The role played by organic components in the process of biosilicification, resulting in well-defined three-dimensional silica structures in algae, has not been completely clarified. Especially in the case of diatoms several organic components have been meanwhile identified, including silaffins, silacidins, and polyamines. In this study we perform classical and quantum molecular dynamics simulations addressing two major issues related to polyamines: 1) the possible protonation states and protonation sites in short polyamines, and 2) the interaction of differently protonated polyamines with silica surfaces in order to identify the possible molecular conformations in dependence on the degree of protonation. Our results are in good quantitative agreement with results based on NMR experiments.
The role played by organic components in the process of biosilicification, resulting in well-defined three-dimensional silica structures in algae, has not been completely clarified. Especially in the case of diatoms several organic components have been meanwhile identified, including silaffins, silacidins, and polyamines. In this study we perform classical and quantum molecular dynamics simulations addressing two major issues related to polyamines: 1) the possible protonation states and protonation sites in short polyamines, and 2) the interaction of differently protonated polyamines with silica surfaces in order to identify the possible molecular conformations in dependence on the degree of protonation. Our results are in good quantitative agreement with results based on NMR experiments.