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Mrkwitschka P, Rühle B, Kuchenbecker P, Löhmann O, Lindemann F, Hodoroaba VD. Embedding and cross-sectioning as a sample preparation procedure for accurate and representative size and shape measurement of nanopowders. Sci Rep 2024; 14:511. [PMID: 38177208 PMCID: PMC10766598 DOI: 10.1038/s41598-023-51094-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 12/30/2023] [Indexed: 01/06/2024] Open
Abstract
Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer-Emmet-Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed.
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Affiliation(s)
- Paul Mrkwitschka
- Division 6.1 Surface Analysis and Interfacial Chemistry, Federal Institute for Materials Research and Testing (BAM), 12203, Berlin, Germany.
| | - Bastian Rühle
- Department 1 Analytical Chemistry, Reference Materials, Federal Institute for Materials Research and Testing (BAM), 12203, Berlin, Germany
| | - Petra Kuchenbecker
- Division 5.4 Advanced Multi-materials Processing, Federal Institute for Materials Research and Testing (BAM), 12203, Berlin, Germany
| | - Oliver Löhmann
- Division 4.2 Material-Microbiome Interactions, Federal Institute for Materials Research and Testing (BAM), 12203, Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner Platz 1, 14109, Berlin, Germany
| | - Franziska Lindemann
- Division 5.4 Advanced Multi-materials Processing, Federal Institute for Materials Research and Testing (BAM), 12203, Berlin, Germany
| | - Vasile-Dan Hodoroaba
- Division 6.1 Surface Analysis and Interfacial Chemistry, Federal Institute for Materials Research and Testing (BAM), 12203, Berlin, Germany.
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Automation and Standardization-A Coupled Approach towards Reproducible Sample Preparation Protocols for Nanomaterial Analysis. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030985. [PMID: 35164246 PMCID: PMC8838799 DOI: 10.3390/molecules27030985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 11/16/2022]
Abstract
Whereas the characterization of nanomaterials using different analytical techniques is often highly automated and standardized, the sample preparation that precedes it causes a bottleneck in nanomaterial analysis as it is performed manually. Usually, this pretreatment depends on the skills and experience of the analysts. Furthermore, adequate reporting of the sample preparation is often missing. In this overview, some solutions for techniques widely used in nano-analytics to overcome this problem are discussed. Two examples of sample preparation optimization by automation are presented, which demonstrate that this approach is leading to increased analytical confidence. Our first example is motivated by the need to exclude human bias and focuses on the development of automation in sample introduction. To this end, a robotic system has been developed, which can prepare stable and homogeneous nanomaterial suspensions amenable to a variety of well-established analytical methods, such as dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), field-flow fractionation (FFF) or single-particle inductively coupled mass spectrometry (sp-ICP-MS). Our second example addresses biological samples, such as cells exposed to nanomaterials, which are still challenging for reliable analysis. An air-liquid interface has been developed for the exposure of biological samples to nanomaterial-containing aerosols. The system exposes transmission electron microscopy (TEM) grids under reproducible conditions, whilst also allowing characterization of aerosol composition with mass spectrometry. Such an approach enables correlative measurements combining biological with physicochemical analysis. These case studies demonstrate that standardization and automation of sample preparation setups, combined with appropriate measurement processes and data reduction are crucial steps towards more reliable and reproducible data.
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Kaegi R, Fierz M, Hattendorf B. Quantification of Nanoparticles in Dispersions Using Transmission Electron Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-9. [PMID: 33973509 DOI: 10.1017/s1431927621000398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The quantification of the particle size and the number concentration (PNC) of nanoparticles (NPs) is key for the characterization of nanomaterials. Transmission electron microscopy (TEM) is often considered as the gold standard for assessing the size of NPs; however, the TEM sample preparation suitable for estimating the PNC based on deposited NPs is challenging. Here, we use an ultrasonic nebulizer (USN) to transfer NPs from aqueous suspensions into dried aerosols which are deposited on TEM grids in an electrostatic precipitator of an aerosol monitor. The deposition efficiency of the electrostatic precipitator was ≈2%, and the transport efficiency of the USN was ≈7%. Experiments using SiO2 NPs (50–200 nm) confirmed an even deposition of the nebulized particles in the center of the TEM grids. PNCs of the SiO2 NPs derived from TEM images underestimated the expected PNCs of the suspensions by a factor of up to three, most likely resulting from droplet coagulation and NP aggregation in the USN. Nevertheless, single particles still dominated the PNC. Our approach results in reproducible and even deposition of particles on TEM grids suitable for morphological analysis and allows an estimation of the PNC in the suspensions based on the number of particles detected by TEM.
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Affiliation(s)
- Ralf Kaegi
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600Dübendorf, Switzerland
| | - Martin Fierz
- naneos particle solutions GmbH, Dorfstr. 69, 5210Windisch, Switzerland
| | - Bodo Hattendorf
- Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
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Martín Giménez VM, Russo MG, Narda GE, Fuentes LB, Mazzei L, Gamarra-Luques C, Kassuha DE, Manucha W. Synthesis, physicochemical characterisation and biological activity of anandamide/ɛ-polycaprolactone nanoparticles obtained by electrospraying. IET Nanobiotechnol 2020; 14:86-93. [PMID: 31935683 PMCID: PMC8676047 DOI: 10.1049/iet-nbt.2019.0108] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 10/03/2019] [Accepted: 11/13/2019] [Indexed: 12/16/2022] Open
Abstract
Drug encapsulation in nanocarriers such as polymeric nanoparticles (Nps) may help to overcome the limitations associated with cannabinoids. In this study, the authors' work aimed to highlight the use of electrospraying techniques for the development of carrier Nps of anandamide (AEA), an endocannabinoid with attractive pharmacological effects but underestimated due to its unfavourable physicochemical and pharmacokinetic properties added to its undesirable effects at the level of the central nervous system. The authors characterised physicochemically and evaluated in vitro biological activity of anandamide/ɛ-polycaprolactone nanoparticles (Nps-AEA/PCL) obtained by electrospraying in epithelial cells of the human proximal tubule (HK2), to prove the utility of this method and to validate the biological effect of Nps-AEA/PCL. They obtained particles from 100 to 900 nm of diameter with a predominance of 200-400 nm. Their zeta potential was -20 ± 1.86 mV. They demonstrated the stable encapsulation of AEA in Nps-AEA/PCL, as well as its dose-dependent capacity to induce the expression of iNOS and NO levels and to decrease the Na+/K+ ATPase activity in HK2 cells. Obtaining Nps-AEA/PCL by electrospraying would represent a promising methodology for a novel AEA pharmaceutical formulation development with optimal physicochemical properties, physical stability and biological activity on HK2 cells.
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Affiliation(s)
- Virna M Martín Giménez
- Instituto de Investigaciones en Ciencias Químicas, Facultad de Ciencias Químicas y Tecnológicas, Universidad Católica de Cuyo, Av. Ignacio de la Roza 1516 (o), 5400, San Juan, Argentina
| | - Marcos G Russo
- Departamento de Química, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Almirante Brown 1455, D5700HGC, San Luis, Argentina
| | - Griselda E Narda
- Departamento de Química, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Almirante Brown 1455, D5700HGC, San Luis, Argentina
| | - Lucía B Fuentes
- Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 917, D5700HOJ, San Luis, Argentina
| | - Luciana Mazzei
- Laboratorio de Farmacología Experimental Básica y Traslacional. Área de Farmacología, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Av. Libertador 80 - Parque General San Martín, Centro Universitario, M5500 Mendoza, Argentina
| | - Carlos Gamarra-Luques
- Instituto de Medicina y Biología Experimental de Cuyo, Consejo Nacional de Investigación Científica y Tecnológica (IMBECU-CONICET), Av. Ruiz Leal s/n - Parque Gral. San Martín, M5500 Mendoza, Argentina
| | - Diego E Kassuha
- Instituto de Investigaciones en Ciencias Químicas, Facultad de Ciencias Químicas y Tecnológicas, Universidad Católica de Cuyo, Av. Ignacio de la Roza 1516 (o), 5400, San Juan, Argentina
| | - Walter Manucha
- Laboratorio de Farmacología Experimental Básica y Traslacional. Área de Farmacología, Departamento de Patología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Av. Libertador 80 - Parque General San Martín, Centro Universitario, M5500 Mendoza, Argentina.
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Mugica I, Fito C, Domat M, Dohányosová P, Gutierrez-Cañas C, López-Vidal S. Novel techniques for detection and characterization of nanomaterials based on aerosol science supporting environmental applications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 609:348-359. [PMID: 28753510 DOI: 10.1016/j.scitotenv.2017.06.184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/20/2017] [Accepted: 06/22/2017] [Indexed: 06/07/2023]
Abstract
The number of people exposed to nanoparticles is growing accordingly to the production and development of new nanomaterials. Moreover, this increase is expected to continue in the future. However, there is a lack of standardized sampling and metric methods to measure the level of exposure to nanoparticles, and the information related to possible adverse health effects is scarce. Aerosol technology has been detecting and characterizing nanoparticles for decades and some of their developments can be of use in nanotechnology characterization. We present here two current developments based on used principles in aerosol science, which can widen its application to the characterization of nanomaterials. On the one hand, a sample preparation technique for nanoparticle analysis by electron microscopy based on electrospray atomization technology. Several samples prepared in this way have been analysed and compared to more traditional sample preparation strategies like the "drop on grid" method. It was found that the particles deposited by electrospray generally show a much more homogeneous spatial distribution on the substrate and the number of single particles increases substantially. On the other hand, it is presented an electrical mobility classification system, DMA, with enormous possibilities for the quick and economic size characterization of suspensions of nanoparticles, thanks to its injection system by electrospray and to its high resolution in the lower range of the nanoscale. The first assessment of the abovementioned devices highlights its potential applications in exposure assessment and nanotechnological contexts.
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Affiliation(s)
- Iñaki Mugica
- RAMEM S.A, C/ Verano 9, 28850 Torrejón de Ardoz, Madrid, Spain.
| | - Carlos Fito
- ITENE, C/ Albert Einstein, 1, 46980 Paterna, Valencia, Spain
| | - Maidá Domat
- ITENE, C/ Albert Einstein, 1, 46980 Paterna, Valencia, Spain
| | | | - Cristina Gutierrez-Cañas
- Department of Chemistry and Environmental Engineering, University of the Basque Country UPV/EHU, Alda. Urquijo s/n, 48013 Bilbao, Spain
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