Engineering Corynebacterium glutamicum as a multifunctional biofactory for living therapeutic materials and controlled ectoine delivery.

Living therapeutic materials (LTMs) are an emerging class of biomaterials that integrate living cells within engineered polymer matrices to provide dynamic and responsive functionalities. In this study, we engineered the robust, nonpathogenic, and GRAS-certified microorganism Corynebacterium glutamicum into a multifunctional biofactory for LTM applications. Using synthetic biology, we designed and constructed C. glutamicum strains capable of sensing, reporting, and producing the extremolyte ectoine. Ectoine is a clinically used compatible solute with cytoprotective and anti-inflammatory properties that is widely applied in dermatological formulations, nasal sprays, and ophthalmic preparations for the treatment of inflammatory and stress-related conditions. The engineered strains were further encapsulated in polymer-based living materials, including membrane-in-gel patches and core-shell hydrogel systems, to create skin-compatible and ocular-applicable therapeutic platforms. We developed genetic biosensors that detect diaminobutyric acid (DABA), a key intermediate in the ectoine biosynthesis pathway, to enable the time-resolved monitoring of cellular function. These biosensors, which are integrated with fluorescence and enzymatic reporter systems, allowed the noninvasive visualization of metabolic activity. Encapsulation strategies were optimized to ensure high metabolic activity, structural stability, and biocontainment, along with the controlled release of ectoine for potential applications in drug delivery and protective therapies. This work highlights the potential of C. glutamicum as a versatile platform for next-generation LTMs, offering precise monitoring and targeted therapeutic capabilities toward multifunctional living materials for precision medicine and environmental biosensing applications.