Strategic advances in the single‐cell nanocoating of mammalian cells have noticeably been made during the last decade, and many potential applications have been demonstrated. Various cell‐coating strategies have been proposed via adaptation of reported methods in the surface sciences and/or materials identification that ensure the sustainability of labile mammalian cells during chemical manipulation. Here an overview of the methodological development and potential applications to the healthcare sector in the nanocoating of mammalian cells made during the last decade is provided. The materials used for the nanocoating are categorized into polymers, hydrogels, polyphenolic compounds, nanoparticles, and minerals, and the corresponding strategies are described under the given set of materials. It also suggests, as a future direction, the creation of the cytospace system that is hierarchically composed of the physically separated but mutually interacting cellular hybrids.

Although metal−phenolic species have emerged as one of the versatile material-independent-coating materials, providing attractive tools for interface engineering, mechanistic understanding of their film formation and growth still remains largely unexplored. Especially, the anions have been overlooked despite their high concentration in the coating solution. Considering that the anions are critical in the reactivity of metal−organic complex and the formation and/or property of functional materials, we investigated the anionic effects on the characteristics of film formation, such as film thickness and properties, in the Fe 3+ −tannic acid coating. We found that the film characteristics were strongly dictated by the counteranions (e.g., SO 4 2− , Cl − , and Br − ) of the Fe 3+ ion. Specifically, the film thickness and properties (i.e., mechanical modulus, permeability, and stability) followed the reversed anionic Hofmeister series (Br − > Cl − > SO 4 2− ). Mechanistic studies suggested that more chaotropic anions, such as Br − , might induce a more widely extended structure of the Fe 3+ −TA complexes in the coating solution, leading to thicker, harder, but more porous films. The reversed anionic Hofmeister effect was further confirmed by the additive effects of various sodium salts (NaF, NaCl, NaBr, and NaClO 4 ).

Manipulation and control of cell chemotaxis remain an underexplored territory despite vast potential in various fields, such as cytotherapeutics, sensors, and even cell robots. Herein is achieved the chemical control over chemotactic movement and direction of Jurkat T cells, as a representative model, by the construction of cell‐in‐catalytic‐coat structures in single‐cell nanoencapsulation. Armed with the catalytic power of glucose oxidase (GOx) in the artificial coat, the nanobiohybrid cytostructures, denoted as Jurkat[Lipo_GOx], exhibit controllable, redirected chemotactic movement in response to d‐glucose gradients, in the opposite direction to the positive‐chemotaxis direction of naïve, uncoated Jurkat cells in the same gradients. The chemically endowed, reaction‐based fugetaxis of Jurkat[Lipo_GOx] operates orthogonally and complementarily to the endogenous, binding/recognition‐based chemotaxis that remains intact after the formation of a GOx coat. For instance, the chemotactic velocity of Jurkat[Lipo_GOx] can be adjusted by varying the combination of d‐glucose and natural chemokines (CXCL12 and CCL19) in the gradient. This work offers an innovative chemical tool for bioaugmenting living cells at the single‐cell level through the use of catalytic cell‐in‐coat structures.