Diffusion in Colloidal and Polymeric Systems

Nägele, Gerhard; Dhont, Jan K. G.; Meier, G.

doi:10.1007/3-540-30970-5_16

Cited by 6 publications

(9 citation statements)

References 99 publications

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“…The form of eq suggests that G D ( t ) in that case can approximately be expressed as a correlation function for a particle of the same size but fluorescently labeled only in the center and illuminated by an effectively larger beam of the intensity profile defined in the reciprocal space by The effective beam profile is also assumed to be Gaussian to preserve the simple analytical form of the time correlation function (eq ). This can be achieved, for example, by fitting | B ( qa )| with a function ( A e –(1/2) kq 2 a 2 ), which allows the effective beam waist size in the x–y plane to be expressed as , In refs and a value of k = 0.22 was reported; however, it was obtained for fitted value of A ( A ≠ 1) and for fitting range reaching the first secondary maximum of | B ( qa )|. Combining eq with eq leads to where τ 0 is the correlation time of a particle of the same size but fluorescently labeled only in the center and τ c is the correlation time fitted to the measured correlation function using eq .…”

Section: Resultsmentioning

confidence: 99%

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Size of Submicrometer Particles Measured by FCS: Correction of the Confocal Volume

Deptuła¹,

Buitenhuis

Jarzębski³

et al. 2015

Langmuir

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When fluorescence correlation spectroscopy (FCS) in combination with a confocal microscope is used to determine the hydrodynamic radius a of particles comparable to or larger than the linear size σ of the confocal volume of the microscope, a correction must be used that depends on the a(2)/σ(2) ratio and the distribution of the dye within the particle. Here we present the experimental validation of the theoretically predicted approximate correction necessary for appropriate measurements of the size of uniformly fluorescently labeled spheres of radius comparable to the size of the confocal volume. We also test the approximate correction formula for different ranges of the a/σ ratio and propose a simple procedure to obtain the correct nanoparticle size from such a measurement.

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Section: Resultsmentioning

confidence: 99%

“…The size of the effective confocal volume for a uniformly labeled spherical NP has been previously calculated, , and the approximate simple correction formula was proposed.…”

Section: Introductionmentioning

confidence: 99%

Size of Submicrometer Particles Measured by FCS: Correction of the Confocal Volume

Deptuła¹,

Buitenhuis

Jarzębski³

et al. 2015

Langmuir

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“…In the case of particles comparable in size to the size of the confocal volume, diffusion times measured by FCS are not proportional to the particle size. A proper correction was proposed in a former study [39]. The proposed model was successfully validated for the polymeric and silica particles, whose diameters were larger than 500 nm [36].…”

Section: H1mentioning

confidence: 95%

Fluorescent Submicron-Sized Poly(heptafluoro-n-butyl methacrylate) Particles with Long-Term Stability

et al. 2020

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Fluorescent submicron particles of fluorinated methacrylate (HFMBA) with long-term stability have been synthesized and characterized with regard to their potential applications. Rhodamine B (RBITC) isothiocyanate was used as the fluorescent component. The core–shell structure of the particles effectively protected the dye against bleaching. HFBMA nanoparticle (NP) stability was confirmed after seven years of storage. Only slight differences were found in the polydispersity index (pdi) from 0.002 to 0.010. Particle size measurements were carried out using dynamic light scattering (DLS), nanoparticle tracking (NTA), and fluorescence correlation spectroscopy (FCS). The hydrodynamic diameter evaluated by different methods were in good agreement, respectively: 184–550 nm, 218–579 nm, and 236–508 nm. Particle and core morphology was estimated by using scanning and transmission electron microscopy (SEM and TEM). The ability to recognize particles in 3D as a reference sample in biological media has been confirmed by epifluorescence optical microscopy, confocal laser scanning microscopy, and super-resolution confocal microscopy (STED).

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Section: Methodsmentioning

confidence: 99%

“…In the case where the size of the fluorescent particle becomes comparable to or larger than the focal spot dimensions, the size and shape of the particle, the dye distribution within the particle, and other modes of motion (except translation) have to be considered. For spherical particles with a spherically symmetric dye distribution the rotational modes do not contribute, and the normalized FCS CF can be numerically calculated as where is the Fourier transform (FT) of the Gaussian beam intensity profile and B ( q ) is the FT of the function χ( r ) describing the dye distribution within the colloidal particle: For a uniform dye distribution, | B ( q )| 2 is equal to the static form factor, well-known in all scattering techniques, however, with the restriction that it refers only to the labeled part of the particle. The fluorescent form factor of a sphere of radius a with homogeneous fluorescent core radius a c has the form while that of a thin spherical shell Hence, for a body-labeled particle eq and for a surface labeled particle eq should be used.…”

Section: Methodsmentioning

confidence: 99%

Structure and Dimensions of Core–Shell Nanoparticles Comparable to the Confocal Volume Studied by Means of Fluorescence Correlation Spectroscopy

Gapiński¹,

Jarzębski

Buitenhuis

et al. 2016

Langmuir

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In some applications the dye distribution within fluorescently labeled nanoparticles and its stability over long periods of time are important issues. In this article we study numerically and experimentally the applicability of fluorescence correlation spectroscopy (FCS) to resolve such questions. When the size of fluorescently labeled particles is comparable to or larger than the confocal volume, the effective confocal volume seen in FCS experiments is increasing. Such an effect has already been studied for uniformly labeled spherical particles. In this work we analyze the form of the FCS correlation functions (CFs) for core-labeled and shell-labeled core-shell particles. For shell-labeled particles an additional fast decay was found both in simulations and in experiments on custom-made surface-labeled particles. Universal scaling of FCS correlation times based on the squared ratio of the labeled part radius of gyration to the Gaussian radius of the beam profile was found. Recipes based on the analysis of simulated CFs, proposed for interpretation of experimental results, were successfully applied to the FCS results on suspensions of large core-labeled and surface-labeled particles.

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Diffusion in Colloidal and Polymeric Systems

Cited by 6 publications

References 99 publications

Size of Submicrometer Particles Measured by FCS: Correction of the Confocal Volume

Size of Submicrometer Particles Measured by FCS: Correction of the Confocal Volume

Fluorescent Submicron-Sized Poly(heptafluoro-n-butyl methacrylate) Particles with Long-Term Stability

Structure and Dimensions of Core–Shell Nanoparticles Comparable to the Confocal Volume Studied by Means of Fluorescence Correlation Spectroscopy

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