Polymers, Colloids & Interfaces, Contributed Talk (15min)

Bacteria-Induced Mineralization of 3D Printed Hydrogel Structures

M. Hirsch1, S. Ait Said1, A. Clarà Saracho2, E. Amstad1*
1Soft Materials Laboratory, Institute of Materials, École polytechnique fédérale de Lausanne, 1015 Lausanne, 2Soil Mechanics Laboratory, School of Architecture, Civil and Environmental Engineering, École polytechnique fédérale de Lausanne, 1015 Lausanne

Despite recent advances in the field of hydrogel inks for 3D printing applications, the ability to precisely control their local composition remains unexplored. The introduction of particle-based inks enabled the possibility to engineer mechanical and chemical gradients within the printed constructs with unparalleled precision. However, the capability of homogeneously integrating inorganic components, such as biominerals, in the hydrogel ink, while maintaining good mechanical integrity, still remains a major challenge. Inspired by nature, we mimic the biomineralization process often observed in crustaceans and mussels, where inorganic crystals are precipitated in a gelatinous matrix. Here, we introduce a 3D printing approach to fabricate biomineralized hydrogel structures by encapsulating ureolytic bacteria in a granular bioink. The resulting printed structure can be easily stabilized with no harm to the bacteria, and the mineralization can be initiated simply by urea exposure. The final biomineral-gel composite is able to retain the initial shape and support its own weight. This new technique promises to further extend the field of 3D hydrogel printing enabling the fabrication of new hybrid materials for the production of next generation biomineral composites.