Artificial Spores: Cytocompatible Coating of Living Cells with Plant-Derived Pyrogallol

Cell nanoencapsulation, generating cell-in-shell structures ("artificial spores"), provides a chemical toolbox for controlling the cellular behaviors and functional characteristics of individual cells. Among the shell materials studied so far, naturally occurring polyphenolic compounds, including polydopamine and tannic acid, have intensively been employed in cell-surface engineering, because their material-independent coating property eliminates an extra priming step for inducing subsequent shell formation. Albeit successful in generating cell-in-shell structures, the coating of polyphenolic compounds generally requires alkaline conditions and/or high salt conditions, which are not compatible with certain cell types. In this work, we demonstrate that the nanocoating of individual cells with a plant-derived phenolic compound, pyrogallol (1,2,3-trihydroxybenzene), occurs at mildly alkaline pH of 7.8 in an isotonic buffer. Three different cell types (anucleate, microbial, and mammalian cells) are coated with pyrogallol without noticeable decrease in cell viability. The protocol developed in this work could be applied to other polyphenolic compounds, and, considering the many polyphenols identified as a coating material, provides an advanced chemical tool in cell-surface engineering.