Characterization of Small Molecule Controlled Release From Silk Films

Abstract Release data for several dyes from untreated, water‐annealed, and methanol‐treated silk films are collected and modeled. Through modeling, Fickian diffusion is identified as the major release mechanism. Estimated diffusivities are compared with dye properties to characterize parameter–property relationships. FTIR–ATR spectra of the silk films confirm an increase in the crystalline beta‐sheet content within the silk films for methanol‐treated and water‐annealed films. An aqueous binding study is completed and shows weak binding of three dyes to the silk films. The Langmuir equation is fit to each of the binding curves and compared. The rate of diffusion from silk films is highly impacted by the molecular structure, water solubility, and molecular charge of the releasing solute and the matrix crystallinity.