Edible Electrospun Nanofiber Scaffolds

Edible nanofiber scaffolds were fabricated from GRAS (generally recognized as safe) materials for cultivated meat applications. Fibers spun from octenyl succinic anhydride modified starch (OSA starch) containing a minor amount of pullulan to enhance spinnability were functionalized with food-grade protein to potentially improve cell adhesion, differentiation, and maturation. Whey protein isolate (WPI) and glycomacropeptide (GMP) were chosen as functionalizers. A mixture design was created to investigate the influence of component concentrations while keeping the overall polymer concentration constant at 30% (w/w). Electrospinning was performed with fixed parameters (constant voltage, flow rate, and needle tip to collector distance) to focus on the effect of changing component concentrations on fiber morphology. Spinning dopes were characterized for conductivity, surface tension, and rheological properties. Fibers were characterized for diameter distribution and morphology via scanning electron microscopy and image analyses. Smooth, continuous fibers on the nanoscale range were obtained from mixtures that contained less than 4% (w/w) protein, whereas mixtures with greater than 6% (w/w) protein resulted in beaded fibers. GMP-containing nanofibers exhibited less beading than WPI-containing nanofibers. The time scale of fiber beading (Ï„), proportional to the ratio of the viscosity to the surface tension, was used to characterize the spinning process. At constant total polymer concentration, an increase in the fraction protein resulted in a decrease in viscosity with only slight changes in surface tension, therefore, Ï„ decreased and greater beading was observed. Beading increased with relative humidity due to the extended drying time. Fibers containing GMP averaged 459-565 nm in diameter, while those containing WPI averaged 461-526 nm. Aligned fiber mats were produced using a rotating drum collector at different speeds (3600, 4200, 4900 and 5600 rpm) to potentially aid in directional growth of cells for cultivated meat.