Material-based engineering of bacteria for cancer diagnosis and therapy

Abstract Various categories of biomaterials have been utilized for drug delivery, genetic modification, photodynamic and photothermal therapies due to their distinct physicochemical properties, including photothermal convertibility, stimuli-responsiveness, and inherent capability to generate photodynamical radicals. However, successful treatments of cancer are largely hindered by the limited accessibility of nanomaterials into hypoxic or metastatic tumor tissues. Among the various tumor-targeting strategies, bacterial fabrication exhibits particular advantages such as specific hypoxia tropism, high motility, and rapid self-replication. Biomineralization, i.e. bacterial modification, involves the fabrication of bacteria by nanomaterials for precise cancer imaging as well as targeted drug delivery, overcoming the physiological barriers and improving the therapeutic efficiency. Fabrication of bacteria strains can be conducted by various methods, including direct adsorption, electrostatic interaction, covalent ligation, and surface precipitation. In this review, a brief introduction to commonly-utilized biomaterials and bacteria species is provided. A systemic overview of recent advances of bacteria fabrication strategies and techniques are then discussed, followed by future prospective of bacteria-facilitated cancer therapy and diagnostics.