PROJECT ABSTRACT Dissecting the non-growing-but-active state of a hybrid bacteria-material microdevice Recent work has been interested in engineering commensal bacteria to address various biomedical challenges, such as specific drug delivery, gene-editing using CRISPR-Cas, and continuous synthesis of drugs at disease sites. In contrast to non-living devices, bacteria can address these unmet needs because they already live in the human body and at disease sites, move actively towards stimuli, detect and respond to stimuli, and synthesize drugs continuously. However, a significant challenge is to prevent the uncontrolled proliferation of bacteria, while keeping their active functions. To address the challenge, the community must have a foolproof safety measure that prevents the replication of therapeutic bacteria in any condition. This measure will ensure that the bacteria cannot replicate in patients and the large ecosystem. Without replication, mutation is also rare, and mutants cannot spread. Furthermore, a non-replicating entity can be dosed more precisely than an auto-replicating entity. Thus far, however, attempts to stop bacterial replication also compromise the therapeutic activity of bacteria. To address this critical bottleneck, my lab has created bacteria that cannot grow but keep high metabolism by integrating synthetic materials with bacteria. The non-growing- but-active bacteria continue to synthesize proteins, move, and respond to chemical stimuli. My research will further investigate the underlying mechanisms that govern the non-growing-but-active state of the bacteria. The new understanding will then be used to boost and enable specific features of the non-growing-but-active bacteria relevant for future biomedical applications. I will leverage my prior work about synthetic gene expression, bacterial information processing, and CRISPR-dCas9 molecular tools. The work will reveal a new material-protein paradigm for inhibiting growth but preserving the activity of living cells. Furthermore, the work will enable a superior, safe, and active hybrid bacteria-material microdevice for broad biomedical applications.