Engineering encapsulated living bacteria for advanced healthcare management

Bacterial therapies are emerging as promising alternatives to conventional treatments, particularly in the areas of intestinal therapy, oncology, and wound management. However, gastric acid, bile salts, immune cells, and reactive oxygen species in the human body hinder the colonization and growth of foreign probiotics, thereby compromising the efficacy of bacteriotherapy. Recent advancements in engineering encapsulated live bacteria strategies utilizing biopolymers to construct protective shells on the bacterial surface to significantly address the aforesaid challenges have gained unprecedented attention. The scrumptious integration of multiple probiotic species, bioencapsulation biomaterials, and on-demand encapsulation technologies offers tremendous advantages over conventional living bacterial counterparts, such as precise targeting, rapid immune activation, and synergistic therapeutic effects. This review presents the essential natures and response mechanism selectivity for encapsulation biomaterials from the design perspective of engineered bacterial therapeutics, including pH-responsive, enzyme-responsive, and reactive oxygen species (ROS)-responsive materials. Engineering bacterium requires a uniquely tailored design strategy within the polymer-targeted delivery platform. Meanwhile, the review provides an account of its recent developments and advancements in the biomedical fields, with emphasis on tissue repair, anti-inflammatory, antibacterial, anti-tumor, and other therapeutic applications. Finally, challenges and emerging trends in its clinical translation are expounded. By highlighting the potential of bacteria to revolutionise the therapeutic landscape, this review offers valuable insights into the design of innovative disease treatment paradigms and alternatives to conventional drug therapy, and facilitates the clinical applications of engineering encapsulated living bacteria.