Cell Encapsulation and Functionality in Engineered Living Microfibers by Uniaxial Electrospinning

The ability to print living materials in architected geometries enables superior control over cell functionality that will surely enhance the future of biofuel, pharmaceutical, and biocatalyst production. Bulk living materials – or biocompatible hydrogels with encapsulated microbes – may face the challenge of slow mass transfer that limits their production capacity. Cell functionality can be greatly improved when living materials are fabricated in precise geometries such as lattices & scaffolds, which also favor biocatalysis. Here, we present a novel uniaxial electrospinning approach to developing microfibrous poly(ethylene glycol) (PEG) constructs for single cell-level encapsulation and bioprocess intensification. This approach allows PEG microfibers to be generated from an aqueous solution of poly(ethylene glycol) diacrylate (PEGDA), which cannot be conventionally electrospun on its own. By adding a sufficient amount of salt, surfactant, and high molecular weight poly(ethylene oxide) (PEO) to the solution; we can obtain micron sized PEG/PEO fibers loaded with viable yeast cells and having an average fiber diameter of 0.8 μm. Upon photo-curing with a water-soluble initiator, the PEO can be washed away to produce swellable PEG microfibers with encapsulated microbes. Since yeast can be genetically modified to produce a variety of other valuable products, like biofuels or pharmaceuticals, this material could find use as a biocatalyst in industrial processes or as a platform for designing bioinspired materials with other lifelike functions.