A Cytoprotective and Degradable Metal–Polyphenol Nanoshell for Single‐Cell Encapsulation

Abstract Single‐cell encapsulation promises the cytoprotection of the encased cells against lethal stressors, reminiscent of the sporulation process in nature. However, the development of a cytocompatible method for chemically mimicking the germination process (i.e., shell degradation on‐demand) has been elusive, despite the shell degradation being pivotal for the practical use of functional cells as well as for single cell‐based biology. We report that an artificial shell, composed of tannic acid (TA) and Fe III , on individual Saccharomyces cerevisiae controllably degrades on‐demand, while protecting the yeast from multiple external aggressors, including UV‐C irradiation, lytic enzymes, and silver nanoparticles. Cell division is suppressed by the TA–Fe III shell, but restored fully upon shell degradation. The formation of a TA–Fe III shell would provide a versatile tool for achieving the chemical version of “sporulation and germination”.