Biofabrication of multifunctional nanocellulosic 3D structures: a facile and customizable route

Biomass-based nanomaterials such as bacterial cellulose (BC) are one of the most promising building blocks for the development of sustainable materials with the potential to outperform their conventional, synthetic, counterparts. The formation of BC occurs at the air-water interface, which has been exploited to engineer materials with finely controlled microtopographical features or simple three-dimensionalmorphologies for awide range of applications. However, a high degree of control over the 3D morphology of BC films across several length scales (micro tomacro) has not yet been achieved. Herein, we describe a simple yet customizable process to finely engineer the morphology of BC in all (x, y, z) directions, enabling new advanced functionalities, by using hydrophobic particles and superhydrophobized surfaces. This results in hollow, seamless, cellulose-based objects of given shapes and with sizes from ca. 200 lm to several centimeters. We demonstrate some of the unique properties of the process and the resulting objects via post-fabrication merging (biowelding), by in situ encapsulation of active cargo and by multi-compartmentalization for near limitless combinations, thus extending current and new applications for example in advanced carbon materials or regenerative medicine.