Structure formation aggregation kinetics

In vitro, fibril formation by several proteins displays an initial lag phase, followed by a rapid increase in aggregation (reviewed in Rochet and Lansbury, 2000). Introduction of fibrillar seeds eliminates the lag phase. These cooperative aggregation kinetics suggest that fibril formation begins with the formation of a nucleus and proceeds by fibril extension. The structure of the nucleus must therefore act as a template for the protein s conformation in the fibril. As the structural requirements for templating are unclear, it is difficult to assess the consistency of the model classes with this feature of fibril formation. We have described one possible templating mechanism for the cross-/ spine of GNNQQNY (Nelson et al., 2005). 

Chapters 4 and 5 [34, 35], A number of computer simulations and statistical models have been proposed to explain growth, polymerization and aggregation processes that lead to the formation of fractal structures that closely resemble those found in nature. Attempts have been made to relate the fractal dimensions of aggregates to their formation mechanisms and aggregation kinetics. 

Aggregation starts with the formation of doublets which is a rather easily modelled process. In the subsequent aggregation, a multitude of irregular particles are formed and a conventional kinetic treatment then becomes more or less impossible. The structure of the particle aggregates is dependent on the interaction potentials. Some information can be obtained by computer simulations. We will start our consideration of the aggregation kinetics by a discussion of the Smoluchowski theory and its ramifications on more recent work. 

Figure 22 Structure formation in thin films from liquids (A) temporal evolution of concentrations, interactions, and viscosity due to drying and (B) interplay between drying and aggregation kinetics. Reprinted from Gunther and Peukert (2(X)3). Copyright 2003, with permission from Elsevier.

The situation changes if we take into account the possible influence of supramolecular structures formation kinetics on rheological properties within the aggregative model of oligomer liquids structure. We must assume ... 

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