Measuring the size and density of nanoparticles by centrifugal sedimentation and flotation

Minelli, Caterina; Sikora, Aneta; Garcia-Diez, Raul; Sparnacci, Katia; Gollwitzer, Christian; Krumrey, Michael; Shard, Alexander G.

doi:10.1039/c8ay00237a

Cited by 52 publications

(42 citation statements)

References 29 publications

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“…DCS98,99 determines the size distribution and density of nanoparticles by its sedimentation time in fluids during differential centrifugation. DCS works for particles with sizes ranging98d between 10 nm and 50 µm and has the ability to distinguish polydisperse particle distributions with size difference of less97a than 3% even in strongly agglomerated samples when nanoparticles are exposed to biological media 98c.…”

Section: Characterization Of Reticular Nanoparticlesmentioning

confidence: 99%

“…The friction coefficient f depends on the temperature dependent viscosity η of the solvent and the hydrodynamic radius R H of a hypothetical spherical particle that has the same translational diffusion as the particle under investigation. Technically, DCS is realize using a rotating transparent disc,98d which is filled by a fluid density gradient, often made of water sucrose 98a. This liquid gradient ring is created by a series of injections of mixtures with decreasing density.…”

Section: Characterization Of Reticular Nanoparticlesmentioning

confidence: 99%

See 1 more Smart Citation

The Chemistry of Reticular Framework Nanoparticles: MOF, ZIF, and COF Materials

Ploetz

Engelke

Lächelt

et al. 2020

Adv Funct Materials

212

145

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Nanoparticles have become a vital part of a vast number of established processes and products; they are used as catalysts, in cosmetics, and even by the pharmaceutical industry. Despite this, however, the reliable and reproducible production of functional nanoparticles for specific applications remains a great challenge. In this respect, reticular chemistry provides methods for connecting molecular building blocks to nanoparticles whose chemical composition, structure, porosity, and functionality can be controlled and tuned with atomic precision. Thus, reticular chemistry allows for the translation of the green chemistry principle of atom economy to functional nanomaterials, giving rise to the multifunctional efficiency concept. This principle encourages the design of highly active nanomaterials by maximizing the number of integrated functional units while minimizing the number of inactive components. State-ofthe-art research on reticular nanoparticles-metal-organic frameworks, zeolitic imidazolate frameworks, and covalent organic frameworks-is critically assessed and the beneficial features and particular challenges that set reticular chemistry apart from other nanoparticle material classes are highlighted. Reviewing the power of reticular chemistry, it is suggested that the unique possibility to efficiently and straightforwardly synthesize multifunctional nanoparticles should guide the synthesis of customized nanoparticles in the future.

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Section: Characterization Of Reticular Nanoparticlesmentioning

confidence: 99%

Section: Characterization Of Reticular Nanoparticlesmentioning

confidence: 99%

The Chemistry of Reticular Framework Nanoparticles: MOF, ZIF, and COF Materials

Ploetz

Engelke

Lächelt

et al. 2020

Adv Funct Materials

212

145

View full text Add to dashboard Cite

show abstract

“…Over the last decade, significant efforts have been made to develop and validate methods for accurate sizing of monodisperse and near-spherical nanoparticles. These methods include popular techniques such as electron microscopy [ 10 , 11 , 12 ], dynamic light scattering [ 13 , 14 , 15 ], disc-type centrifugal liquid sedimentation [ 13 , 14 , 15 , 16 , 17 ], and particle tracking analysis [ 18 , 19 , 20 , 21 ]. Method validation is important to demonstrate that a method is working as expected and therefore it is a key step during the process of standardization.…”

Section: Introductionmentioning

confidence: 99%

Validation of a Homogeneous Incremental Centrifugal Liquid Sedimentation Method for Size Analysis of Silica (Nano)particles

et al. 2020

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Silica nanoparticles display many unique physicochemical properties that make them desirable for use in a wide variety of consumer products and composite materials. Accurately measuring the size of these nanoparticles is important for achieving the desired nanoscale functionality of the final product and for regulatory compliances. This study covers the validation of a centrifugal liquid sedimentation method for accurate measurement of the Stokes diameter of silica particles with a near-spherical shape and dimensions in the nanometer and sub-nanometer scale range. The validated method provided unbiased results in the range of 50 nm to 200 nm, with a lower limit of detection of ≤20 nm. The relative standard uncertainties for precision, quantified in terms of repeatability and day-to-day variation, ranged from 0.2% to 1.0% and from <0.1% to 0.5%, respectively. The standard uncertainty for trueness was assessed at 4.6%. Within its working range, the method was found robust with respect to the type of cuvette, light factor, operator, and for defining the meniscus of the sample suspension. Finally, a relative expanded measurement uncertainty of 10% confirmed the satisfactory performance of the method.

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“…In the first description of MSC exosomes, the presence of a lipid membrane was demonstrated through several lines of evidence. First, the proteins in the preparation had a flotation density of 1.10-1.18 g ml 1 that lies between the liposome density of 1.04-1.05 g ml 1 (6) and the estimated protein density of 1.35-1.42 g ml 1 (7). Second, the tetraspanin proteins CD9 and CD81 were enriched in the exosome preparation and were shown to be partially resistant to trypsin digestion.…”

mentioning

confidence: 99%

Membrane lipids define small extracellular vesicle subtypes secreted by mesenchymal stromal cells

Lai

Lim

2019

Journal of Lipid Research

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Therapeutic efficacy of the mesenchymal stromal cell (MSC), a multipotent progenitor cell, is attributed to small (50 to 200 nm) extracellular vesicles (EVs). The presence of a lipid membrane differentiates exosomes and EVs from other macromolecules. Analysis of this lipid membrane revealed three distinct small MSC EV subtypes each with a differential affinity for cholera toxin B chain (CTB), annexin V (AV), and shiga toxin B chain (ST) that binds GM1 ganglioside, phosphatidylserine, and globotriaosylceramide, respectively. Similar EV subtypes are also found in biologic fluids and are independent sources of disease biomarkers. Here, we compared and contrasted these three EV subtypes. All subtypes carry β-actin, but only CTB-binding EVs (CTB-EVs) are true exosomes, enriched with exosome proteins and derived from endosomes. No unique protein has been identified yet in AV-binding EVs (AV-EVs); ST-binding EVs (ST-EVs) carry RNA and a high level of extra domain A (EDA)-containing fibronectin. Based on the CTB, AV, and ST subcellular binding sites, the origins of CTB-, AV- and ST-EV biogenesis are the plasma membrane, cytoplasm, and nucleus, respectively. The differentiation of EV subtypes through membrane lipids underlies the importance of membrane lipids in defining EVs and implies an influence on EV biology and functions.

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Measuring the size and density of nanoparticles by centrifugal sedimentation and flotation

Abstract: Analytical centrifugation in sedimentation and flotation modes is used to measure both the size and density of polystyrene nanoparticles.

Cited by 52 publications

References 29 publications

The Chemistry of Reticular Framework Nanoparticles: MOF, ZIF, and COF Materials

The Chemistry of Reticular Framework Nanoparticles: MOF, ZIF, and COF Materials

Validation of a Homogeneous Incremental Centrifugal Liquid Sedimentation Method for Size Analysis of Silica (Nano)particles

Membrane lipids define small extracellular vesicle subtypes secreted by mesenchymal stromal cells

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