Electron tomography for revealing biomaterial nanostructure and its implications

The 3 Dimensional macromolecular structure of wood cells plays a major role in the properties of single cells and ultimately entire tissues. Similarly, all products made from wood and processes used for treating or deconstructing wood cells/fibres are affected by its ultimate nanostructure. Despite its importance, the nanostructure of the secondary cell walls of wood fibres remains unresolved. We have developed techniques for studying the macromolecular structure of wood fibres and have produced idealized 3 D-polymeric models of cellulose–lignin-hemicellulose matrices. Our approach involves processing wood samples by advanced Cryo-techniques (rapid freezing/freeze substitution) followed by high resolution Transmission Electron Microscopy (TEM) electron tomography (ET), the latter providing stacks of images (tomograms) for 3D reconstruction imaging. In this project, we will refine our HR-TEM-ET approach and examine a wider range of physiologically different wood cell types as well as industrial processed fibres (chemical/mechanical pulp fibres) where changes in fibre nanostructure are important for energy savings and deconstruction of cell walls for biofuels. In particular, we will develop a complete Cryo-approach from rapid freezing to freeze-sectioning and Cryo-TEM of fibres. We will further use tomogram reconstructions for simulations to determine if macro-properties from wood can be predicted from quantifying the nano-macromolecular structures of secondary cell wall layers