Edible electrospun materials for scalable cultivated beef production

Cultivated meats are a direct response to an ever-increasing global demand for meat, that will alleviate the negative impacts of animal farming on the environment and food security. Despite recent advances, however, challenges regarding scalability and costs remain, impeding the availability and affordability of these novel foods. Consequently, this study aims to design novel edible and biocompatible scaffolds for the expansion of bovine mesenchymal stem cells, using silk fibroin from degummed Bombyx mori cocoons. The scaffolds were created from 12% (w/w) silk fibroin in formic acid via two different methods of electrospinning, a needle-based laboratory set-up and a needleless configuration with the ability to produce non-woven fabrics at industrial scale. The supports were further treated with methanol or ethanol, which induced β-sheet crystallisation and preserved their fibrous nature in an aqueous environment for at least 2 weeks, with <10% total weight loss. Although the highly porous nanofibrous morphology was maintained in all cases (98-166 nm fibre diameters), the alcohol treatments increased the stiffness, strength and brittleness of the materials by 6-fold, 5-fold and 3-fold, respectively. When different seeding densities (1500, 3000 and 5000 cells/cm2) of bovine mesenchymal stem cells were investigated, there were no signs of cytotoxicity, and the best growth was achieved at the lowest cell density, yielding a 9-fold expansion, with a 0.018 h-1 specific growth rate and 44 h doubling time over 7 days. These findings provide novel insights into electrospun materials and may support future developments in cultivated meats.