The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adom.202202643.

In this work, we demonstrate the preparation of oriented bacterial cellulose from Komagataeibacter sucrofermentans by rheotactic growth in a simple and adaptable setup. The resulting materials were assessed by their yields, geometric densities, and by X-ray diffraction, scanning electron and optical microscopy, and mechanical testing. They exhibited large differences in toughness, resulting from differences in fracture strain or highly anisotropic strengths. Their growth characteristics, structural and mechanical anisotropies and crystalline phase characteristics are discussed and compared to statically grown references and to instances from the literature. Here, we consider the length scales of structural anisotropy in native bacterial cellulose pellicles, and the origin of mechanical anisotropy. Further, we identify a tentative limit on achievable structural alignment in bacterial cellulose, as well as a correlation between crystallinity and disorder in the crystalline phase of bacterial cellulose.

Structuring cellulosic materials is an important step towards realizing emerging technologies, such as so-called engineered living materials, and improving on established ones, such as tissue engineering. In this work, we present a route for the preparation of cellulose monoliths exhibiting a three-dimensional pattern on the macroscopic scale, together with structural anisotropy in the cellulose fiber level. This was achieved by rheotactic growth, i.e. under flowing medium, of bacterial cellulose over a 3D-printed dissolvable template. The surrounding setup was realized using commercially available components. Here, we report on and discuss structural properties of cellulose monoliths obtained by this process, such as shrinkages during processing, the strut densities of 50 mg cm−3, preferred orientations of cellulose within the struts, and the pore size distributions, which were determined from nanoscale-precision silica replica.

No abstract