Nanoencapsulation in polymeric materials: Weaving magical coats for microorganisms

As natural organisms, microorganisms have many inherent limitations and shortcomings making them unable to meet many requirements of commercial application. In general, formulation processes, such as encapsulation, were necessary to improve the performance of microorganisms. In recent years, nanoencapsulation, an encapsulation technology with cell-in-shell structures as its distinguish feature, has been rapidly developed and applied to encapsulate microorganisms with shells that endows their cells with exogenous properties, such as cascade organic-catalysis, UV blocking, immunogenic shielding, and tolerance against other harmful factors. Herein, we reviewed the progress of nanoencapsulation for microorganisms from many perspectives, including its definition, materials used, strategies, effectiveness, application, and future. As a new technology, nanoencapsulation differs from and exceeds other encapsulation technologies in many features. A variety of materials have been used in the nanoencapsulation of beneficial microorganisms, including biopolymers, synthetic polymers, metal–organic complexes, biominerals, metal-organic frameworks (MOFs), and nanomaterials. Several strategies have been developed and employed in recent years to encapsulate living microbial cells, including LbL self-assembly, bioinspired mineralization, metal–ligand interaction based self-assembly, and bio-interface polymerization. Nanoencapsulation technology provided beneficial microorganisms with advantages like providing them coats with magics, namely protection and preservation, germination and growth suppression, functionalization and post-functionalization, and controlled release by degradation.