Effect of methylcellulose on the formation and drug release behavior of silk fibroin hydrogel.

In this study, methylcellulose (MC) was used to control the gelation time of silk fibroin (SF) aqueous solution. The gelation time was measured using a Vibro Viscometer at 50 °C. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and a texture meter were used to investigate the effect of MC on the hydrogelation of SF solution. SF/MC hydrogels could be formed by the addition of MC, although their gelation time was increased with MC content. To examine the conformational change of SF/MC hydrogels, time-resolved FT-IR spectra were obtained at constant temperature using a custom-made IR chamber. From FT-IR spectra focused on the amide I peak position, the transition of SF molecules in SF/MC solution from a random coil to a β-sheet structure was inhibited in the presence of MC molecules. In addition, the drug release of SF/MC hydrogels loaded with 5-aminosalicylic acid was studied in 2-dimensional (2-D) and 3-dimensional (3-D) conditions in vitro. The drug release behavior of SF or SF/MC hydrogels was measured using UV-Vis spectroscopy. The release rate of 5-aminosalicylic acid in SF/MC hydrogel was lower than that of SF hydrogel, which may be closely associated with the hydrophilic interaction between MC and 5-aminosalicylic acid. This approach to controlling the sol-gel transition and the drug release of SF hydrogels by the addition of MC will be useful in the design and tailoring of novel materials for biomedical applications.