Silk-based products, formulations, and methods of use

A method of preparing processed silk fibroin, comprising

• providing silk yarn harvested from a silk producer, the silk yarn comprising silk fibers containing silk fibroin and sericin,
• degumming the silk yarn in greater than 0.3 to 0.5 M sodium carbonate at a temperature of about 80 to about 90° C., and for a time of 60 to 480 minutes, to provide degummed silk fibers having a sericin concentration of 0-0.5 wt %,
• dissolving the degummed silk fibers using 5M to 13M lithium bromide for 4 hours to overnight at 60° C. to 85° C. to provide dissolved silk fibers, or dissolving the degummed silk fibers using a mixture of calcium chloride, ethanol, and water in a molar ratio of 1:2:8,
• diluting the dissolved silk fibers in water to form a solution with a concentration of 5 to 20% w/v silk fibers and optionally filtering the solution through a polypropylene prefilter to remove particulates and provide a clarified silk fiber solution,
• performing tangential flow filtration (TFF) on the diluted or clarified silk fiber solution using a regenerated cellulose filter, and
• concentrating and recovering processed silk fibroin from the TFF,
• wherein the processed silk fibroin has an average molecular weight of 5-50 kDa as determined by high pressure liquid chromatography using a standard comprising Thyroglobulin, IgG, bovine serum albumin (BSA), Myoglobin, and Uracil.