Microbially controlled colloidal shaping of advanced ceramics

Advanced ceramics find applications in aerospace, energy harvesting and medical technologies. Despite their unique properties, the controlled manufacturing of ceramics with complex geometries is a recurring challenge in the field. Here, a novel manufacturing platform is reported for the colloidal shaping of advanced ceramics using the metabolism of living microorganisms. In this method, bacteria are employed to change the pH of colloidal suspensions in situ , thus enabling casting and time-delayed coagulation of ceramic wet parts in complex-shaped molds. Two distinct bacteria, S. pasteurii and E. coli , are used to investigate the coagulation kinetics of the fabrication process using alumina and zirconia as representative examples of ceramic particles with distinct surface chemistries. The experimental results reveal that the metabolism of bacteria provide an effective mechanism to generate strong ceramic parts with controllable coagulation speed combined with the cost-effective recovery of the microorganisms. These unique features illustrate the potential of engineered living materials for the manufacturing of advanced ceramics.