Engineered living biomaterials

Biomaterials have evolved from inert materials that lack interaction with the body to biologically active, instructive materials that host and provide signals to surrounding cells and tissues. Engineered living materials contain living cells (responsive function) and polymeric matrices (scaffolding function) and, thus, can be designed as active and response biomaterials. In this Review, we discuss engineered living materials that incorporate microorganisms as the living, bioactive component. Microorganisms can provide complex responses to environmental stimuli, and they can be genetically engineered to allow user control over responses and integration of numerous inputs. The engineered microorganisms can either generate their own matrix, such as in biofilms, or they can be incorporated in matrices using various technologies, such as coating, 3D printing, spinning and microencapsulation. We highlight biomedical applications of such engineered living materials, including biosensing, wound healing, stem-cell-based tissue engineering and drug delivery, and provide an outlook to the challenges and future applications of engineered living materials. Engineered living materials are composed of a matrix that encapsulates living cells, which endow the biomaterial with controllable responses and dynamic functions. This Review discusses the fabrication and biomedical applications of engineered living materials that contain microorganisms as the living, active component.