Cell Surface Engineering with Edible Protein Nanoshells

Abstract

Natural protein (silk fibroin) nanoshells are assembled on the surface of Saccharomyces cerevisiae yeast cells without compromising their viability. The nanoshells facilitate initial protection of the cells and allow them to function in encapsulated state for some time period, afterwards being completely biodegraded and consumed by the cells. In contrast to a traditional methanol treatment, the gentle ionic treatment suggested here stabilizes the shell silk fibroin structure but does not compromise the viability of the cells, as indicated by the fast response of the encapsulated cells, with an immediate activation by the inducer molecules. Extremely high viability rates (up to 97%) and preserved activity of encapsulated cells are facilitated by cytocompatibility of the natural proteins and the formation of highly porous shells in contrast to traditional polyelectrolyte-based materials. Moreover, in a high contrast to traditional synthetic shells, the silk proteins are biodegradable and can be consumed by cells at a later stage of growth, thus releasing the cells from their temporary protective capsules. These on-demand encapsulated cells can be considered a valuable platform for biocompatible and biodegradable cell encapsulation, controlled cell protection in a synthetic environment, transfer to a device environment, and cell implantation followed by biodegradation and consumption of protective protein shells.

Biofabrication of 3D constructs: fabrication technologies and spider silk proteins as bioinks

“…Silk-based biomaterials have been used for medical sutures and breast implant coatings [70][71][72], biosensing applications [73], and enzyme immobilization [74][75][76]. Recently, a silk-gelatin blend was used as a bioink [20,57].…”

Strategic Advances in Formation of Cell‐in‐Shell Structures: From Syntheses to Applications

“…The most intensively employed method in single‐cell nanocoating is the LbL deposition of various polymers and nanomaterials onto cell surfaces ( Figure a) . In addition to the classical, electrostatics‐based LbL deposition that might be cytotoxic because of positively charged polyelectrolytes, new strategies have been developed for more cytocompatible cell nanocoating, such as salting‐out‐ and hydrogen bonding‐based approaches. [4a,b,13] For example, Tsukruk and co‐workers formed tough, pH‐responsive LbL shells on individual yeast cells, by cross‐linking hydrogen‐bonded layers composed of poly( N ‐vinylpyrrolidone) (PVPON) and amine‐bearing poly(methacrylic acid) (PMAA‐ co ‐NH 2 ), to control cell function and metabolism without noticeable decrease in cell viability (Figure b).…”

“…[4a,b,13] For example, Tsukruk and co‐workers formed tough, pH‐responsive LbL shells on individual yeast cells, by cross‐linking hydrogen‐bonded layers composed of poly( N ‐vinylpyrrolidone) (PVPON) and amine‐bearing poly(methacrylic acid) (PMAA‐ co ‐NH 2 ), to control cell function and metabolism without noticeable decrease in cell viability (Figure b). [13a] The material scope for cell‐surface engineering also has been widened, including silk fibroin (SF), halloysite nanotubes (Figure c), and small peptides …”

Single‐Cell Nanometric Coating Towards Whole‐Cell‐Based Biodevices and Biosensors

“…One key property of silk protein is that its solubility can be adjusted by salting‐out in a proper ionic mixture complemented with shear‐thinning effect, with the transition from water‐soluble Silk I to non‐soluble β‐sheet‐rich Silk II, based on which, the silk‐based coating can be smartly put on or taken off. Hence, in this work, the yeast cells were coated with ultrathin silk shells, maintaining a high viability (∼97%), the ability of budding and replication, as well as the metabolic activity. Since the silk shell undergoes relatively rapid intracellular degradation, there is only a short‐term protection of the cells.…”