Cytoprotective Encapsulation of Individual Jurkat T Cells within Durable TiO2 Shells for T-Cell Therapy.

Lymphocytes, such as T cells and natural killer (NK) cells, have therapeutic promise in adoptive cell transfer (ACT) therapy, where the cells are activated and expanded in vitro and then infused into a patient. However, the in vitro preservation of labile lymphocytes during transfer, manipulation, and storage has been one of the bottlenecks in the development and commercialization of therapeutic lymphocytes. Herein, we suggest a cell-in-shell (or artificial spore) strategy to enhance the cell viability in the practical settings, while maintaining biological activities for therapeutic efficacy. A durable titanium oxide (TiO2 ) shell is formed on individual Jurkat T cells, and the CD3 and other antigens on cell surfaces remain accessible to the antibodies. Interleukin-2 (IL-2) secretion is also not hampered by the shell formation. This work suggests a chemical toolbox for effectively preserving lymphocytes in vitro and developing the lymphocyte-based cancer immunotherapy.

Modulation of Heterotypic and Homotypic Cell-Cell Interactions via Zwitterionic Lipid Masks.

Since the pioneering work by Whitesides, innumerable platforms that aim to spatio-selectively seed cells and control the degree of cell-cell interactions in vitro have been developed. These methods, however, have generally been technically and methodologically complex, or demanded stringent materials and conditions. In this work, we introduce zwitterionic lipids as patternable, cell-repellant masks for selectively seeding cells. The lipid masks are easily removed with a routine washing step under physiological conditions (37 °C, pH 7.4), and are used to create patterned cocultures, as well as to conduct cell migration studies. We demonstrate, via patterned cocultures of NIH 3T3 fibroblasts and HeLa cells, that HeLa cells proliferate far more aggressively than NIH 3T3 cells, regardless of initial population sizes. We also show that fibronectin-coated substrates induce cell movement akin to collective migration in NIH 3T3 fibroblasts, while the cells cultured on unmodified substrates migrate independently. Our lipid mask platform offers a rapid and highly biocompatible means of selectively seeding cells, and acts as a versatile tool for the study of cell-cell interactions.

Organic/inorganic double-layered shells for multiple cytoprotection of individual living cells.

The cytoprotection of individual living cells under in vitro and daily-life conditions is a prerequisite for various cell-based applications including cell therapy, cell-based sensors, regenerative medicine, and even the food industry. In this work, we use a cytocompatible two-step process to encapsulate Saccharomyces cerevisiae in a highly uniform nanometric (<100 nm) shell composed of organic poly(norepinephrine) and inorganic silica layers. The resulting cell-in-shell structure acquires multiple resistance against lytic enzyme, desiccation, and UV-C irradiation. In addition to the UV-C filtering effect of the double-layered shell, the biochemical responses of the encapsulated yeast are suggested to contribute to the observed UV-C tolerance. This work offers a chemical tool for cytoprotecting individual living cells under multiple stresses and also for studying biochemical behavior at the cellular level.

Cytoprotective alginate/polydopamine core/shell microcapsules in microbial encapsulation.

Chemical encapsulation of microbes in threedimensional polymeric microcapsules promises various applications, such as cell therapy and biosensors, and provides a basic platform for studying microbial communications. However, the cytoprotection of microbes in the microcapsules against external aggressors has been a major challenge in the field of microbial microencapsulation, because ionotropic hydrogels widely used for microencapsulation swell uncontrollably, and are physicochemically labile. Herein, we developed a simple polydopamine coating for obtaining cytoprotective capability of the alginate capsule that encapsulated Saccharomyces cerevisiae. The resulting alginate/ polydopamine core/shell capsule was mechanically tough, prevented gel swelling and cell leakage, and increased resistance against enzymatic attack and UV-C irradiation. We believe that this multifunctional core/shell structure will provide a practical tool for manipulating microorganisms inside the microcapsules.

Nanocoating of single cells: from maintenance of cell viability to manipulation of cellular activities.

The chronological progresses in single-cell nanocoating are described. The historical developments in the field are divided into biotemplating, cytocompatible nanocoating, and cells in nano-nutshells, depending on the main research focuses. Each subfield is discussed in conjunction with the others, regarding how and why to manipulate living cells by nanocoating at the single-cell level.

Bioinspired, cytocompatible mineralization of silica-titania composites: thermoprotective nanoshell formation for individual chlorella cells.

Hard-shell case: Using a (RKK)4 D8 peptide allows mineralization to occur under cytocompatible conditions. Thus individual Chlorella cells could be encapsulated within a SiO2 -TiO2 nanoshell with high cell viability (87 %). The encapsulated Chlorella showed an almost threefold increase in their thermo-tolerance after 2 h at 45 °C.

Artificial spores: cytocompatible encapsulation of individual living cells within thin, tough artificial shells.

Cells are encapsulated individually within thin and tough shells in a cytocompatible way, by mimicking the structure of bacterial endospores that survive under hostile conditions. The 3D 'cell-in-shell' structures-coined as 'artificial spores'-enable modulation and control over cellular metabolism, such as control of cell division, resistance to external stresses, and surface-functionalizability, providing a useful platform for applications, including cell-based sensors, cell therapy, regenerative medicine, as well as for fundamental studies on cellular metabolism at the single-cell level and cell-to-cell communications. This Concept focuses on chemical approaches to single-cell encapsulation with artificial shells for creating artificial spores, including cross-linked layer-by-layer assembly, bioinspired mineralization, and mussel-inspired polymerization. The current status and future prospects of this emerging field are also discussed.

Cytocompatible encapsulation of individual Chlorella cells within titanium dioxide shells by a designed catalytic peptide.

The individual encapsulation of living cells has a great impact on the areas of single cell-based sensors and devices as well as fundamental studies in single cell-based biology. In this work, living Chlorella cells were encapsulated individually with abiological, functionalizable TiO(2), by a designed catalytic peptide that was inspired by biosilicification of diatoms in nature. The bioinspired cytocompatible reaction conditions allowed the encapsulated Chlorella cells to maintain their viability and original shapes. After formation of the TiO(2) shells, the shells were postfunctionalized by using catechol chemistry. Our work suggests a bioinspired approach to the interfacing of individual living cells with abiological materials in a controlled manner.

Interfacing living yeast cells with graphene oxide nanosheaths.

The first example of the encapsulation of living yeast cells with multilayers of GO nanosheets via LbL self-assembly is reported. The GO nanosheets with opposite charges are alternatively coated onto the individual yeast cells while preserving the viability of the yeast cells, thus affording a means of interfacing graphene with living yeast cells. This approach is expanded by integrating other organic polymers or inorganic nanoparticles to the cells by hybridizing the entries with GO nanosheets through LbL self-assembly. It is demonstrated that incorporated iron oxide nanoparticles can deliver magnetic properties to the biological systems, allowing the integration of new physical and chemical functions for living cells with a combination of GO nanosheets.