Aligned Electrospun Starch-Pullulan-Protein Nanofibers
Open Access
- Author:
- Mukka, Shravya
- Graduate Program:
- Food Science
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 07, 2022
- Committee Members:
- Robert Roberts, Program Head/Chair
Greg Ziegler, Thesis Advisor/Co-Advisor
Helene Hopfer, Committee Member
Josephine Wee, Committee Member - Keywords:
- starch
WPI
GMP
electrospinning
biodegradable
biocompatible
bioactive
cultivated meat
edible
OSA starch
pullulan
nanofibers
aligned nanofibers
scaffold
GRAS - Abstract:
- Nanofiber scaffolds fabricated using GRAS (generally recognized as safe) materials like polysaccharides and proteins are ideal for cell cultured meat applications due to their biodegradability, biocompatibility, bioactivity, and edibility. In this work, I aimed to electrospin two types of proteins – whey protein isolate (WPI) and glycomacropeptide (GMP) – as part of a multi-component mixture along with two polysaccharides – octenyl succinic anhydride modified starch (OSA starch) and pullulan. Protein acts as a functionalizer to improve cell migration, adhesion, and proliferation on the electrospun nanofiber mats. OSA starch was used for its superior water solubility and dispersibility properties. Pullulan was added to enhance spinnability and to aid in the formation of smooth fibers. A mixture design was created to spin the solutions in different component concentrations while keeping the overall polymer concentration constant at 30% (w/w). Electrospinning was performed under fixed parameters (constant voltage, flow rate, and needle tip to collector distance) to focus on the effect of changing component concentrations on fiber morphology. 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 fibers with beading. Generally, GMP-containing nanofibers exhibited less beading than WPI-containing nanofibers. Solutions were characterized for conductivity, surface tension and rheological properties. Solutions containing GMP had higher viscosities than solutions containing WPI. Fibers were characterized for diameter and morphology via scanning electron microscopy and images analyzed using ImageJ. Fibers within the average diameter range of 459 and 565 nm were obtained from GMP-containing solutions, while WPI-containing solutions yielded fibers within the average diameter range of 461 and 526 nm. Additionally, the effect of humidity on fiber morphology was also examined. It was observed that discontinuous beaded fibers were obtained from WPI-containing solutions at relative humidity levels greater than ~ 10% and greater than ~ 20% from GMP-containing solutions. Aligned fiber mats were produced using a rotating drum collector at different speeds (3600, 4200, 4900 and 5600 rpm) to aid in directional growth and proliferation of cultivated cells. The results from this work provide an encouraging sustainable process to fabricate functional nanofiber scaffolding that can aid in promoting satellite cell adhesion, alignment, proliferation, and differentiation to myoblasts for cell-cultivated meat applications.