Effects of Guar Gum and Sodium Benzoate on Their Properties and Hydrophilicity of Silk Fibroin Hydrogels

Silk fibroin (SF)-based hydrogels were prepared by simple evaporation method. The outcomes of SF-based hydrogels were assessed for consideration in terms of practical and convenient use. Guar gum (GG) and sodium benzoate (SB) are blending reagents to the SF solution, and then poured in the petri dish to form the hydrogels. After leaving the mixture solution for three days, all SF-based hydrogels were peeled off and characterized. The SF blended guar gum (SF-GG) and SF-GG blended sodium benzoate (SF-GG-SB) could be constructed, but in different textures and transparency. The SB affected the solid texture and resulted in higher water contact angle (WCA) value of the prepared SF hydrogel more than on SF-GG. The results from Fourier transform infrared spectroscopy (FTIR) indicated all the main functional groups of substances that were contained in the blending hydrogels. Moreover, some interactions between the functional groups were also detected. Thermogravimetric analyzer (TGA) was used to determine the hydrogel decomposition as a function of temperature. The DTG thermograms revealed that the interaction forces between blending substances and SF as well as the structure of them are the reason for the thermal stability of the SF-based hydrogels. SF-GG-SB hydrogels have higher tensile strength than the SF-GG hydrogels. In conclusion, appearance, texture, hydrophilicity, thermal stability and tensile strength of the SF-based hydrogels were affected by the types and concentrations of blending substances. This is promising that the SF-based hydrogel properties could be designed and adjusted to have desirable texture for fitting target applications.