Variable aggregation rates in colloidal gold: Kernel homogeneity dependence on aggregant concentration

Olivier, Bernard J.; Sorensen, C. M.

doi:10.1103/physreva.41.2093

Cited by 43 publications

(26 citation statements)

References 24 publications

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“…5). Exponential increase in weight-averaged aggregate mass can be associated with either reactionlimited cluster-cluster aggregation 42,43 or secondary nucleation mechanisms. 28,44,45 Secondary nucleation mechanisms are often observed for fibril-forming proteins capable of generating new fibril ends by branching or breakage mechanisms, and reactionlimited cluster-cluster aggregation is a coagulation process where the rate of coalescence of two clusters is not dependent upon cluster size.…”

Section: Coagulation Governs Aggregate Growthmentioning

confidence: 99%

Aggregation of a multidomain protein: A coagulation mechanism governs aggregation of a model IgG1 antibody under weak thermal stress

et al. 2010

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Using an IgG1 antibody as a model system, we have studied the mechanisms by which multidomain proteins aggregate at physiological pH when incubated at temperatures just below their lowest thermal transition. In this temperature interval, only minor changes to the protein conformation are observed. Light scattering consistently showed two coupled phases: an initial fast phase followed by several hours of exponential growth of the scattered intensity. This is the exact opposite of the lagtime behavior typically observed in protein fibrillation. Dynamic light scattering showed the rapid formation of an aggregate species with a hydrodynamic radius of about 25 nm, which then increased in size throughout the experiment. Theoretical analysis of our light scattering data showed that the aggregate number density goes through a maximum in time providing compelling evidence for a coagulation mechanism in which aggregates fuse together. Both the analysis as well as size-exclusion chromatography of incubated samples showed the actual increase in aggregate mass to be linear and reach saturation long before all molecules had been converted to aggregates. The CH2 domain is the only domain partly unfolded in the temperature interval studied, suggesting a pivotal role of this least stable domain in the aggregation process. Our results show that for multidomain proteins at temperatures below their thermal denaturation, transient unfolding of a single domain can prime the molecule for aggregation, and that the formation of large aggregates is driven by coagulation.

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Section: Coagulation Governs Aggregate Growthmentioning

confidence: 99%

Aggregation of a multidomain protein: A coagulation mechanism governs aggregation of a model IgG1 antibody under weak thermal stress

et al. 2010

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“…Scaling arguments have been used [18]to predict that in the intermediate regimes the growth of the average mass is given by M=t' "~' , 0&A, &1. (4) THE EXPERIMENTAL SETUP Since the fractal morphology can be best evaluated from the asymptotic behavior of the scattered intensity, we have used a low-angle scattering setup covering almost two decades in scattering wave vectors, from q =4X 10 to q =3 X 10 Values of A, at variance with those characteristic of DLCA and RLCA have been reported in a recent paper [22] but very little work has been done to investigate in a systematic way the intermediate regimes.…”

Section: Theorymentioning

confidence: 99%

Coagulation kinetics and aggregate morphology in the intermediate regimes between diffusion-limited and reaction-limited cluster aggregation

et al. 1992

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We investigate the kinetics and fractal morphology of aggregating polystyrene latex in an intermediate region between diffusion-limited cluster aggregation (DLCA) and reaction-limited cluster aggregation (RLCA). The measurements are made by means of a low-angle elastic-light-scattering setup covering two decades in scattering wave vectors. For each aggregation run, the salt concentration c is changed and the samples are prepared under isopycnic conditions, to avoid differential sedimentation. The average cluster mass is found to grow according to a power law with an exponent z varying in a continuous fashion in the range of salt concentration used. At high c (DLCA), we find for the fractal morphology df =1.65. For lower concentrations, df is at first larger than 2 and therefore close to the typical RLCA fractal dimension, but then it gradually reverts to lower values not far from those typical of DLCA. This behavior is also exhibited at the lowest values of c explored, although the decay to DLCA is much slower. An interpretation of the results is presented on the basis of the available theories and simulation work on the cluster morphology in the intermediate regimes.

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“…1. Between these regimes exists either a crossover (Lin et al 1990) or a continuous evolution of k from 0 to 1 (Olivier and Sorensen 1990). None of the work on colloidal fractal aggregation measured the rate coef cients of the aggregation.…”

Section: Introductionmentioning

confidence: 97%

Aggregation Kernel Homogeneity for Fractal Aggregate Aerosols in the Slip Regime

Wang

Sorensen

2001

Aerosol Science and Technology

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A theoretical description of the aggregation kernel homogeneity for fractal aggregates in the slip regime is developed. Experimental values of the kernel homogeneity were determined with dynamic light scattering measurements on titania and silica aerosols at pressures of 1/10 to one atmosphere. These experiments yielded aggregates with a fractal dimension of ca. 1.75 and aggregate radii to cover a range of Knudsen numbers of 0.04 -3.8. Measurement of the fractal aggregate mobility radius as a function of time during aggregation gave the homogeneity. Agreement of theory and experiment is in general successful.

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Variable aggregation rates in colloidal gold: Kernel homogeneity dependence on aggregant concentration

Cited by 43 publications

References 24 publications

Aggregation of a multidomain protein: A coagulation mechanism governs aggregation of a model IgG1 antibody under weak thermal stress

Aggregation of a multidomain protein: A coagulation mechanism governs aggregation of a model IgG1 antibody under weak thermal stress

Coagulation kinetics and aggregate morphology in the intermediate regimes between diffusion-limited and reaction-limited cluster aggregation

Aggregation Kernel Homogeneity for Fractal Aggregate Aerosols in the Slip Regime

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