of Vout.

A method for synthesis of radiolabelled silver nanoparticles is reported. The method is based on proton activation of silver metal powder, enriched in 107Ag, with a 30.7 MeV proton beam. At this proton energy 105gAg is efficiently created, mainly via the 107Ag(p,3n)105Cd → 105gAg reaction. 105gAg has a half-life of 41.29 days and emits easily detectable gamma radiation on decay to 105Pd. This makes it very useful as a tracing radionuclide for experiments over several weeks or months. Following activation and a period to allow short-lived radionuclides to decay, the powder was dissolved in concentrated nitric acid in order to form silver nitrate (AgNO3), which was used to synthesise radiolabelled silver nanoparticles via the process of sodium borohydride reduction. For comparison, non-radioactive silver nanoparticles were synthesised using commercially supplied AgNO3 in order to check if the use of irradiated Ag powder as a starting material would alter in any way the final nanoparticle characteristics. Both nanoparticle types were characterised using dynamic light scattering, zeta-potential and X-ray diffraction measurements, while additionally the non-radioactive samples were analysed by transmission electron microscopy and UV–Vis spectrometry. A hydrodynamic diameter of about 16 nm was determined for both radiolabelled and non-radioactive nanoparticles, while the electron microscopy on the non-radioactive samples indicated that the physical size of the metal NPs was (7.3 ± 1.4) nm., This study has been partially supported by the European Commission’s 7th Framework Programme project QualityNano under the contract agreement SP4-CAPACITIES- 2010-262163.

Owing to their small size and large surface area, nanoparticles (NPs) have physicochemical properties that differ from bulk materials or larger mesh powders. As a result, they have a broad range of actual and potential applications; NPs are widely utilized as catalysts [1], pigments [2] and food additives [3], in the construction [4] or semiconductor [5] industries, in cosmetics and sunscreens [6], and in many other industrial and societal sectors. In addition, by appropriate surface modification NPs can become stable in water and biocompatible, and they can be functionalized with bioactive tags that facilitate selective or preferential interaction with specific receptors or transporters, and, therefore, can be used for targeted drug delivery [7]. The increased incorporation of NPs in everyday products has raised many concerns related to potential toxicological effects derived from long-term workplace, environmental or consumer exposure [8]. On the other hand, the potential applications of NPs in the biomedical field require a reliable and convenient strategy for their pharmacological evaluation. In both scenarios, a method to quantitatively track the NPs after incorporation or administration into living organisms is highly desirable. In this context, labeling NPs with positronor g-emitters may constitute an ideally suited technique to track NPs in vivo using nuclear imaging techniques, such as PET or single photon emission computerized tomography. Attractively, these imaging modalities are considered as minimally invasive (only the administration of the labeled species is required), and allow time-resolved and quantitative determination of the amount of labeled species within the organism. In addition, due to the high penetration capacity of g-rays, they can be easily translated from small experimental animals to humans without significant

The intensive use of nano sized particles in many different applications necessitates studies on their risk assessment as there are still open questions on their safe handling and utilization. For reliable risk assessment the interaction of nanoparticles (NP) with biological systems after various routes of exposure needs to be investigated using well characterized NP. We report here on the generation of gold NP (Au NP) aerosols for inhalation studies with the spark ignition technique and their characterization in terms of chemical composition physical structure morphology and specific surface area and on interaction with lung tissues and lung cells after a 1 h inhalation by mice. The originally generated agglomerated Au NP were converted into compact spherical Au NP by thermal annealing at 600 degrees Celsius providing particles of similar mass but different size and specific surface area. Since there are currently no translocation data available on inhaled Au NP in the 10–50 nm diameter range the emphasis was to generate NP as small as 20 nm for inhalation in rodents. For anticipated in vivo systemic translocation and dosimetry analyses radiolabeled Au NP were created by proton irradiating the gold electrodes of the spark generator thus forming gamma ray emitting 195Au with 186 days half life allowing long term biokinetic studies. The dissolution rate of 195Au from the NP was below detection limits. The highly concentrated polydisperse Au NP Aerosol (1–2 x 107 NP/cm3) proved to be constant over several hours in terms of its count median mobility diameter its geometric standard deviation and number concentration. After collection on filters particles can be re suspended and used for instillation or ingestion studies.

A method for synthesis of radiolabelled amorphous silica nanoparticles is presented. The method is based on the well-known Stober process with the exception that 56Co radiotracer is introduced into one of the precursor materials prior to the initiation of the nanoparticle synthesis. The 56Co was prepared by proton irradiation of an iron foil, followed by dissolution in hydrochloric acid and 56Co/Fe radiochemical separation. In order to determine the residual Fe in the 56Co radiotracer solution, ICP-MS measurements were performed. Nanoparticles in the size range 20–100 nm were synthesised and characterised by gamma spectrometry, ICP-MS, XRD, DLS, and Zeta potential measurement. It was shown that the size and Zeta potential of the nanoparticles was roughly the same following synthesis with or without added 56Co, and in both cases, the structure was that of amorphous silica. It was found that 99.5 % of the 56Co was bound into the nanoparticles during synthesis, and centrifugation experiments confirmed that the radiolabels were stably incorporated into the silica matrix.

Radiolabelled nanoparticles are useful tools for biodistribution or cellular uptake studies related to the risk assessment of nanomaterials. Such studies are ideally carried out with industrially manufactured nanoparticles. Irradiation of small quantities of such nanoparticles, in the form of dry powders, with neutrons or light ions allows radiolabelling while preserving their relevant properties. However dry and loosely packed nanoparticle powders exhibit poor thermal conductivity and may overheat under irradiation. Their effective thermal conductivity is not known and conventional temperature measurement methods are difficult to apply. Reasonably accurate temperature data could be derived from post-irradiation X-ray diffraction studies on anatase TiO2-nanoparticles subjected to proton beams of different intensities. The anatase-to-rutile phase transition starting at about 750◦C was identified by observing rutile peaks in X-ray diffraction patterns. The onset of growth of single diffracting TiO2-domains at around 200◦C was revealed by shape analysis of the diffraction peaks. Identifying these reference temperatures allowed to determine the effective thermal conductivity of the TiO2-nanoparticle powder target and to calibrate the calculated temperature profile. The effective thermal conductivity in the TiO2-NP powder target is close to that of the air trapped in the powder. Thus, the contribution of the nanoparticles to the heat removal from the target is negligible and the obtained temperature profile may be considered as a good estimate for all types of loosely packed nanoparticle powders under light ion irradiation., JRC.I.4-Nanobiosciences

In the framework of the EC funded INBARCA project (Innovative Nanosphere Brachytherapy with Adiabatic Resonance Crossing using Accelerators) a compact, accelerator driven neutron activator has been designed and constructed, with the aim of efficiently utilising ion-beam generated neutrons for the production of radioactive nanoparticles for brachytherapy. The design is based on a modified version of the Adiabatic Resonance Crossing concept, first proposed by C. Rubbia of CERN. The neutron activator has been tested in two experimental configurations, with and without a central lead block. The activation performance on different materials was quantified by γ-spectrometry. Monte Carlo simulations accompanied all experimental runs, and neutron unfolding techniques were used to derive the experimental neutron spectrum. This paper compares the simulated and the unfolded neutron spectra thus obtained, as well as the experimental and simulated activation results for pure Au, Ag, Mo, Ni, Ho and Re foils as well as for Re and Ho nanoparticles. © 2011 IEEE.

Radiolabelling of industrially manufactured nanoparticles is useful for nanoparticle dosimetry in biodistribution or cellular uptake studies for hazard and risk assessment. Ideally for such purposes, any chemical processing post production should be avoided as it may change the physico-chemical characteristics of the industrially manufactured species. In many cases, proton irradiation of nanoparticles allows radiolabelling by transmutation of a tiny fraction of their constituent atoms into radionuclides. However, not all types of nanoparticles offer nuclear reactions leading to radionuclides with adequate radiotracer properties. We describe here a process whereby in such cases nanoparticles can be labelled with 7Be, which exhibits a physical half-life of 53.29 days and emits γ-rays of 478 keV energy, and is suitable for most radiotracer studies. 7Be is produced via the proton-induced nuclear reaction 7Li(p,n)7Be in a fine-grained lithium compound with which the nanoparticles are mixed. The high recoil energy of 7Be atoms gives them a range that allows the 7Be-recoils to be transferred from the lithium compound into the nanoparticles by recoil implantation. The nanoparticles can be recovered from the mixture by dissolving the lithium compound and subsequent filtration or centrifugation. The method has been applied to radiolabel industrially manufactured SiO2 nanoparticles. The process can be controlled in such a way that no alterations of the 7Be-labelled nanoparticles are detectable by dynamic light scattering, X-ray diffraction and electron microscopy. Moreover, cyclotrons with maximum proton energies of 17–18 MeV that are available in most medical research centres could be used for this purpose.