Alzheimer's disease is the most common form of senile dementia. This neurodegenerative disorder is characterized by an amyloid deposition in senile plaques, composed primarily of fibrils of an aggregated peptide, amyloid beta (A beta). The modeling of a senile plaque formation on a model neuronal membrane under the physiological condition is an attractive issue. In this study, we used anionic liposomes to model the senile plaque formation by A beta. The growth behavior of amyloid All fibrils was directly observed, revealing that the induction of the spherulitic A beta aggregates could result from the growth of seeds in the presence of anionic liposomes. The seeds of A beta fibrils strongly interacted with negatively charged liposome and the subsequent association of the seeds were induced to form the seed cluster with many growth ends, which is advantageous for the formation of spherulitic A beta aggregates. Therefore, anionic liposomes mediated not only fibril growth but also the aggregation process. These results imply that anionic liposome membranes would affect the aggregate form of All fibrils. The modeling of senile plaque reported here is considered to have great potential for study on the amyloidosis. (c) 2012 Elsevier Inc. All rights reserved.