Engineering living therapeutics and diagnostics: A new frontier in human health

Traditional therapeutics aim to diagnose, treat, and cure diseases through various synthetic and natural approaches. The emerging field of engineered living therapeutics (ELTs) genetically functionalizes living cells to alter the paradigm of designed solutions. In this review, we focus on ELTs derived from microbial cell scaffolds. We propose three synergistic modalities for the rational design of ELTs: first, use of regulatory operations to regulate genetic expression; second, integration of alternative biosensing inputs for directed application; third, choice of microbial chassis to deliver solutions. We highlight the challenges and future opportunities within each group and conclude by providing a prospective outlook for ELTs.